diff --git a/core/busy.ts b/core/busy.ts
index 03746fa1..0ee3b863 100644
--- a/core/busy.ts
+++ b/core/busy.ts
@@ -1,7 +1,7 @@
 import { atom, computed } from 'nanostores'
 
-import { onEnvironment } from './environment.js'
-import { hasFeeds } from './feed.js'
+import { onEnvironment } from './environment.ts'
+import { hasFeeds } from './feed.ts'
 
 const $tasks = atom(0)
 
diff --git a/core/category.ts b/core/category.ts
index 20831d5c..b40fb7a4 100644
--- a/core/category.ts
+++ b/core/category.ts
@@ -9,9 +9,9 @@ import {
 } from '@logux/client'
 import { nanoid } from 'nanoid'
 
-import { getClient } from './client.js'
-import type { FeedValue } from './feed.js'
-import { commonMessages as common } from './messages/index.js'
+import { getClient } from './client.ts'
+import type { FeedValue } from './feed.ts'
+import { commonMessages as common } from './messages/index.ts'
 
 export type CategoryValue = {
   id: string
diff --git a/core/client.ts b/core/client.ts
index 1ab50e02..ead3e09b 100644
--- a/core/client.ts
+++ b/core/client.ts
@@ -4,10 +4,10 @@ import { TestPair, TestTime } from '@logux/core'
 import { SUBPROTOCOL } from '@slowreader/api'
 import { atom } from 'nanostores'
 
-import { onEnvironment } from './environment.js'
-import { SlowReaderError } from './error.js'
-import { computeFrom, readonlyExport } from './lib/stores.js'
-import { userId } from './settings.js'
+import { onEnvironment } from './environment.ts'
+import { SlowReaderError } from './error.ts'
+import { computeFrom, readonlyExport } from './lib/stores.ts'
+import { userId } from './settings.ts'
 
 let testTime: TestTime | undefined
 
diff --git a/core/devtools.ts b/core/devtools.ts
index 6f82e6cd..7200f2f7 100644
--- a/core/devtools.ts
+++ b/core/devtools.ts
@@ -1,8 +1,8 @@
-import { busyDuring } from './busy.js'
-import { createDownloadTask } from './download.js'
-import { getFeedLatestPosts, loadFeeds } from './feed.js'
-import { loadFilters, prepareFilters } from './filter.js'
-import { addPost, deletePost, loadPosts, processOriginPost } from './post.js'
+import { busyDuring } from './busy.ts'
+import { createDownloadTask } from './download.ts'
+import { getFeedLatestPosts, loadFeeds } from './feed.ts'
+import { loadFilters, prepareFilters } from './filter.ts'
+import { addPost, deletePost, loadPosts, processOriginPost } from './post.ts'
 
 export async function fillFeedsWithPosts(): Promise<void> {
   await busyDuring(async () => {
diff --git a/core/download.ts b/core/download.ts
index 0dc2246c..39e0b02a 100644
--- a/core/download.ts
+++ b/core/download.ts
@@ -1,5 +1,5 @@
-import { warning } from './devtools.js'
-import { request } from './request.js'
+import { warning } from './devtools.ts'
+import { request } from './request.ts'
 
 export interface TextResponse {
   readonly contentType: string
diff --git a/core/environment.ts b/core/environment.ts
index 0a07923d..9d4c7a09 100644
--- a/core/environment.ts
+++ b/core/environment.ts
@@ -8,8 +8,8 @@ import {
 } from '@nanostores/persistent'
 import { atom, type ReadableAtom, type StoreValue } from 'nanostores'
 
-import { SlowReaderError } from './error.js'
-import type { BaseRoute, BaseRouter, Route, Routes } from './router.js'
+import { SlowReaderError } from './error.ts'
+import type { BaseRoute, BaseRouter, Route, Routes } from './router.ts'
 
 interface LogStoreCreator {
   (): ClientOptions['store']
diff --git a/core/export.ts b/core/export.ts
index 8a01525b..2d96c5f2 100644
--- a/core/export.ts
+++ b/core/export.ts
@@ -6,10 +6,10 @@ import {
   feedsByCategory,
   getCategories,
   getCategoryTitle
-} from './category.js'
-import { type FeedValue, getFeeds } from './feed.js'
-import { readonlyExport } from './lib/stores.js'
-import { getPosts, type PostValue } from './post.js'
+} from './category.ts'
+import { type FeedValue, getFeeds } from './feed.ts'
+import { readonlyExport } from './lib/stores.ts'
+import { getPosts, type PostValue } from './post.ts'
 
 type FeedWithPosts = {
   posts?: PostValue[]
diff --git a/core/fast.ts b/core/fast.ts
index 3c9e12c2..320e91dc 100644
--- a/core/fast.ts
+++ b/core/fast.ts
@@ -6,15 +6,15 @@ import {
   type CategoryValue,
   GENERAL_CATEGORY,
   loadCategories
-} from './category.js'
-import { client } from './client.js'
-import { onEnvironment } from './environment.js'
-import { BROKEN_FEED, type FeedValue, loadFeed, loadFeeds } from './feed.js'
-import { loadFilters } from './filter.js'
-import { listenMany, readonlyExport } from './lib/stores.js'
-import { deletePost, getPost, loadPosts } from './post.js'
-import type { PostValue } from './post.js'
-import { type Route, router } from './router.js'
+} from './category.ts'
+import { client } from './client.ts'
+import { onEnvironment } from './environment.ts'
+import { BROKEN_FEED, type FeedValue, loadFeed, loadFeeds } from './feed.ts'
+import { loadFilters } from './filter.ts'
+import { listenMany, readonlyExport } from './lib/stores.ts'
+import { deletePost, getPost, loadPosts } from './post.ts'
+import type { PostValue } from './post.ts'
+import { type Route, router } from './router.ts'
 
 function notEmpty<Value>(array: Value[]): array is [Value, ...Value[]] {
   return array.length > 0
diff --git a/core/feed.ts b/core/feed.ts
index 8be5e742..934a4285 100644
--- a/core/feed.ts
+++ b/core/feed.ts
@@ -12,12 +12,12 @@ import {
 import { nanoid } from 'nanoid'
 import { atom, onMount } from 'nanostores'
 
-import { client, getClient } from './client.js'
-import { createDownloadTask } from './download.js'
-import { type OptionalId, readonlyExport } from './lib/stores.js'
-import { type LoaderName, loaders } from './loader/index.js'
-import { deletePost, loadPosts, recalcPostsReading } from './post.js'
-import type { PostsPage } from './posts-page.js'
+import { client, getClient } from './client.ts'
+import { createDownloadTask } from './download.ts'
+import { type OptionalId, readonlyExport } from './lib/stores.ts'
+import { type LoaderName, loaders } from './loader/index.ts'
+import { deletePost, loadPosts, recalcPostsReading } from './post.ts'
+import type { PostsPage } from './posts-page.ts'
 
 export type FeedValue = {
   categoryId: string
diff --git a/core/filter.ts b/core/filter.ts
index 71fd0bb4..17aa9dff 100644
--- a/core/filter.ts
+++ b/core/filter.ts
@@ -10,9 +10,9 @@ import {
 } from '@logux/client'
 import { nanoid } from 'nanoid'
 
-import { getClient } from './client.js'
-import type { FeedValue } from './feed.js'
-import { type OriginPost, recalcPostsReading } from './post.js'
+import { getClient } from './client.ts'
+import type { FeedValue } from './feed.ts'
+import { type OriginPost, recalcPostsReading } from './post.ts'
 
 const QUERY_REGEXP = /^(not\s+)?([\w]+)(?:\(([^]+)\))?$/
 
diff --git a/core/i18n.ts b/core/i18n.ts
index a5fb3866..77e6b6c9 100644
--- a/core/i18n.ts
+++ b/core/i18n.ts
@@ -1,7 +1,7 @@
 import { createI18n, type TranslationLoader } from '@nanostores/i18n'
 import { atom } from 'nanostores'
 
-import { onEnvironment } from './environment.js'
+import { onEnvironment } from './environment.ts'
 
 let $locale = atom('en')
 
diff --git a/core/import.ts b/core/import.ts
index 06e8cf68..e1cdf83e 100644
--- a/core/import.ts
+++ b/core/import.ts
@@ -5,11 +5,11 @@ import {
   addCategory,
   type CategoryValue,
   type FeedsByCategory
-} from './category.js'
-import { addFeed, type FeedValue } from './feed.js'
-import { readonlyExport } from './lib/stores.js'
-import { importMessages } from './messages/index.js'
-import { createFeedFromUrl } from './preview.js'
+} from './category.ts'
+import { addFeed, type FeedValue } from './feed.ts'
+import { readonlyExport } from './lib/stores.ts'
+import { importMessages } from './messages/index.ts'
+import { createFeedFromUrl } from './preview.ts'
 
 let $importedFeedsByCategory = atom<FeedsByCategory>([])
 let $importedCategories = atom<string[]>([])
diff --git a/core/index.ts b/core/index.ts
index c30f961d..8bc10672 100644
--- a/core/index.ts
+++ b/core/index.ts
@@ -1,27 +1,27 @@
-export * from './busy.js'
-export * from './category.js'
-export * from './client.js'
-export * from './devtools.js'
-export * from './download.js'
-export * from './environment.js'
-export * from './error.js'
-export * from './export.js'
-export * from './fast.js'
-export * from './feed.js'
-export * from './filter.js'
-export * from './filter.js'
-export * from './html.js'
-export * from './i18n.js'
-export * from './import.js'
-export * from './loader/index.js'
-export * from './messages/index.js'
-export * from './not-found.js'
-export * from './post.js'
-export * from './posts-page.js'
-export * from './preview.js'
-export * from './refresh.js'
-export * from './request.js'
-export * from './router.js'
-export * from './settings.js'
-export * from './slow.js'
-export * from './two-steps.js'
+export * from './busy.ts'
+export * from './category.ts'
+export * from './client.ts'
+export * from './devtools.ts'
+export * from './download.ts'
+export * from './environment.ts'
+export * from './error.ts'
+export * from './export.ts'
+export * from './fast.ts'
+export * from './feed.ts'
+export * from './filter.ts'
+export * from './filter.ts'
+export * from './html.ts'
+export * from './i18n.ts'
+export * from './import.ts'
+export * from './loader/index.ts'
+export * from './messages/index.ts'
+export * from './not-found.ts'
+export * from './post.ts'
+export * from './posts-page.ts'
+export * from './preview.ts'
+export * from './refresh.ts'
+export * from './request.ts'
+export * from './router.ts'
+export * from './settings.ts'
+export * from './slow.ts'
+export * from './two-steps.ts'
diff --git a/core/loader/atom.ts b/core/loader/atom.ts
index 163062ab..aa7b08c5 100644
--- a/core/loader/atom.ts
+++ b/core/loader/atom.ts
@@ -1,14 +1,14 @@
-import type { TextResponse } from '../download.js'
-import type { OriginPost } from '../post.js'
-import { createPostsPage } from '../posts-page.js'
-import type { Loader } from './index.js'
+import type { TextResponse } from '../download.ts'
+import type { OriginPost } from '../post.ts'
+import { createPostsPage } from '../posts-page.ts'
+import type { Loader } from './index.ts'
 import {
   findAnchorHrefs,
   findImageByAttr,
   findLinksByType,
   isHTML,
   toTime
-} from './utils.js'
+} from './utils.ts'
 
 function parsePosts(text: TextResponse): OriginPost[] {
   let document = text.parseXml()
diff --git a/core/loader/index.ts b/core/loader/index.ts
index b80cb0a0..c5679e3a 100644
--- a/core/loader/index.ts
+++ b/core/loader/index.ts
@@ -1,8 +1,8 @@
-import type { DownloadTask, TextResponse } from '../download.js'
-import type { PostsPage } from '../posts-page.js'
-import { atom } from './atom.js'
-import { jsonFeed } from './json-feed.js'
-import { rss } from './rss.js'
+import type { DownloadTask, TextResponse } from '../download.ts'
+import type { PostsPage } from '../posts-page.ts'
+import { atom } from './atom.ts'
+import { jsonFeed } from './json-feed.ts'
+import { rss } from './rss.ts'
 
 export type Loader = {
   getMineLinksFromText(response: TextResponse): string[]
diff --git a/core/loader/json-feed.ts b/core/loader/json-feed.ts
index e956bf56..de4aa36d 100644
--- a/core/loader/json-feed.ts
+++ b/core/loader/json-feed.ts
@@ -1,15 +1,15 @@
-import { warning } from '../devtools.js'
-import type { TextResponse } from '../download.js'
-import type { OriginPost } from '../post.js'
-import { createPostsPage } from '../posts-page.js'
-import type { Loader } from './index.js'
+import { warning } from '../devtools.ts'
+import type { TextResponse } from '../download.ts'
+import type { OriginPost } from '../post.ts'
+import { createPostsPage } from '../posts-page.ts'
+import type { Loader } from './index.ts'
 import {
   findAnchorHrefs,
   findLinksByType,
   isHTML,
   toTime,
   unique
-} from './utils.js'
+} from './utils.ts'
 
 // https://www.jsonfeed.org/version/1.1/
 interface JsonFeed {
diff --git a/core/loader/rss.ts b/core/loader/rss.ts
index 629d71c6..1f2895b6 100644
--- a/core/loader/rss.ts
+++ b/core/loader/rss.ts
@@ -1,7 +1,7 @@
-import type { TextResponse } from '../download.js'
-import type { OriginPost } from '../post.js'
-import { createPostsPage } from '../posts-page.js'
-import type { Loader } from './index.js'
+import type { TextResponse } from '../download.ts'
+import type { OriginPost } from '../post.ts'
+import { createPostsPage } from '../posts-page.ts'
+import type { Loader } from './index.ts'
 import {
   findAnchorHrefs,
   findImageByAttr,
@@ -9,7 +9,7 @@ import {
   isHTML,
   toTime,
   unique
-} from './utils.js'
+} from './utils.ts'
 
 const MEDIA_NS_URI = 'http://search.yahoo.com/mrss/'
 
diff --git a/core/loader/utils.ts b/core/loader/utils.ts
index ce38ce61..7e281597 100644
--- a/core/loader/utils.ts
+++ b/core/loader/utils.ts
@@ -1,4 +1,4 @@
-import type { TextResponse } from '../download.js'
+import type { TextResponse } from '../download.ts'
 
 export function isString(attr: null | string): attr is string {
   return typeof attr === 'string' && attr.length > 0
diff --git a/core/messages/common/en.ts b/core/messages/common/en.ts
index ac7b2ff3..cbc67b4f 100644
--- a/core/messages/common/en.ts
+++ b/core/messages/common/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const commonMessages = i18n('common', {
   brokenCategory: 'Broken category',
diff --git a/core/messages/export/en.ts b/core/messages/export/en.ts
index f2d57233..6c91acc7 100644
--- a/core/messages/export/en.ts
+++ b/core/messages/export/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const exportMessages = i18n('export', {
   allFeeds: 'All feeds',
diff --git a/core/messages/fast/en.ts b/core/messages/fast/en.ts
index 843b6e62..41c073f0 100644
--- a/core/messages/fast/en.ts
+++ b/core/messages/fast/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const fastMessages = i18n('fast', {
   noPosts: 'No posts',
diff --git a/core/messages/import/en.ts b/core/messages/import/en.ts
index e1cdbacb..1264bf5c 100644
--- a/core/messages/import/en.ts
+++ b/core/messages/import/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const importMessages = i18n('import', {
   allFeeds: 'All feeds',
diff --git a/core/messages/index.ts b/core/messages/index.ts
index 0a92eadf..a666722b 100644
--- a/core/messages/index.ts
+++ b/core/messages/index.ts
@@ -1,11 +1,11 @@
-export * from './common/en.js'
-export * from './export/en.js'
-export * from './fast/en.js'
-export * from './import/en.js'
-export * from './navbar/en.js'
-export * from './organize/en.js'
-export * from './preview/en.js'
-export * from './refresh/en.js'
-export * from './settings/en.js'
-export * from './slow/en.js'
-export * from './start/en.js'
+export * from './common/en.ts'
+export * from './export/en.ts'
+export * from './fast/en.ts'
+export * from './import/en.ts'
+export * from './navbar/en.ts'
+export * from './organize/en.ts'
+export * from './preview/en.ts'
+export * from './refresh/en.ts'
+export * from './settings/en.ts'
+export * from './slow/en.ts'
+export * from './start/en.ts'
diff --git a/core/messages/navbar/en.ts b/core/messages/navbar/en.ts
index 66fa98b6..6748ee0a 100644
--- a/core/messages/navbar/en.ts
+++ b/core/messages/navbar/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const navbarMessages = i18n('navbar', {
   about: 'About the App',
diff --git a/core/messages/organize/en.ts b/core/messages/organize/en.ts
index 37f08061..85115111 100644
--- a/core/messages/organize/en.ts
+++ b/core/messages/organize/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const organizeMessages = i18n('organize', {
   addCategory: 'Add category…',
diff --git a/core/messages/preview/en.ts b/core/messages/preview/en.ts
index 508e53ba..f3c3c5f1 100644
--- a/core/messages/preview/en.ts
+++ b/core/messages/preview/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const previewMessages = i18n('preview', {
   add: 'Subscribe to feed',
diff --git a/core/messages/refresh/en.ts b/core/messages/refresh/en.ts
index 39bdb59b..dba7b1ba 100644
--- a/core/messages/refresh/en.ts
+++ b/core/messages/refresh/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const refreshMessages = i18n('refresh', {
   stop: 'Stop'
diff --git a/core/messages/settings/en.ts b/core/messages/settings/en.ts
index bb793a37..71dd24bf 100644
--- a/core/messages/settings/en.ts
+++ b/core/messages/settings/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const settingsMessages = i18n('settings', {
   about: 'About the App',
diff --git a/core/messages/slow/en.ts b/core/messages/slow/en.ts
index b1f3e81f..2c3ae606 100644
--- a/core/messages/slow/en.ts
+++ b/core/messages/slow/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const slowMessages = i18n('slow', {
   noPosts: 'No posts',
diff --git a/core/messages/start/en.ts b/core/messages/start/en.ts
index 1eed2522..2ad97a64 100644
--- a/core/messages/start/en.ts
+++ b/core/messages/start/en.ts
@@ -1,4 +1,4 @@
-import { i18n } from '../../i18n.js'
+import { i18n } from '../../i18n.ts'
 
 export const startMessages = i18n('start', {
   localButton: 'Start local demo',
diff --git a/core/not-found.ts b/core/not-found.ts
index b46680ef..9a6ccb36 100644
--- a/core/not-found.ts
+++ b/core/not-found.ts
@@ -1,8 +1,8 @@
 import { LoguxUndoError } from '@logux/client'
 import { atom } from 'nanostores'
 
-import { onEnvironment } from './environment.js'
-import { router } from './router.js'
+import { onEnvironment } from './environment.ts'
+import { router } from './router.ts'
 
 export const notFound = atom(false)
 
diff --git a/core/package.json b/core/package.json
index e3afe771..0c0d1397 100644
--- a/core/package.json
+++ b/core/package.json
@@ -12,7 +12,7 @@
     "clean:coverage": "rm -rf coverage"
   },
   "exports": {
-    ".": "./index.js",
+    ".": "./index.ts",
     "./package.json": "./package.json"
   },
   "dependencies": {
@@ -30,7 +30,7 @@
     "@logux/actions": "0.4.0",
     "@types/dompurify": "3.0.5",
     "@types/jsdom": "21.1.7",
-    "better-node-test": "0.5.1",
+    "better-node-test": "0.6.0",
     "c8": "10.1.2",
     "jsdom": "24.1.1",
     "nanospy": "1.0.0"
diff --git a/core/post.ts b/core/post.ts
index 1ea57a2e..6d94966f 100644
--- a/core/post.ts
+++ b/core/post.ts
@@ -11,10 +11,10 @@ import {
 } from '@logux/client'
 import { nanoid } from 'nanoid'
 
-import { getClient } from './client.js'
-import { getFeed } from './feed.js'
-import { loadFilters, prepareFilters } from './filter.js'
-import type { OptionalId } from './lib/stores.js'
+import { getClient } from './client.ts'
+import { getFeed } from './feed.ts'
+import { loadFilters, prepareFilters } from './filter.ts'
+import type { OptionalId } from './lib/stores.ts'
 
 export type OriginPost = {
   full?: string
diff --git a/core/posts-page.ts b/core/posts-page.ts
index 8f628c38..957ec1af 100644
--- a/core/posts-page.ts
+++ b/core/posts-page.ts
@@ -1,6 +1,6 @@
 import { map, type ReadableAtom, type StoreValue } from 'nanostores'
 
-import type { OriginPost } from './post.js'
+import type { OriginPost } from './post.ts'
 
 export interface PostsPageValue {
   hasNext: boolean
diff --git a/core/preview.ts b/core/preview.ts
index 528611bd..e54f97d3 100644
--- a/core/preview.ts
+++ b/core/preview.ts
@@ -7,14 +7,14 @@ import {
   createDownloadTask,
   ignoreAbortError,
   type TextResponse
-} from './download.js'
-import { isMobile, onEnvironment } from './environment.js'
-import { addFeed, type FeedValue, getFeeds } from './feed.js'
-import { readonlyExport } from './lib/stores.js'
-import { type LoaderName, loaders } from './loader/index.js'
-import { addPost, processOriginPost } from './post.js'
-import type { PostsPage } from './posts-page.js'
-import { router } from './router.js'
+} from './download.ts'
+import { isMobile, onEnvironment } from './environment.ts'
+import { addFeed, type FeedValue, getFeeds } from './feed.ts'
+import { readonlyExport } from './lib/stores.ts'
+import { type LoaderName, loaders } from './loader/index.ts'
+import { addPost, processOriginPost } from './post.ts'
+import type { PostsPage } from './posts-page.ts'
+import { router } from './router.ts'
 
 const ALWAYS_HTTPS = [/^twitter\.com\//]
 
diff --git a/core/refresh.ts b/core/refresh.ts
index 3f1279b2..1fdaa2e4 100644
--- a/core/refresh.ts
+++ b/core/refresh.ts
@@ -1,17 +1,17 @@
 import { atom, computed, map } from 'nanostores'
 
-import { createDownloadTask, type DownloadTask } from './download.js'
+import { createDownloadTask, type DownloadTask } from './download.ts'
 import {
   changeFeed,
   type FeedValue,
   getFeed,
   getFeedLatestPosts,
   loadFeeds
-} from './feed.js'
-import { type FilterChecker, loadFilters, prepareFilters } from './filter.js'
-import { createQueue, type Queue, retryOnError } from './lib/queue.js'
-import { increaseKey, readonlyExport } from './lib/stores.js'
-import { addPost, type OriginPost, processOriginPost } from './post.js'
+} from './feed.ts'
+import { type FilterChecker, loadFilters, prepareFilters } from './filter.ts'
+import { createQueue, type Queue, retryOnError } from './lib/queue.ts'
+import { increaseKey, readonlyExport } from './lib/stores.ts'
+import { addPost, type OriginPost, processOriginPost } from './post.ts'
 
 let $isRefreshing = atom(false)
 export const isRefreshing = readonlyExport($isRefreshing)
diff --git a/core/router.ts b/core/router.ts
index 50e469d8..a2488bb8 100644
--- a/core/router.ts
+++ b/core/router.ts
@@ -1,11 +1,11 @@
 import { atom, computed, type ReadableAtom } from 'nanostores'
 
-import { getEnvironment, onEnvironment } from './environment.js'
-import { fastCategories } from './fast.js'
-import { hasFeeds } from './feed.js'
-import { computeFrom, readonlyExport } from './lib/stores.js'
-import { userId } from './settings.js'
-import { slowCategories } from './slow.js'
+import { getEnvironment, onEnvironment } from './environment.ts'
+import { fastCategories } from './fast.ts'
+import { hasFeeds } from './feed.ts'
+import { computeFrom, readonlyExport } from './lib/stores.ts'
+import { userId } from './settings.ts'
+import { slowCategories } from './slow.ts'
 
 export interface Routes {
   about: {}
diff --git a/core/settings.ts b/core/settings.ts
index b8909e06..de6e1144 100644
--- a/core/settings.ts
+++ b/core/settings.ts
@@ -1,8 +1,8 @@
 import { persistentAtom } from '@nanostores/persistent'
 import { nanoid } from 'nanoid'
 
-import { getClient } from './client.js'
-import { getEnvironment } from './environment.js'
+import { getClient } from './client.ts'
+import { getEnvironment } from './environment.ts'
 
 export const userId = persistentAtom<string | undefined>('slowreader:userId')
 
diff --git a/core/slow.ts b/core/slow.ts
index 7ea45102..3e6abc48 100644
--- a/core/slow.ts
+++ b/core/slow.ts
@@ -6,13 +6,13 @@ import {
   type CategoryValue,
   GENERAL_CATEGORY,
   loadCategories
-} from './category.js'
-import { client } from './client.js'
-import { onEnvironment } from './environment.js'
-import { BROKEN_FEED, type FeedValue, loadFeed } from './feed.js'
-import { listenMany, readonlyExport } from './lib/stores.js'
-import { getPost, loadPosts, type PostValue } from './post.js'
-import { type Route, router } from './router.js'
+} from './category.ts'
+import { client } from './client.ts'
+import { onEnvironment } from './environment.ts'
+import { BROKEN_FEED, type FeedValue, loadFeed } from './feed.ts'
+import { listenMany, readonlyExport } from './lib/stores.ts'
+import { getPost, loadPosts, type PostValue } from './post.ts'
+import { type Route, router } from './router.ts'
 
 export type SlowCategoriesTree = [CategoryValue, [FeedValue, number][]][]
 
diff --git a/core/test/busy.test.ts b/core/test/busy.test.ts
index 092fbb6c..e2bc1774 100644
--- a/core/test/busy.test.ts
+++ b/core/test/busy.test.ts
@@ -2,8 +2,8 @@ import { equal } from 'node:assert'
 import { afterEach, test } from 'node:test'
 import { setTimeout } from 'node:timers/promises'
 
-import { busy, busyDuring } from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+import { busy, busyDuring } from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 afterEach(async () => {
   await cleanClientTest()
diff --git a/core/test/category.test.ts b/core/test/category.test.ts
index d6640e88..07599c7e 100644
--- a/core/test/category.test.ts
+++ b/core/test/category.test.ts
@@ -14,8 +14,8 @@ import {
   loadFeed,
   loadFeeds,
   testFeed
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/client.test.ts b/core/test/client.test.ts
index 906896e1..75619e4e 100644
--- a/core/test/client.test.ts
+++ b/core/test/client.test.ts
@@ -3,8 +3,8 @@ import { cleanStores, keepMount } from 'nanostores'
 import { equal, match, throws } from 'node:assert'
 import { afterEach, test } from 'node:test'
 
-import { client, getClient, userId } from '../index.js'
-import { enableClientTest } from './utils.js'
+import { client, getClient, userId } from '../index.ts'
+import { enableClientTest } from './utils.ts'
 
 enableClientTest()
 
diff --git a/core/test/download.test.ts b/core/test/download.test.ts
index 01c64aba..8d6ee469 100644
--- a/core/test/download.test.ts
+++ b/core/test/download.test.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { equal, rejects, throws } from 'node:assert'
 import { afterEach, beforeEach, test } from 'node:test'
@@ -12,7 +12,7 @@ import {
   ignoreAbortError,
   mockRequest,
   setRequestMethod
-} from '../index.js'
+} from '../index.ts'
 
 beforeEach(() => {
   mockRequest()
diff --git a/core/test/environment.test.ts b/core/test/environment.test.ts
index 45ed9216..247b7f55 100644
--- a/core/test/environment.test.ts
+++ b/core/test/environment.test.ts
@@ -7,7 +7,7 @@ import {
   getTestEnvironment,
   onEnvironment,
   setupEnvironment
-} from '../index.js'
+} from '../index.ts'
 
 test('throws on current environment if it is not set', () => {
   throws(() => {
diff --git a/core/test/environment.ts b/core/test/environment.ts
index f5ba65e1..a3d5594c 100644
--- a/core/test/environment.ts
+++ b/core/test/environment.ts
@@ -1,3 +1,3 @@
-import { getTestEnvironment, setupEnvironment } from '../index.js'
+import { getTestEnvironment, setupEnvironment } from '../index.ts'
 
 setupEnvironment(getTestEnvironment())
diff --git a/core/test/error.test.ts b/core/test/error.test.ts
index ed6752e4..b7c994ff 100644
--- a/core/test/error.test.ts
+++ b/core/test/error.test.ts
@@ -1,7 +1,7 @@
 import { equal, match } from 'node:assert'
 import { test } from 'node:test'
 
-import { SlowReaderError } from '../index.js'
+import { SlowReaderError } from '../index.ts'
 
 test('formats error', () => {
   let error = new SlowReaderError('Test')
diff --git a/core/test/export.test.ts b/core/test/export.test.ts
index ce9f83fa..86398218 100644
--- a/core/test/export.test.ts
+++ b/core/test/export.test.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { cleanStores } from 'nanostores'
 import { deepStrictEqual, equal, ok } from 'node:assert'
@@ -24,8 +24,8 @@ import {
   submiting,
   toggleExportingCategory,
   toggleExportingFeed
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 async function loadFile(name: string): Promise<string> {
   let path = join(import.meta.dirname, 'fixtures', name)
diff --git a/core/test/fast.test.ts b/core/test/fast.test.ts
index 018fb5df..738c50c2 100644
--- a/core/test/fast.test.ts
+++ b/core/test/fast.test.ts
@@ -26,8 +26,8 @@ import {
   setFastPostsPerPage,
   testFeed,
   testPost
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/feed.test.ts b/core/test/feed.test.ts
index 8bc4007b..60a9a636 100644
--- a/core/test/feed.test.ts
+++ b/core/test/feed.test.ts
@@ -24,8 +24,8 @@ import {
   loadFeeds,
   testFeed,
   testPost
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/filter.test.ts b/core/test/filter.test.ts
index 6b3f938f..76642ff2 100644
--- a/core/test/filter.test.ts
+++ b/core/test/filter.test.ts
@@ -19,8 +19,8 @@ import {
   prepareFilters,
   sortFilters,
   testFeed
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/html.test.ts b/core/test/html.test.ts
index 8c4f3014..08250564 100644
--- a/core/test/html.test.ts
+++ b/core/test/html.test.ts
@@ -1,9 +1,9 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { equal } from 'node:assert'
 import { test } from 'node:test'
 
-import { parseLink, parseRichTranslation, sanitizeDOM } from '../index.js'
+import { parseLink, parseRichTranslation, sanitizeDOM } from '../index.ts'
 
 test('sanitizes HTML', () => {
   equal(
diff --git a/core/test/i18n.test.ts b/core/test/i18n.test.ts
index 1ad6bdad..f5e8242f 100644
--- a/core/test/i18n.test.ts
+++ b/core/test/i18n.test.ts
@@ -1,11 +1,11 @@
-import './environment.js'
+import './environment.ts'
 
 import { atom } from 'nanostores'
 import { deepStrictEqual, equal } from 'node:assert'
 import { test } from 'node:test'
 
-import { i18n, settingsMessages } from '../index.js'
-import { enableClientTest } from './utils.js'
+import { i18n, settingsMessages } from '../index.ts'
+import { enableClientTest } from './utils.ts'
 
 test('has i18n', async () => {
   equal(typeof i18n, 'function')
diff --git a/core/test/import.test.ts b/core/test/import.test.ts
index f3b141fd..31a2136d 100644
--- a/core/test/import.test.ts
+++ b/core/test/import.test.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { cleanStores } from 'nanostores'
 import { deepStrictEqual, equal, ok } from 'node:assert'
@@ -26,8 +26,8 @@ import {
   submiting,
   toggleImportedCategory,
   toggleImportedFeed
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 async function importFile(name: string): Promise<string> {
   let path = join(import.meta.dirname, 'fixtures', name)
diff --git a/core/test/lib/queue.test.ts b/core/test/lib/queue.test.ts
index 83ce3495..4771a42d 100644
--- a/core/test/lib/queue.test.ts
+++ b/core/test/lib/queue.test.ts
@@ -2,7 +2,7 @@ import { equal, fail, rejects } from 'node:assert'
 import { test } from 'node:test'
 import { setTimeout } from 'node:timers/promises'
 
-import { createQueue, retryOnError } from '../../lib/queue.js'
+import { createQueue, retryOnError } from '../../lib/queue.ts'
 
 test('increase keys', async () => {
   let events = ''
diff --git a/core/test/lib/store.test.ts b/core/test/lib/store.test.ts
index 85c4f15c..7c1a9870 100644
--- a/core/test/lib/store.test.ts
+++ b/core/test/lib/store.test.ts
@@ -7,7 +7,7 @@ import {
   forceSet,
   increaseKey,
   listenMany
-} from '../../lib/stores.js'
+} from '../../lib/stores.ts'
 
 test('force set', () => {
   let $a: ReadableAtom<number> = atom<number>(1)
diff --git a/core/test/loader/atom.test.ts b/core/test/loader/atom.test.ts
index 8d802822..9537b66e 100644
--- a/core/test/loader/atom.test.ts
+++ b/core/test/loader/atom.test.ts
@@ -1,4 +1,4 @@
-import '../dom-parser.js'
+import '../dom-parser.ts'
 
 import { spyOn } from 'nanospy'
 import { deepStrictEqual, equal } from 'node:assert'
@@ -10,7 +10,7 @@ import {
   createTextResponse,
   loaders,
   type TextResponse
-} from '../../index.js'
+} from '../../index.ts'
 
 function exampleAtom(responseBody: string): TextResponse {
   return createTextResponse(responseBody, {
diff --git a/core/test/loader/json-feed.test.ts b/core/test/loader/json-feed.test.ts
index 52fb7ea6..e066484a 100644
--- a/core/test/loader/json-feed.test.ts
+++ b/core/test/loader/json-feed.test.ts
@@ -1,4 +1,4 @@
-import '../dom-parser.js'
+import '../dom-parser.ts'
 
 import { spyOn } from 'nanospy'
 import { deepStrictEqual, equal } from 'node:assert'
@@ -10,7 +10,7 @@ import {
   createTextResponse,
   loaders,
   type TextResponse
-} from '../../index.js'
+} from '../../index.ts'
 
 function exampleJson(json: object | string): TextResponse {
   let string = typeof json === 'string' ? json : JSON.stringify(json)
diff --git a/core/test/loader/rss.test.ts b/core/test/loader/rss.test.ts
index 023429af..794b5f41 100644
--- a/core/test/loader/rss.test.ts
+++ b/core/test/loader/rss.test.ts
@@ -1,4 +1,4 @@
-import '../dom-parser.js'
+import '../dom-parser.ts'
 
 import { spyOn } from 'nanospy'
 import { deepStrictEqual, equal } from 'node:assert'
@@ -10,7 +10,7 @@ import {
   createTextResponse,
   loaders,
   type TextResponse
-} from '../../index.js'
+} from '../../index.ts'
 
 function exampleRss(responseBody: string): TextResponse {
   return createTextResponse(responseBody, {
diff --git a/core/test/not-found.test.ts b/core/test/not-found.test.ts
index 3f46a854..6a67029c 100644
--- a/core/test/not-found.test.ts
+++ b/core/test/not-found.test.ts
@@ -2,8 +2,8 @@ import { LoguxUndoError } from '@logux/client'
 import { equal } from 'node:assert'
 import { afterEach, beforeEach, test } from 'node:test'
 
-import { notFound, setBaseTestRoute } from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+import { notFound, setBaseTestRoute } from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 let listener: (e: { reason: Error }) => void
 
diff --git a/core/test/post.test.ts b/core/test/post.test.ts
index 8205234e..dc180f9e 100644
--- a/core/test/post.test.ts
+++ b/core/test/post.test.ts
@@ -13,8 +13,8 @@ import {
   loadPosts,
   type OriginPost,
   processOriginPost
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/posts-page.test.ts b/core/test/posts-page.test.ts
index 2b3ab825..84198da7 100644
--- a/core/test/posts-page.test.ts
+++ b/core/test/posts-page.test.ts
@@ -1,7 +1,7 @@
 import { deepStrictEqual } from 'node:assert'
 import { test } from 'node:test'
 
-import { createPostsPage, type OriginPost } from '../index.js'
+import { createPostsPage, type OriginPost } from '../index.ts'
 
 const POST1: OriginPost = {
   full: '1',
diff --git a/core/test/preview.test.ts b/core/test/preview.test.ts
index 2ba91d3b..30ba5a9c 100644
--- a/core/test/preview.test.ts
+++ b/core/test/preview.test.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { ensureLoaded } from '@logux/client'
 import { restoreAll, spyOn } from 'nanospy'
@@ -35,8 +35,8 @@ import {
   setPreviewCandidate,
   setPreviewUrl,
   testFeed
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/production.test.ts b/core/test/production.test.ts
index a49a180f..37c4c2ce 100644
--- a/core/test/production.test.ts
+++ b/core/test/production.test.ts
@@ -1,10 +1,10 @@
-import './environment.js'
+import './environment.ts'
 
 import { cleanStores } from 'nanostores'
 import { match } from 'node:assert'
 import { afterEach, test } from 'node:test'
 
-import { client, userId } from '../index.js'
+import { client, userId } from '../index.ts'
 
 global.WebSocket = function () {} as any
 
diff --git a/core/test/refresh.test.ts b/core/test/refresh.test.ts
index 38593883..09d11f29 100644
--- a/core/test/refresh.test.ts
+++ b/core/test/refresh.test.ts
@@ -22,8 +22,8 @@ import {
   refreshStatistics,
   stopRefreshing,
   testFeed
-} from '../index.js'
-import { cleanClientTest, createPromise, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, createPromise, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   mockRequest()
diff --git a/core/test/request.test.ts b/core/test/request.test.ts
index d581541e..25fb8b6e 100644
--- a/core/test/request.test.ts
+++ b/core/test/request.test.ts
@@ -8,7 +8,7 @@ import {
   mockRequest,
   request,
   setRequestMethod
-} from '../index.js'
+} from '../index.ts'
 
 afterEach(() => {
   setRequestMethod(fetch)
diff --git a/core/test/router.test.ts b/core/test/router.test.ts
index eea688f7..fc2924b8 100644
--- a/core/test/router.test.ts
+++ b/core/test/router.test.ts
@@ -18,8 +18,8 @@ import {
   testFeed,
   testPost,
   userId
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/settings.test.ts b/core/test/settings.test.ts
index 17c18ce2..4fd07f1e 100644
--- a/core/test/settings.test.ts
+++ b/core/test/settings.test.ts
@@ -8,8 +8,8 @@ import {
   signOut,
   theme,
   userId
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from '../test/utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from '../test/utils.ts'
 
 let restarts = 0
 
diff --git a/core/test/slow.test.ts b/core/test/slow.test.ts
index cd7cebb4..21c81d04 100644
--- a/core/test/slow.test.ts
+++ b/core/test/slow.test.ts
@@ -21,8 +21,8 @@ import {
   slowPosts,
   testFeed,
   testPost
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/two-steps.test.ts b/core/test/two-steps.test.ts
index 5ef52b67..3e2cd4b7 100644
--- a/core/test/two-steps.test.ts
+++ b/core/test/two-steps.test.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import { deepStrictEqual, strictEqual } from 'node:assert'
 import { afterEach, beforeEach, test } from 'node:test'
@@ -20,8 +20,8 @@ import {
   setPreviewUrl,
   testFeed,
   testPost
-} from '../index.js'
-import { cleanClientTest, enableClientTest } from './utils.js'
+} from '../index.ts'
+import { cleanClientTest, enableClientTest } from './utils.ts'
 
 beforeEach(() => {
   enableClientTest()
diff --git a/core/test/utils.ts b/core/test/utils.ts
index 85791ea6..f945ef27 100644
--- a/core/test/utils.ts
+++ b/core/test/utils.ts
@@ -14,7 +14,7 @@ import {
   setBaseTestRoute,
   setupEnvironment,
   userId
-} from '../index.js'
+} from '../index.ts'
 
 export function enableClientTest(env: Partial<EnvironmentAndStore> = {}): void {
   setupEnvironment({ ...getTestEnvironment(), ...env })
diff --git a/core/two-steps.ts b/core/two-steps.ts
index 7d18fe22..9773d3ca 100644
--- a/core/two-steps.ts
+++ b/core/two-steps.ts
@@ -1,6 +1,6 @@
 import { atom } from 'nanostores'
 
-import { backRoute } from './router.js'
+import { backRoute } from './router.ts'
 
 export let secondStep = atom<boolean>(false)
 
diff --git a/loader-tests/check-opml.ts b/loader-tests/check-opml.ts
index 6999c530..b422fe57 100644
--- a/loader-tests/check-opml.ts
+++ b/loader-tests/check-opml.ts
@@ -12,7 +12,7 @@ import {
   isString,
   type LoaderTestFeed as OpmlFeed,
   readText
-} from './utils.js'
+} from './utils.ts'
 
 async function parseFeedsFromFile(path: string): Promise<OpmlFeed[]> {
   if (!path.endsWith('.opml') && !path.endsWith('.xml')) {
diff --git a/loader-tests/home.ts b/loader-tests/home.ts
index 4c56f6f0..00f90893 100644
--- a/loader-tests/home.ts
+++ b/loader-tests/home.ts
@@ -1,4 +1,4 @@
-import { createCLI, enableTestClient, findRSSfromHome } from './utils.js'
+import { createCLI, enableTestClient, findRSSfromHome } from './utils.ts'
 
 let cli = createCLI(
   'Debug feed search with specific feed',
diff --git a/loader-tests/package.json b/loader-tests/package.json
index d9bf9162..02599908 100644
--- a/loader-tests/package.json
+++ b/loader-tests/package.json
@@ -7,17 +7,16 @@
     "pnpm": "^9.0.0"
   },
   "scripts": {
-    "check-opml": "tsx check-opml.ts",
+    "check-opml": "../scripts/tsnode check-opml.ts",
     "test": "node --run test:loaders",
-    "url": "tsx url.ts",
-    "home": "tsx home.ts",
-    "test:loaders": "tsx test-loaders.ts"
+    "url": "../scripts/tsnode url.ts",
+    "home": "../scripts/tsnode home.ts",
+    "test:loaders": "../scripts/tsnode test-loaders.ts"
   },
   "devDependencies": {
     "@slowreader/core": "link:../core",
     "jsdom": "24.1.1",
     "nanostores": "0.11.2",
-    "tsx": "4.16.5",
     "yaml": "2.5.0"
   }
 }
diff --git a/loader-tests/test-loaders.ts b/loader-tests/test-loaders.ts
index 7a2f95a7..a6b50322 100644
--- a/loader-tests/test-loaders.ts
+++ b/loader-tests/test-loaders.ts
@@ -11,7 +11,7 @@ import {
   initializeProgressBar,
   type LoaderTestFeed,
   readText
-} from './utils.js'
+} from './utils.ts'
 
 const FEEDS = join(import.meta.dirname, 'feeds.yml')
 
diff --git a/loader-tests/url.ts b/loader-tests/url.ts
index cdeb65bc..48d31ece 100644
--- a/loader-tests/url.ts
+++ b/loader-tests/url.ts
@@ -1,4 +1,4 @@
-import { createCLI, enableTestClient, fetchAndParsePosts } from './utils.js'
+import { createCLI, enableTestClient, fetchAndParsePosts } from './utils.ts'
 
 let cli = createCLI(
   'Debug post loading with specific feed',
diff --git a/loader-tests/utils.ts b/loader-tests/utils.ts
index 27a2addf..2bfcbe44 100644
--- a/loader-tests/utils.ts
+++ b/loader-tests/utils.ts
@@ -1,4 +1,4 @@
-import './dom-parser.js'
+import './dom-parser.ts'
 
 import {
   createDownloadTask,
diff --git a/nano-staged.json b/nano-staged.json
index f570b75f..0d5e8761 100644
--- a/nano-staged.json
+++ b/nano-staged.json
@@ -3,11 +3,11 @@
   "*.css": "stylelint --fix",
   "*.svelte": ["prettier --write", "stylelint --fix"],
   "*.svg": "svgo",
-  ".devcontainer/Dockerfile": "tsx ./scripts/check-versions.ts",
-  ".node-version": "tsx ./scripts/check-versions.ts",
-  "package.json": "tsx ./scripts/check-versions.ts",
-  "*/package.json": "tsx ./scripts/check-versions.ts",
-  "*/Dockerfile": "tsx ./scripts/check-versions.ts",
-  "*.test.ts": "tsx ./scripts/check-focused-tests.ts",
-  "core/messages/*/en.ts": "tsx ./scripts/check-messages.ts"
+  ".devcontainer/Dockerfile": "./scripts/tsnode ./scripts/check-versions.ts",
+  ".node-version": "./scripts/tsnode ./scripts/check-versions.ts",
+  "package.json": "./scripts/tsnode ./scripts/check-versions.ts",
+  "*/package.json": "./scripts/tsnode ./scripts/check-versions.ts",
+  "*/Dockerfile": "./scripts/tsnode ./scripts/check-versions.ts",
+  "*.test.ts": "./scripts/tsnode ./scripts/check-focused-tests.ts",
+  "core/messages/*/en.ts": "./scripts/tsnode ./scripts/check-messages.ts"
 }
diff --git a/package.json b/package.json
index 65c574e9..6171870e 100644
--- a/package.json
+++ b/package.json
@@ -14,18 +14,18 @@
     "format": "pnpm run -r --include-workspace-root /^format:/",
     "clean": "pnpm run -r --include-workspace-root /^clean:/",
     "build": "pnpm run -r build",
-    "update-env": "tsx ./scripts/update-env.ts",
+    "update-env": "./scripts/tsnode ./scripts/update-env.ts",
     "format:prettier": "prettier -w **/*.{js,ts,html,md,cjs,json} *.{js,json,md}",
     "test:js": "eslint .",
     "test:types": "svelte-check",
     "test:audit": "pnpm audit --prod",
-    "test:focused": "tsx ./scripts/check-focused-tests.ts",
-    "test:messages": "tsx ./scripts/check-messages.ts",
-    "test:versions": "tsx ./scripts/check-versions.ts",
+    "test:focused": "./scripts/tsnode ./scripts/check-focused-tests.ts",
+    "test:messages": "./scripts/tsnode ./scripts/check-messages.ts",
+    "test:versions": "./scripts/tsnode ./scripts/check-versions.ts",
     "test:markdown": "remark . --frail",
     "test:format": "prettier --check **/*.{js,ts,html,md,cjs,json} *.{js,json,md}",
-    "check-opml": "tsx loader-tests/check-opml.ts",
-    "test-loaders": "tsx loader-tests/test-loaders.ts loader-tests/feeds.yml",
+    "check-opml": "./scripts/tsnode loader-tests/check-opml.ts",
+    "test-loaders": "./scripts/tsnode loader-tests/test-loaders.ts loader-tests/feeds.yml",
     "prepare": "husky"
   },
   "workspaces": [
@@ -40,7 +40,7 @@
     "@logux/eslint-config": "53.3.0",
     "@types/node": "22.1.0",
     "@types/ws": "8.5.12",
-    "better-node-test": "0.5.1",
+    "better-node-test": "0.6.0",
     "eslint": "9.8.0",
     "eslint-plugin-svelte": "^2.43.0",
     "husky": "^9.1.4",
@@ -64,7 +64,6 @@
     "svelte": "4.2.18",
     "svelte-check": "3.8.5",
     "svgo": "3.3.2",
-    "tsx": "4.16.5",
     "typescript": "5.5.4"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 4da7d69a..f5578fc5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -18,8 +18,8 @@ importers:
         specifier: 8.5.12
         version: 8.5.12
       better-node-test:
-        specifier: 0.5.1
-        version: 0.5.1
+        specifier: 0.6.0
+        version: 0.6.0
       eslint:
         specifier: 9.8.0
         version: 9.8.0
@@ -85,13 +85,10 @@ importers:
         version: 4.2.18
       svelte-check:
         specifier: 3.8.5
-        version: 3.8.5(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)
+        version: 3.8.5(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)
       svgo:
         specifier: 3.3.2
         version: 3.3.2
-      tsx:
-        specifier: 4.16.5
-        version: 4.16.5
       typescript:
         specifier: 5.5.4
         version: 5.5.4
@@ -138,8 +135,8 @@ importers:
         specifier: 21.1.7
         version: 21.1.7
       better-node-test:
-        specifier: 0.5.1
-        version: 0.5.1
+        specifier: 0.6.0
+        version: 0.6.0
       c8:
         specifier: 10.1.2
         version: 10.1.2
@@ -161,9 +158,6 @@ importers:
       nanostores:
         specifier: 0.11.2
         version: 0.11.2
-      tsx:
-        specifier: 4.16.5
-        version: 4.16.5
       yaml:
         specifier: 2.5.0
         version: 2.5.0
@@ -175,14 +169,11 @@ importers:
         version: 0.23.0
     devDependencies:
       better-node-test:
-        specifier: 0.5.1
-        version: 0.5.1
+        specifier: 0.6.0
+        version: 0.6.0
       c8:
         specifier: 10.1.2
         version: 10.1.2
-      tsx:
-        specifier: 4.16.5
-        version: 4.16.5
 
   server:
     dependencies:
@@ -192,10 +183,6 @@ importers:
       '@slowreader/api':
         specifier: link:../api
         version: link:../api
-    devDependencies:
-      tsx:
-        specifier: 4.16.5
-        version: 4.16.5
 
   web:
     dependencies:
@@ -252,10 +239,7 @@ importers:
         version: 4.2.18
       svelte-preprocess:
         specifier: 6.0.2
-        version: 6.0.2(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
-      tsx:
-        specifier: 4.16.5
-        version: 4.16.5
+        version: 6.0.2(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
       vite:
         specifier: 5.4.0
         version: 5.4.0(@types/node@22.1.0)
@@ -280,7 +264,7 @@ importers:
         version: 8.2.8(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)
       '@storybook/svelte-vite':
         specifier: 8.2.8
-        version: 8.2.8(@babel/core@7.25.2)(@sveltejs/vite-plugin-svelte@3.1.1(svelte@4.2.18)(vite@5.4.0(@types/node@22.1.0)))(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)(typescript@5.5.4)(vite@5.4.0(@types/node@22.1.0))
+        version: 8.2.8(@babel/core@7.25.2)(@sveltejs/vite-plugin-svelte@3.1.1(svelte@4.2.18)(vite@5.4.0(@types/node@22.1.0)))(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)(typescript@5.5.4)(vite@5.4.0(@types/node@22.1.0))
       '@storybook/types':
         specifier: ^8.2.8
         version: 8.2.8(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))
@@ -288,8 +272,8 @@ importers:
         specifier: 2.0.0
         version: 2.0.0(stylelint@16.8.1(typescript@5.5.4))
       better-node-test:
-        specifier: 0.5.1
-        version: 0.5.1
+        specifier: 0.6.0
+        version: 0.6.0
       browserslist:
         specifier: 4.23.3
         version: 4.23.3
@@ -2076,8 +2060,8 @@ packages:
   base64-js@1.5.1:
     resolution: {integrity: sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA==}
 
-  better-node-test@0.5.1:
-    resolution: {integrity: sha512-L5iVFSXrX+hCJ4OItXGzDQ+HMAPUcoXu6Zwnlha7mtkoBu3sRZb4PtkOFJg/mJnIerKfbgRl4f4qDqcDLfM5rA==}
+  better-node-test@0.6.0:
+    resolution: {integrity: sha512-ML+qpsuaL4KgQe9vmD/dDLeCTLHGuqy/N6p4jFRIscoLdznucd3l75gBQznoiq0LrgRa6Gs70RU00Bl4LR+giQ==}
     engines: {node: ^18.19.0 || >=20.0.0}
     hasBin: true
 
@@ -5089,11 +5073,6 @@ packages:
   tslib@2.6.3:
     resolution: {integrity: sha512-xNvxJEOUiWPGhUuUdQgAJPKOOJfGnIyKySOc09XkKsgdUV/3E2zvwZYdejjmRgPCgcym1juLH3226yA7sEFJKQ==}
 
-  tsx@4.16.5:
-    resolution: {integrity: sha512-ArsiAQHEW2iGaqZ8fTA1nX0a+lN5mNTyuGRRO6OW3H/Yno1y9/t1f9YOI1Cfoqz63VAthn++ZYcbDP7jPflc+A==}
-    engines: {node: '>=18.0.0'}
-    hasBin: true
-
   type-check@0.4.0:
     resolution: {integrity: sha512-XleUoc9uwGXqjWwXaUTZAmzMcFZ5858QA2vvx1Ur5xIcixXIP+8LnFDgRplU30us6teqdlskFfu+ae4K79Ooew==}
     engines: {node: '>= 0.8.0'}
@@ -6958,7 +6937,7 @@ snapshots:
     dependencies:
       storybook: 8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2))
 
-  '@storybook/svelte-vite@8.2.8(@babel/core@7.25.2)(@sveltejs/vite-plugin-svelte@3.1.1(svelte@4.2.18)(vite@5.4.0(@types/node@22.1.0)))(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)(typescript@5.5.4)(vite@5.4.0(@types/node@22.1.0))':
+  '@storybook/svelte-vite@8.2.8(@babel/core@7.25.2)(@sveltejs/vite-plugin-svelte@3.1.1(svelte@4.2.18)(vite@5.4.0(@types/node@22.1.0)))(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)(typescript@5.5.4)(vite@5.4.0(@types/node@22.1.0))':
     dependencies:
       '@storybook/builder-vite': 8.2.8(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(typescript@5.5.4)(vite@5.4.0(@types/node@22.1.0))
       '@storybook/svelte': 8.2.8(storybook@8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2)))(svelte@4.2.18)
@@ -6966,7 +6945,7 @@ snapshots:
       magic-string: 0.30.11
       storybook: 8.2.8(@babel/preset-env@7.25.3(@babel/core@7.25.2))
       svelte: 4.2.18
-      svelte-preprocess: 5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
+      svelte-preprocess: 5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
       sveltedoc-parser: 4.2.1
       ts-dedent: 2.2.0
       vite: 5.4.0(@types/node@22.1.0)
@@ -7474,7 +7453,7 @@ snapshots:
 
   base64-js@1.5.1: {}
 
-  better-node-test@0.5.1: {}
+  better-node-test@0.6.0: {}
 
   binary-extensions@2.3.0: {}
 
@@ -9956,13 +9935,12 @@ snapshots:
     optionalDependencies:
       postcss: 8.4.41
 
-  postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0):
+  postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0):
     dependencies:
       lilconfig: 3.1.2
     optionalDependencies:
       jiti: 1.21.6
       postcss: 8.4.41
-      tsx: 4.16.5
       yaml: 2.5.0
     optional: true
 
@@ -10753,14 +10731,14 @@ snapshots:
 
   supports-preserve-symlinks-flag@1.0.0: {}
 
-  svelte-check@3.8.5(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18):
+  svelte-check@3.8.5(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18):
     dependencies:
       '@jridgewell/trace-mapping': 0.3.25
       chokidar: 3.6.0
       picocolors: 1.0.1
       sade: 1.8.1
       svelte: 4.2.18
-      svelte-preprocess: 5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
+      svelte-preprocess: 5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4)
       typescript: 5.5.4
     transitivePeerDependencies:
       - '@babel/core'
@@ -10787,7 +10765,7 @@ snapshots:
     dependencies:
       svelte: 4.2.18
 
-  svelte-preprocess@5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4):
+  svelte-preprocess@5.1.4(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4):
     dependencies:
       '@types/pug': 2.0.10
       detect-indent: 6.1.0
@@ -10798,16 +10776,16 @@ snapshots:
     optionalDependencies:
       '@babel/core': 7.25.2
       postcss: 8.4.41
-      postcss-load-config: 6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0)
+      postcss-load-config: 6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0)
       typescript: 5.5.4
 
-  svelte-preprocess@6.0.2(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4):
+  svelte-preprocess@6.0.2(@babel/core@7.25.2)(postcss-load-config@6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0))(postcss@8.4.41)(svelte@4.2.18)(typescript@5.5.4):
     dependencies:
       svelte: 4.2.18
     optionalDependencies:
       '@babel/core': 7.25.2
       postcss: 8.4.41
-      postcss-load-config: 6.0.1(jiti@1.21.6)(postcss@8.4.41)(tsx@4.16.5)(yaml@2.5.0)
+      postcss-load-config: 6.0.1(jiti@1.21.6)(postcss@8.4.41)(yaml@2.5.0)
       typescript: 5.5.4
 
   svelte@4.2.18:
@@ -10939,13 +10917,6 @@ snapshots:
 
   tslib@2.6.3: {}
 
-  tsx@4.16.5:
-    dependencies:
-      esbuild: 0.21.5
-      get-tsconfig: 4.7.6
-    optionalDependencies:
-      fsevents: 2.3.3
-
   type-check@0.4.0:
     dependencies:
       prelude-ls: 1.2.1
diff --git a/proxy/index.ts b/proxy/index.ts
index f8c67150..c70722c9 100755
--- a/proxy/index.ts
+++ b/proxy/index.ts
@@ -1,6 +1,6 @@
 import { styleText } from 'node:util'
 
-import { createProxyServer } from './proxy.js'
+import { createProxyServer } from './proxy.ts'
 
 const PORT = process.env.PORT ?? 5284
 
diff --git a/proxy/package.json b/proxy/package.json
index cb52e0fb..a402ffd0 100644
--- a/proxy/package.json
+++ b/proxy/package.json
@@ -7,7 +7,7 @@
     "pnpm": "^9.0.0"
   },
   "scripts": {
-    "start": "tsx watch index.ts",
+    "start": "../scripts/tsnode --watch index.ts",
     "test": "FORCE_COLOR=1 pnpm run /^test:/",
     "build": "esbuild index.ts --bundle --platform=node --sourcemap --format=esm --outfile=dist/index.mjs",
     "production": "node --run build && ./scripts/run-image.sh",
@@ -19,8 +19,7 @@
     "esbuild": "0.23.0"
   },
   "devDependencies": {
-    "better-node-test": "0.5.1",
-    "c8": "10.1.2",
-    "tsx": "4.16.5"
+    "better-node-test": "0.6.0",
+    "c8": "10.1.2"
   }
 }
diff --git a/proxy/test/proxy.test.ts b/proxy/test/proxy.test.ts
index 0d6cd83b..54166a9f 100644
--- a/proxy/test/proxy.test.ts
+++ b/proxy/test/proxy.test.ts
@@ -5,7 +5,7 @@ import { after, test } from 'node:test'
 import { setTimeout } from 'node:timers/promises'
 import { URL } from 'node:url'
 
-import { createProxyServer } from '../proxy.js'
+import { createProxyServer } from '../proxy.ts'
 
 function getURL(server: Server): string {
   let port = (server.address() as AddressInfo).port
diff --git a/scripts/tsnode b/scripts/tsnode
new file mode 100755
index 00000000..4247ca7f
--- /dev/null
+++ b/scripts/tsnode
@@ -0,0 +1,4 @@
+#!/bin/bash
+# Shortcut to run Node.js with TS support and without experimental warnings
+
+node --experimental-strip-types --disable-warning=ExperimentalWarning $@
diff --git a/server/package.json b/server/package.json
index 08a4382a..39d9f938 100644
--- a/server/package.json
+++ b/server/package.json
@@ -7,13 +7,10 @@
     "pnpm": "^9.0.0"
   },
   "scripts": {
-    "start": "tsx watch index.ts"
+    "start": "../scripts/tsnode --watch index.ts"
   },
   "dependencies": {
     "@logux/server": "0.13.0",
     "@slowreader/api": "link:../api"
-  },
-  "devDependencies": {
-    "tsx": "4.16.5"
   }
 }
diff --git a/tsconfig.json b/tsconfig.json
index f2dea244..95817665 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,13 +1,14 @@
 {
   "compilerOptions": {
+    "allowImportingTsExtensions": true,
     "noUncheckedIndexedAccess": true,
     "verbatimModuleSyntax": true,
-    "moduleResolution": "node16",
+    "moduleResolution": "NodeNext",
     "esModuleInterop": true,
     "skipLibCheck": true,
     "allowJs": true,
     "target": "es2021",
-    "module": "node16",
+    "module": "NodeNext",
     "strict": true,
     "noEmit": true,
     "paths": {
diff --git a/web/.storybook/preview.ts b/web/.storybook/preview.ts
index 6f34db5c..e5636d18 100644
--- a/web/.storybook/preview.ts
+++ b/web/.storybook/preview.ts
@@ -1,5 +1,5 @@
-import '../main/browser.js'
-import '../stories/environment.js'
+import '../main/browser.ts'
+import '../stories/environment.ts'
 
 import '../main/index.css'
 
diff --git a/web/main/browser.ts b/web/main/browser.ts
index 781338ac..84c40570 100644
--- a/web/main/browser.ts
+++ b/web/main/browser.ts
@@ -9,7 +9,7 @@ import {
   startKeyUX
 } from 'keyux'
 
-import { locale } from '../stores/locale.js'
+import { locale } from '../stores/locale.ts'
 
 let root = document.documentElement
 let themeTag = document.querySelector('meta[name="theme-color"]')
@@ -56,5 +56,5 @@ startKeyUX(window, [
 ])
 
 window.addEventListener('load', async () => {
-  await import('./devtools.js')
+  await import('./devtools.ts')
 })
diff --git a/web/main/environment.ts b/web/main/environment.ts
index eb797300..c7f54ed7 100644
--- a/web/main/environment.ts
+++ b/web/main/environment.ts
@@ -10,8 +10,8 @@ import {
   setupEnvironment
 } from '@slowreader/core'
 
-import { locale } from '../stores/locale.js'
-import { openRoute, urlRouter } from '../stores/router.js'
+import { locale } from '../stores/locale.ts'
+import { openRoute, urlRouter } from '../stores/router.ts'
 
 enableWarnings()
 
diff --git a/web/main/index.ts b/web/main/index.ts
index c6812abd..11331105 100644
--- a/web/main/index.ts
+++ b/web/main/index.ts
@@ -1,5 +1,5 @@
-import './environment.js'
-import './browser.js'
+import './environment.ts'
+import './browser.ts'
 
 import './index.css'
 
diff --git a/web/package.json b/web/package.json
index 6b67f4df..660a8e4f 100644
--- a/web/package.json
+++ b/web/package.json
@@ -14,12 +14,12 @@
     "production": "node --run build && ./scripts/run-image.sh",
     "size": "node --run build:web && size-limit",
     "test:unit": "pnpm bnt",
-    "test:names": "tsx ./scripts/check-names.ts",
+    "test:names": "../scripts/tsnode ./scripts/check-names.ts",
     "test:css": "stylelint **/*.css **/*.svelte",
     "test:build": "node --run build && size-limit",
-    "build:routes": "tsx ./scripts/export-routes.ts",
+    "build:routes": "../scripts/tsnode ./scripts/export-routes.ts",
     "build:visual": "NODE_ENV=test storybook build",
-    "build:web": "vite build && tsx ./scripts/clean-css.ts && tsx scripts/generate-csp.ts",
+    "build:web": "vite build && ../scripts/tsnode ./scripts/clean-css.ts && ../scripts/tsnode scripts/generate-csp.ts",
     "format:stylelint": "stylelint --fix **/*.{css,svelte}",
     "clean:build": "rm -rf dist"
   },
@@ -42,7 +42,6 @@
     "rollup": "4.20.0",
     "svelte": "4.2.18",
     "svelte-preprocess": "6.0.2",
-    "tsx": "4.16.5",
     "vite": "5.4.0"
   },
   "devDependencies": {
@@ -55,7 +54,7 @@
     "@storybook/svelte-vite": "8.2.8",
     "@storybook/types": "^8.2.8",
     "@stylistic/stylelint-config": "2.0.0",
-    "better-node-test": "0.5.1",
+    "better-node-test": "0.6.0",
     "browserslist": "4.23.3",
     "postcss-html": "1.7.0",
     "postcss-nesting": "13.0.0",
diff --git a/web/pages/fast.svelte b/web/pages/fast.svelte
index 4a487781..334ce1aa 100644
--- a/web/pages/fast.svelte
+++ b/web/pages/fast.svelte
@@ -10,7 +10,7 @@
   } from '@slowreader/core'
   import { onMount, tick } from 'svelte'
 
-  import { getURL } from '../stores/router.js'
+  import { getURL } from '../stores/router.ts'
   import Button from '../ui/button.svelte'
   import Loader from '../ui/loader.svelte'
   import PostCard from '../ui/post-card.svelte'
diff --git a/web/pages/feeds/add.svelte b/web/pages/feeds/add.svelte
index 9f1c7344..1557ddfd 100644
--- a/web/pages/feeds/add.svelte
+++ b/web/pages/feeds/add.svelte
@@ -14,7 +14,7 @@
     previewMessages as t
   } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import Button from '../../ui/button.svelte'
   import CardLink from '../../ui/card-link.svelte'
   import CardLinks from '../../ui/card-links.svelte'
diff --git a/web/pages/feeds/categories.svelte b/web/pages/feeds/categories.svelte
index a20ba3de..56871760 100644
--- a/web/pages/feeds/categories.svelte
+++ b/web/pages/feeds/categories.svelte
@@ -11,7 +11,7 @@
     organizeMessages as t
   } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import Button from '../../ui/button.svelte'
   import CardLink from '../../ui/card-link.svelte'
   import CardLinks from '../../ui/card-links.svelte'
diff --git a/web/pages/feeds/export.svelte b/web/pages/feeds/export.svelte
index 8ff02e63..6ada9835 100644
--- a/web/pages/feeds/export.svelte
+++ b/web/pages/feeds/export.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { exportMessages as t } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import CardLink from '../../ui/card-link.svelte'
   import CardLinks from '../../ui/card-links.svelte'
   import TwoStepsPage from '../../ui/two-steps-page.svelte'
diff --git a/web/pages/slow.svelte b/web/pages/slow.svelte
index 6ab78a57..54ccf19e 100644
--- a/web/pages/slow.svelte
+++ b/web/pages/slow.svelte
@@ -8,7 +8,7 @@
     totalSlowPosts
   } from '@slowreader/core'
 
-  import { getURL } from '../stores/router.js'
+  import { getURL } from '../stores/router.ts'
   import Loader from '../ui/loader.svelte'
   import PaginationBar from '../ui/pagination-bar.svelte'
   import PostCard from '../ui/post-card.svelte'
diff --git a/web/scripts/clean-css.ts b/web/scripts/clean-css.ts
index f2177f0a..953436f1 100755
--- a/web/scripts/clean-css.ts
+++ b/web/scripts/clean-css.ts
@@ -8,8 +8,8 @@ import { extname, join } from 'node:path'
 import { styleText } from 'node:util'
 import postcss from 'postcss'
 
-import { rootsMerger } from '../postcss/roots-merger.js'
-import { getVarsCleanerError, varsCleaner } from '../postcss/vars-cleaner.js'
+import { rootsMerger } from '../postcss/roots-merger.ts'
+import { getVarsCleanerError, varsCleaner } from '../postcss/vars-cleaner.ts'
 
 function printError(message: string): void {
   process.stderr.write(styleText('red', message) + '\n')
diff --git a/web/scripts/export-routes.ts b/web/scripts/export-routes.ts
index cccd37de..2072a1b0 100644
--- a/web/scripts/export-routes.ts
+++ b/web/scripts/export-routes.ts
@@ -5,7 +5,7 @@
 import { writeFileSync } from 'node:fs'
 import { join } from 'node:path'
 
-import { pathRouter } from '../stores/router.js'
+import { pathRouter } from '../stores/router.ts'
 
 const ROUTES = join(import.meta.dirname, '../routes.regexp')
 
diff --git a/web/stories/pages/posts/fast.stories.svelte b/web/stories/pages/posts/fast.stories.svelte
index 5e9dd04d..12b8498b 100644
--- a/web/stories/pages/posts/fast.stories.svelte
+++ b/web/stories/pages/posts/fast.stories.svelte
@@ -3,7 +3,7 @@
 
   import Fast from '../../../pages/fast.svelte'
   import Scene from '../../scene.svelte'
-  import { MOCKED_FAST_FEED, MOCKED_POSTS } from './mocks.js'
+  import { MOCKED_FAST_FEED, MOCKED_POSTS } from './mocks.ts'
 
   export const meta = {
     component: Fast,
diff --git a/web/stories/pages/posts/slow.stories.svelte b/web/stories/pages/posts/slow.stories.svelte
index e22d56c4..d771dcef 100644
--- a/web/stories/pages/posts/slow.stories.svelte
+++ b/web/stories/pages/posts/slow.stories.svelte
@@ -3,7 +3,7 @@
 
   import Slow from '../../../pages/slow.svelte'
   import Scene from '../../scene.svelte'
-  import { MOCKED_POSTS } from './mocks.js'
+  import { MOCKED_POSTS } from './mocks.ts'
 
   export const meta = {
     component: Slow,
diff --git a/web/stories/scene.svelte b/web/stories/scene.svelte
index 98a6f90e..a26fb6ad 100644
--- a/web/stories/scene.svelte
+++ b/web/stories/scene.svelte
@@ -43,13 +43,13 @@
   import { cleanStores } from 'nanostores'
   import { onMount } from 'svelte'
 
-  import { forceSet } from '../../core/lib/stores.js'
+  import { forceSet } from '../../core/lib/stores.ts'
   import {
     baseRouter,
     type PreparedResponse,
     prepareResponses,
     setNetworkType
-  } from './environment.js'
+  } from './environment.ts'
 
   const DEFAULT_NETWORK: ReturnType<NetworkTypeDetector> = {
     saveData: false,
diff --git a/web/stories/ui/button.stories.svelte b/web/stories/ui/button.stories.svelte
index d41d77c5..54968b17 100644
--- a/web/stories/ui/button.stories.svelte
+++ b/web/stories/ui/button.stories.svelte
@@ -12,7 +12,7 @@
   import { Story } from '@storybook/addon-svelte-csf'
   import { onMount } from 'svelte'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import CardActions from '../../ui/card-actions.svelte'
   import Card from '../../ui/card.svelte'
   import Scene from '../scene.svelte'
diff --git a/web/test/roots-merger.test.ts b/web/test/roots-merger.test.ts
index 780fa471..5303a976 100644
--- a/web/test/roots-merger.test.ts
+++ b/web/test/roots-merger.test.ts
@@ -2,7 +2,7 @@ import { equal } from 'node:assert'
 import { test } from 'node:test'
 import postcss from 'postcss'
 
-import { rootsMerger } from '../postcss/roots-merger.js'
+import { rootsMerger } from '../postcss/roots-merger.ts'
 
 function run(input: string, output: string): void {
   let result = postcss([rootsMerger]).process(input, { from: undefined })
diff --git a/web/test/vars-cleaner.test.ts b/web/test/vars-cleaner.test.ts
index f4fe5a32..2d927d07 100644
--- a/web/test/vars-cleaner.test.ts
+++ b/web/test/vars-cleaner.test.ts
@@ -6,7 +6,7 @@ import {
   getVarsCleanerError,
   resetCleanerGlobals,
   varsCleaner
-} from '../postcss/vars-cleaner.js'
+} from '../postcss/vars-cleaner.ts'
 
 function run(input: string, output: string): string | undefined {
   let result = postcss([varsCleaner]).process(input, { from: undefined })
diff --git a/web/ui/navbar/fast.svelte b/web/ui/navbar/fast.svelte
index fb068213..29b98dbe 100644
--- a/web/ui/navbar/fast.svelte
+++ b/web/ui/navbar/fast.svelte
@@ -6,7 +6,7 @@
     commonMessages as t
   } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import Loader from '../loader.svelte'
   import NavbarItem from './item.svelte'
 
diff --git a/web/ui/navbar/index.svelte b/web/ui/navbar/index.svelte
index 08becf8a..a3e0b172 100644
--- a/web/ui/navbar/index.svelte
+++ b/web/ui/navbar/index.svelte
@@ -13,7 +13,7 @@
   } from '@slowreader/core'
   import { onMount } from 'svelte'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import Hotkey from '../hotkey.svelte'
   import Icon from '../icon.svelte'
   import NavbarFireplace from '../navbar/fireplace.svelte'
diff --git a/web/ui/navbar/other.svelte b/web/ui/navbar/other.svelte
index e9b18653..c16464e6 100644
--- a/web/ui/navbar/other.svelte
+++ b/web/ui/navbar/other.svelte
@@ -11,7 +11,7 @@
   } from '@mdi/js'
   import { hasFeeds, router, navbarMessages as t } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import NavbarCategory from './category.svelte'
   import NavbarItem from './item.svelte'
 </script>
diff --git a/web/ui/navbar/slow.svelte b/web/ui/navbar/slow.svelte
index 2b200b32..ede4f5f6 100644
--- a/web/ui/navbar/slow.svelte
+++ b/web/ui/navbar/slow.svelte
@@ -7,7 +7,7 @@
     commonMessages as t
   } from '@slowreader/core'
 
-  import { getURL } from '../../stores/router.js'
+  import { getURL } from '../../stores/router.ts'
   import Loader from '../loader.svelte'
   import NavbarCategory from './category.svelte'
   import NavbarItem from './item.svelte'
diff --git a/web/ui/two-steps-page.svelte b/web/ui/two-steps-page.svelte
index 3df6b65c..7aad2613 100644
--- a/web/ui/two-steps-page.svelte
+++ b/web/ui/two-steps-page.svelte
@@ -3,7 +3,7 @@
   import { backRoute, backToFirstStep } from '@slowreader/core'
   import { onMount } from 'svelte'
 
-  import { getURL } from '../stores/router.js'
+  import { getURL } from '../stores/router.ts'
   import Button from './button.svelte'
 
   export let title: string