diff --git a/apps/web/app/(app)/[emailAccountId]/assistant/BulkRunRules.tsx b/apps/web/app/(app)/[emailAccountId]/assistant/BulkRunRules.tsx
index 6b30361f37..26485b0a60 100644
--- a/apps/web/app/(app)/[emailAccountId]/assistant/BulkRunRules.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/assistant/BulkRunRules.tsx
@@ -176,7 +176,10 @@ async function onRun(
         q,
       };
       const res = await fetchWithAccount({
-        url: `/api/threads?${new URLSearchParams(query as any).toString()}`,
+        url: `/api/threads?${
+          // biome-ignore lint/suspicious/noExplicitAny: simplest
+          new URLSearchParams(query as any).toString()
+        }`,
         emailAccountId,
       });
       const data: ThreadsResponse = await res.json();
diff --git a/apps/web/app/(app)/[emailAccountId]/assistant/RuleForm.tsx b/apps/web/app/(app)/[emailAccountId]/assistant/RuleForm.tsx
index 725a261e5d..617419a08a 100644
--- a/apps/web/app/(app)/[emailAccountId]/assistant/RuleForm.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/assistant/RuleForm.tsx
@@ -5,6 +5,7 @@ import { useRouter } from "next/navigation";
 import Link from "next/link";
 import {
   type FieldError,
+  type FieldErrors,
   type SubmitHandler,
   useFieldArray,
   useForm,
@@ -132,6 +133,7 @@ export function RuleForm({
   alwaysEditMode?: boolean;
   onSuccess?: () => void;
   isDialog?: boolean;
+  // biome-ignore lint/suspicious/noExplicitAny: lazy
   mutate?: (data?: any, options?: any) => void;
   onCancel?: () => void;
 }) {
@@ -1033,7 +1035,7 @@ function ActionCard({
   watch: ReturnType<typeof useForm<CreateRuleBody>>["watch"];
   setValue: ReturnType<typeof useForm<CreateRuleBody>>["setValue"];
   control: ReturnType<typeof useForm<CreateRuleBody>>["control"];
-  errors: any;
+  errors: FieldErrors<CreateRuleBody>;
   userLabels: EmailLabel[];
   isLoading: boolean;
   mutate: () => void;
@@ -1375,7 +1377,10 @@ function ActionCard({
               {errors?.actions?.[index]?.delayInMinutes && (
                 <div className="mt-2">
                   <ErrorMessage
-                    message={errors.actions?.[index]?.delayInMinutes?.message}
+                    message={
+                      errors.actions?.[index]?.delayInMinutes?.message ||
+                      "Invalid delay value"
+                    }
                   />
                 </div>
               )}
diff --git a/apps/web/app/(app)/[emailAccountId]/assistant/rule/[ruleId]/error.tsx b/apps/web/app/(app)/[emailAccountId]/assistant/rule/[ruleId]/error.tsx
index 6c7d61f43b..08f188e456 100644
--- a/apps/web/app/(app)/[emailAccountId]/assistant/rule/[ruleId]/error.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/assistant/rule/[ruleId]/error.tsx
@@ -4,7 +4,11 @@ import * as Sentry from "@sentry/nextjs";
 import { useEffect } from "react";
 import { ErrorDisplay } from "@/components/ErrorDisplay";
 
-export default function ErrorBoundary({ error }: any) {
+export default function ErrorBoundary({
+  error,
+}: {
+  error: Error & { digest?: string };
+}) {
   useEffect(() => {
     Sentry.captureException(error);
   }, [error]);
diff --git a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkActions.tsx b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkActions.tsx
index d823ed9e6a..3370dcb0af 100644
--- a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkActions.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkActions.tsx
@@ -22,6 +22,7 @@ export function BulkActions({
   mutate,
 }: {
   selected: Map<string, boolean>;
+  // biome-ignore lint/suspicious/noExplicitAny: lazy
   mutate: () => Promise<any>;
 }) {
   const posthog = usePostHog();
diff --git a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkUnsubscribeSection.tsx b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkUnsubscribeSection.tsx
index a61babe39a..15a5346be0 100644
--- a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkUnsubscribeSection.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/BulkUnsubscribeSection.tsx
@@ -107,6 +107,7 @@ export function BulkUnsubscribe() {
     includeMissingUnsubscribe: true,
     ...getDateRangeParams(dateRange),
   };
+  // biome-ignore lint/suspicious/noExplicitAny: simplest
   const urlParams = new URLSearchParams(params as any);
   const { data, isLoading, error, mutate } = useSWR<
     NewsletterStatsResponse,
diff --git a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/common.tsx b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/common.tsx
index 372b7845e0..751c695ab2 100644
--- a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/common.tsx
+++ b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/common.tsx
@@ -18,6 +18,7 @@ import {
   TrashIcon,
 } from "lucide-react";
 import { type PostHog, usePostHog } from "posthog-js/react";
+import type { UserResponse } from "@/app/api/user/me/route";
 import { Button } from "@/components/ui/button";
 import { ButtonLoader } from "@/components/Loading";
 import { Tooltip } from "@/components/Tooltip";
@@ -69,7 +70,7 @@ export function ActionCell<T extends Row>({
   item: T;
   hasUnsubscribeAccess: boolean;
   mutate: () => Promise<void>;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   onOpenNewsletter: (row: T) => void;
   selected: boolean;
   labels: EmailLabel[];
@@ -159,7 +160,7 @@ function UnsubscribeButton<T extends Row>({
   item: T;
   hasUnsubscribeAccess: boolean;
   mutate: () => Promise<void>;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   posthog: PostHog;
   emailAccountId: string;
 }) {
@@ -223,7 +224,7 @@ function AutoArchiveButton<T extends Row>({
   hasUnsubscribeAccess: boolean;
   mutate: () => Promise<void>;
   posthog: PostHog;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   labels: EmailLabel[];
   emailAccountId: string;
 }) {
diff --git a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/hooks.ts b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/hooks.ts
index 1ecddf1f40..fdbeefeeab 100644
--- a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/hooks.ts
+++ b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/hooks.ts
@@ -15,6 +15,7 @@ import type { Row } from "@/app/(app)/[emailAccountId]/bulk-unsubscribe/types";
 import type { GetThreadsResponse } from "@/app/api/threads/basic/route";
 import { isDefined } from "@/utils/types";
 import { fetchWithAccount } from "@/utils/fetch";
+import type { UserResponse } from "@/app/api/user/me/route";
 
 async function unsubscribeAndArchive({
   newsletterEmail,
@@ -24,7 +25,7 @@ async function unsubscribeAndArchive({
 }: {
   newsletterEmail: string;
   mutate: () => Promise<void>;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   emailAccountId: string;
 }) {
   await setNewsletterStatusAction(emailAccountId, {
@@ -53,7 +54,7 @@ export function useUnsubscribe<T extends Row>({
   hasUnsubscribeAccess: boolean;
   mutate: () => Promise<void>;
   posthog: PostHog;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
 }) {
   const [unsubscribeLoading, setUnsubscribeLoading] = useState(false);
 
@@ -112,9 +113,9 @@ export function useBulkUnsubscribe<T extends Row>({
   emailAccountId,
 }: {
   hasUnsubscribeAccess: boolean;
-  mutate: () => Promise<any>;
+  mutate: () => Promise<void>;
   posthog: PostHog;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   emailAccountId: string;
 }) {
   const [bulkUnsubscribeLoading, setBulkUnsubscribeLoading] = useState(false);
@@ -167,7 +168,7 @@ async function autoArchive({
   labelId: string | undefined;
   labelName: string | undefined;
   mutate: () => Promise<void>;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   emailAccountId: string;
 }) {
   await onAutoArchive({
@@ -200,9 +201,9 @@ export function useAutoArchive<T extends Row>({
 }: {
   item: T;
   hasUnsubscribeAccess: boolean;
-  mutate: () => Promise<any>;
+  mutate: () => Promise<void>;
   posthog: PostHog;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   emailAccountId: string;
 }) {
   const [autoArchiveLoading, setAutoArchiveLoading] = useState(false);
@@ -286,8 +287,8 @@ export function useBulkAutoArchive<T extends Row>({
   emailAccountId,
 }: {
   hasUnsubscribeAccess: boolean;
-  mutate: () => Promise<any>;
-  refetchPremium: () => Promise<any>;
+  mutate: () => Promise<void>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   emailAccountId: string;
 }) {
   const [bulkAutoArchiveLoading, setBulkAutoArchiveLoading] = useState(false);
@@ -337,7 +338,7 @@ export function useApproveButton<T extends Row>({
     hasUnsubscribeAccess: true,
     mutate,
     posthog,
-    refetchPremium: () => Promise.resolve(),
+    refetchPremium: () => Promise.resolve(undefined),
     emailAccountId,
   });
 
@@ -367,7 +368,7 @@ export function useBulkApprove<T extends Row>({
   posthog,
   emailAccountId,
 }: {
-  mutate: () => Promise<any>;
+  mutate: () => Promise<void>;
   posthog: PostHog;
   emailAccountId: string;
 }) {
@@ -467,7 +468,7 @@ export function useBulkArchive<T extends Row>({
   posthog,
   emailAccountId,
 }: {
-  mutate: () => Promise<any>;
+  mutate: () => Promise<void>;
   posthog: PostHog;
   emailAccountId: string;
 }) {
@@ -566,7 +567,7 @@ export function useBulkDelete<T extends Row>({
   posthog,
   emailAccountId,
 }: {
-  mutate: () => Promise<any>;
+  mutate: () => Promise<void>;
   posthog: PostHog;
   emailAccountId: string;
 }) {
@@ -600,8 +601,9 @@ export function useBulkUnsubscribeShortcuts<T extends Row>({
   selectedRow?: T;
   setSelectedRow: (row: T) => void;
   onOpenNewsletter: (row: T) => void;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   hasUnsubscribeAccess: boolean;
+  // biome-ignore lint/suspicious/noExplicitAny: simplest
   mutate: () => Promise<any>;
   emailAccountId: string;
   userEmail: string;
diff --git a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/types.ts b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/types.ts
index bce2389ac5..94dc1f8f61 100644
--- a/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/types.ts
+++ b/apps/web/app/(app)/[emailAccountId]/bulk-unsubscribe/types.ts
@@ -1,6 +1,7 @@
 import type { NewsletterStatsResponse } from "@/app/api/user/stats/newsletters/route";
 import type { NewsletterStatus } from "@prisma/client";
 import type { EmailLabel } from "@/providers/EmailProvider";
+import type { UserResponse } from "@/app/api/user/me/route";
 
 export type Row = {
   name: string;
@@ -21,12 +22,13 @@ export interface RowProps {
 
   onOpenNewsletter: (row: Newsletter) => void;
   labels: EmailLabel[];
+  // biome-ignore lint/suspicious/noExplicitAny: simplest
   mutate: () => Promise<any>;
   selected: boolean;
   onSelectRow: () => void;
   onDoubleClick: () => void;
   hasUnsubscribeAccess: boolean;
-  refetchPremium: () => Promise<any>;
+  refetchPremium: () => Promise<UserResponse | null | undefined>;
   openPremiumModal: () => void;
   checked: boolean;
   onToggleSelect: (id: string) => void;
diff --git a/apps/web/scripts/addUsersToResend.ts b/apps/web/scripts/addUsersToResend.ts
index 6d9721f299..1bf2353841 100644
--- a/apps/web/scripts/addUsersToResend.ts
+++ b/apps/web/scripts/addUsersToResend.ts
@@ -12,7 +12,8 @@ async function main() {
     try {
       if (user.email) {
         console.log("Adding user", user.email);
-        const { error } = await createContact({ email: user.email });
+        const result = await createContact({ email: user.email });
+        const error = result && "error" in result ? result.error : undefined;
         if (error) console.error(error);
       }
     } catch (error) {
diff --git a/apps/web/utils/email/microsoft.ts b/apps/web/utils/email/microsoft.ts
index cdf5e72a7c..9e9971503c 100644
--- a/apps/web/utils/email/microsoft.ts
+++ b/apps/web/utils/email/microsoft.ts
@@ -1,3 +1,4 @@
+import type { Message } from "@microsoft/microsoft-graph-types";
 import type { OutlookClient } from "@/utils/outlook/client";
 import type { ParsedMessage } from "@/utils/types";
 import {
@@ -294,10 +295,10 @@ export class OutlookProvider implements EmailProvider {
           logger,
         }),
       ]);
-      return { draftId: result.id };
+      return { draftId: result.id || "" };
     } else {
       const result = await draftEmail(this.client, email, args);
-      return { draftId: result.id };
+      return { draftId: result.id || "" };
     }
   }
 
@@ -402,8 +403,8 @@ export class OutlookProvider implements EmailProvider {
     });
 
     return {
-      id: label.id,
-      name: label.displayName || label.id,
+      id: label.id || "",
+      name: label.displayName || label.id || "",
       type: "user",
     };
   }
@@ -414,8 +415,8 @@ export class OutlookProvider implements EmailProvider {
       key,
     });
     return {
-      id: label.id,
-      name: label.displayName || label.id,
+      id: label.id || "",
+      name: label.displayName || label.id || "",
       type: "user",
     };
   }
@@ -435,27 +436,21 @@ export class OutlookProvider implements EmailProvider {
     try {
       const response = await getFiltersList({ client: this.client });
 
-      const mappedFilters = (response.value || []).map(
-        (filter: {
-          id: string;
-          conditions: { senderContains: string[] };
-          actions: { applyCategories: string[]; moveToFolder: string };
-        }) => {
-          const mappedFilter = {
-            id: filter.id || "",
-            criteria: {
-              from: filter.conditions?.senderContains?.[0] || undefined,
-            },
-            action: {
-              addLabelIds: filter.actions?.applyCategories || undefined,
-              removeLabelIds: filter.actions?.moveToFolder
-                ? ["INBOX"]
-                : undefined,
-            },
-          };
-          return mappedFilter;
-        },
-      );
+      const mappedFilters = (response.value || []).map((filter) => {
+        const mappedFilter = {
+          id: filter.id || "",
+          criteria: {
+            from: filter.conditions?.senderContains?.[0] || undefined,
+          },
+          action: {
+            addLabelIds: filter.actions?.assignCategories || undefined,
+            removeLabelIds: filter.actions?.moveToFolder
+              ? ["INBOX"]
+              : undefined,
+          },
+        };
+        return mappedFilter;
+      });
 
       return mappedFilters;
     } catch (error) {
@@ -468,14 +463,11 @@ export class OutlookProvider implements EmailProvider {
     from: string;
     addLabelIds?: string[];
     removeLabelIds?: string[];
-  }): Promise<any> {
+  }) {
     return createFilter({ client: this.client, ...options });
   }
 
-  async createAutoArchiveFilter(options: {
-    from: string;
-    labelName?: string;
-  }): Promise<any> {
+  async createAutoArchiveFilter(options: { from: string; labelName?: string }) {
     return createAutoArchiveFilter({
       client: this.client,
       from: options.from,
@@ -483,7 +475,7 @@ export class OutlookProvider implements EmailProvider {
     });
   }
 
-  async deleteFilter(id: string): Promise<any> {
+  async deleteFilter(id: string) {
     return deleteFilter({ client: this.client, id });
   }
 
@@ -810,7 +802,7 @@ export class OutlookProvider implements EmailProvider {
     messageId: string;
   }): Promise<boolean> {
     try {
-      const response = await this.client
+      const response: { value: Message[] } = await this.client
         .getClient()
         .api("/me/messages")
         .filter(
@@ -823,7 +815,7 @@ export class OutlookProvider implements EmailProvider {
       // Check if there are any messages from this sender before the current date
       // and exclude the current message
       const hasPreviousEmail = response.value.some(
-        (message: { id: string }) => message.id !== options.messageId,
+        (message) => message.id !== options.messageId,
       );
 
       return hasPreviousEmail;
diff --git a/apps/web/utils/outlook/attachment.ts b/apps/web/utils/outlook/attachment.ts
index 6728f9a4cd..4021231d4d 100644
--- a/apps/web/utils/outlook/attachment.ts
+++ b/apps/web/utils/outlook/attachment.ts
@@ -1,11 +1,12 @@
 import type { OutlookClient } from "@/utils/outlook/client";
+import type { FileAttachment } from "@microsoft/microsoft-graph-types";
 
 export async function getOutlookAttachment(
   client: OutlookClient,
   messageId: string,
   attachmentId: string,
 ) {
-  const attachment = await client
+  const attachment: FileAttachment = await client
     .getClient()
     .api(`/me/messages/${messageId}/attachments/${attachmentId}`)
     .get();
diff --git a/apps/web/utils/outlook/draft.ts b/apps/web/utils/outlook/draft.ts
index f0b7ed3c31..0a05ba9875 100644
--- a/apps/web/utils/outlook/draft.ts
+++ b/apps/web/utils/outlook/draft.ts
@@ -1,3 +1,4 @@
+import type { Message } from "@microsoft/microsoft-graph-types";
 import type { OutlookClient } from "@/utils/outlook/client";
 import { createScopedLogger } from "@/utils/logger";
 import { convertMessage } from "@/utils/outlook/message";
@@ -6,7 +7,7 @@ const logger = createScopedLogger("outlook/draft");
 
 export async function getDraft(draftId: string, client: OutlookClient) {
   try {
-    const response = await client
+    const response: Message = await client
       .getClient()
       .api(`/me/messages/${draftId}`)
       .get();
@@ -22,13 +23,7 @@ export async function getDraft(draftId: string, client: OutlookClient) {
 export async function deleteDraft(client: OutlookClient, draftId: string) {
   try {
     logger.info("Deleting draft", { draftId });
-    const response = await client
-      .getClient()
-      .api(`/me/messages/${draftId}`)
-      .delete();
-    if (response.status !== 204) {
-      logger.error("Failed to delete draft", { draftId, response });
-    }
+    await client.getClient().api(`/me/messages/${draftId}`).delete();
     logger.info("Successfully deleted draft", { draftId });
   } catch (error) {
     if (error instanceof Error && "code" in error && error.code === 404) {
diff --git a/apps/web/utils/outlook/filter.ts b/apps/web/utils/outlook/filter.ts
index 339a294774..2aff067ae5 100644
--- a/apps/web/utils/outlook/filter.ts
+++ b/apps/web/utils/outlook/filter.ts
@@ -1,5 +1,8 @@
 import type { OutlookClient } from "@/utils/outlook/client";
-import type { MessageRule } from "@microsoft/microsoft-graph-types";
+import type {
+  MessageRule,
+  OutlookCategory,
+} from "@microsoft/microsoft-graph-types";
 import { createScopedLogger } from "@/utils/logger";
 
 const logger = createScopedLogger("outlook/filter");
@@ -32,7 +35,7 @@ export async function createFilter(options: {
       },
     };
 
-    const response = await client
+    const response: MessageRule = await client
       .getClient()
       .api("/me/mailFolders/inbox/messageRules")
       .post(rule);
@@ -72,7 +75,7 @@ export async function createAutoArchiveFilter({
       },
     };
 
-    const response = await client
+    const response: MessageRule = await client
       .getClient()
       .api("/me/mailFolders/inbox/messageRules")
       .post(rule);
@@ -94,12 +97,12 @@ export async function deleteFilter(options: {
   const { client, id } = options;
 
   try {
-    const response = await client
+    await client
       .getClient()
       .api(`/me/mailFolders/inbox/messageRules/${id}`)
       .delete();
 
-    return { status: 204, data: response };
+    return { status: 204 };
   } catch (error) {
     logger.error("Error deleting Outlook filter", { id, error });
     throw error;
@@ -108,7 +111,7 @@ export async function deleteFilter(options: {
 
 export async function getFiltersList(options: { client: OutlookClient }) {
   try {
-    const response = await options.client
+    const response: { value: MessageRule[] } = await options.client
       .getClient()
       .api("/me/mailFolders/inbox/messageRules")
       .get();
@@ -126,6 +129,7 @@ export async function getFiltersList(options: { client: OutlookClient }) {
 
 // Helper function to check if a filter already exists
 function isFilterExistsError(error: unknown) {
+  // biome-ignore lint/suspicious/noExplicitAny: simplest
   const errorMessage = (error as any)?.message || "";
   return (
     errorMessage.includes("already exists") ||
@@ -147,13 +151,13 @@ export async function createCategoryFilter({
 }) {
   try {
     // First, ensure the category exists
-    const categories = await client
+    const categories: { value: OutlookCategory[] } = await client
       .getClient()
       .api("/me/outlook/masterCategories")
       .get();
 
     let category = categories.value.find(
-      (cat: { displayName: string }) => cat.displayName === categoryName,
+      (cat) => cat.displayName === categoryName,
     );
 
     if (!category) {
@@ -174,7 +178,7 @@ export async function createCategoryFilter({
     logger.info("Category created for filter", {
       from,
       categoryName,
-      categoryId: category.id,
+      categoryId: category?.id,
     });
 
     return {
@@ -218,7 +222,7 @@ export async function updateFilter({
       },
     };
 
-    const response = await client
+    const response: MessageRule = await client
       .getClient()
       .api(`/me/mailFolders/inbox/messageRules/${id}`)
       .patch(rule);
diff --git a/apps/web/utils/outlook/folders.ts b/apps/web/utils/outlook/folders.ts
index d6e7e81f80..d551a44758 100644
--- a/apps/web/utils/outlook/folders.ts
+++ b/apps/web/utils/outlook/folders.ts
@@ -1,3 +1,4 @@
+import type { MailFolder } from "@microsoft/microsoft-graph-types";
 import type { OutlookClient } from "./client";
 import { createScopedLogger } from "@/utils/logger";
 
@@ -6,17 +7,27 @@ const logger = createScopedLogger("outlook/folders");
 // Should not use a common separator like "/|\>" as it may be used in the folder name.
 // Using U+2999 as it is unlikely to appear in normal text
 export const FOLDER_SEPARATOR = " ⦙ ";
+
 export type OutlookFolder = {
-  id: string;
-  displayName: string;
-  childFolders?: OutlookFolder[];
+  id: NonNullable<MailFolder["id"]>;
+  displayName: NonNullable<MailFolder["displayName"]>;
+  childFolders: OutlookFolder[];
 };
 
+function convertMailFolderToOutlookFolder(folder: MailFolder): OutlookFolder {
+  return {
+    id: folder.id ?? "",
+    displayName: folder.displayName ?? "",
+    childFolders:
+      folder.childFolders?.map(convertMailFolderToOutlookFolder) ?? [],
+  };
+}
+
 export async function getOutlookRootFolders(
   client: OutlookClient,
 ): Promise<OutlookFolder[]> {
   const fields = "id,displayName";
-  const response = await client
+  const response: { value: MailFolder[] } = await client
     .getClient()
     .api("/me/mailFolders")
     .select(fields)
@@ -25,7 +36,7 @@ export async function getOutlookRootFolders(
     )
     .get();
 
-  return response.value;
+  return response.value.map(convertMailFolderToOutlookFolder);
 }
 
 export async function getOutlookChildFolders(
@@ -33,7 +44,7 @@ export async function getOutlookChildFolders(
   folderId: string,
 ): Promise<OutlookFolder[]> {
   const fields = "id,displayName";
-  const response = await client
+  const response: { value: MailFolder[] } = await client
     .getClient()
     .api(`/me/mailFolders/${folderId}/childFolders`)
     .select(fields)
@@ -42,7 +53,7 @@ export async function getOutlookChildFolders(
     )
     .get();
 
-  return response.value;
+  return response.value.map(convertMailFolderToOutlookFolder);
 }
 
 export async function getOutlookFolderTree(
@@ -57,7 +68,7 @@ export async function getOutlookFolderTree(
 
   const remainingLevels = expandLevels - 2;
   for (let currentLevel = 0; currentLevel < remainingLevels; currentLevel++) {
-    const folderQueue: OutlookFolder[] = [...folders];
+    const folderQueue = [...folders];
 
     while (folderQueue.length > 0) {
       const folder = folderQueue.shift()!;
@@ -72,7 +83,9 @@ export async function getOutlookFolderTree(
         }
       }
       if (folder.childFolders) {
-        folderQueue.push(...folder.childFolders);
+        folderQueue.push(
+          ...folder.childFolders.map(convertMailFolderToOutlookFolder),
+        );
       }
     }
   }
diff --git a/apps/web/utils/outlook/label.ts b/apps/web/utils/outlook/label.ts
index 292793141d..b10cb29881 100644
--- a/apps/web/utils/outlook/label.ts
+++ b/apps/web/utils/outlook/label.ts
@@ -4,16 +4,13 @@ import { publishArchive, type TinybirdEmailAction } from "@inboxzero/tinybird";
 import { WELL_KNOWN_FOLDERS } from "./message";
 
 import { inboxZeroLabels, type InboxZeroLabel } from "@/utils/label";
+import type {
+  OutlookCategory,
+  Message,
+} from "@microsoft/microsoft-graph-types";
 
 const logger = createScopedLogger("outlook/label");
 
-// Define our own Category type since Microsoft Graph types don't export it
-interface OutlookCategory {
-  id: string;
-  displayName?: string;
-  color?: string;
-}
-
 // Outlook doesn't have system labels like Gmail, but we map common categories
 // Using same format as Gmail for consistency
 export const OutlookLabel = {
@@ -57,11 +54,11 @@ export const OUTLOOK_COLOR_MAP = {
 } as const;
 
 export async function getLabels(client: OutlookClient) {
-  const response = await client
+  const response: { value: OutlookCategory[] } = await client
     .getClient()
     .api("/me/outlook/masterCategories")
     .get();
-  return (response.value as OutlookCategory[]).map((label) => ({
+  return response.value.map((label) => ({
     ...label,
     name: label.displayName || label.id,
   }));
@@ -72,11 +69,11 @@ export async function getLabelById(options: {
   id: string;
 }) {
   const { client, id } = options;
-  const response = await client
+  const response: OutlookCategory = await client
     .getClient()
     .api(`/me/outlook/masterCategories/${id}`)
     .get();
-  return response as OutlookCategory;
+  return response;
 }
 
 export async function createLabel({
@@ -95,14 +92,14 @@ export async function createLabel({
         ? color
         : OUTLOOK_COLORS[Math.floor(Math.random() * OUTLOOK_COLORS.length)];
 
-    const response = await client
+    const response: OutlookCategory = await client
       .getClient()
       .api("/me/outlook/masterCategories")
       .post({
         displayName: name,
         color: outlookColor,
       });
-    return response as OutlookCategory;
+    return response;
   } catch (error) {
     const errorMessage =
       error instanceof Error ? error.message : "Unknown error";
@@ -217,15 +214,15 @@ export async function labelThread({
   // In Outlook, we need to update each message in the thread
   // Escape single quotes in threadId for the filter
   const escapedThreadId = threadId.replace(/'/g, "''");
-  const messages = await client
+  const messages: { value: Message[] } = await client
     .getClient()
     .api("/me/messages")
     .filter(`conversationId eq '${escapedThreadId}'`)
     .get();
 
   await Promise.all(
-    messages.value.map((message: { id: string }) =>
-      labelMessage({ client, messageId: message.id, categories }),
+    messages.value.map((message) =>
+      labelMessage({ client, messageId: message.id!, categories }),
     ),
   );
 }
diff --git a/apps/web/utils/outlook/mail.ts b/apps/web/utils/outlook/mail.ts
index 0c4e2c4a86..25a8385ebe 100644
--- a/apps/web/utils/outlook/mail.ts
+++ b/apps/web/utils/outlook/mail.ts
@@ -1,3 +1,4 @@
+import type { Message } from "@microsoft/microsoft-graph-types";
 import type { OutlookClient } from "@/utils/outlook/client";
 import type { Attachment } from "nodemailer/lib/mailer";
 import type { SendEmailBody } from "@/utils/gmail/mail";
@@ -46,7 +47,10 @@ export async function sendEmailWithHtml(
     message.conversationId = body.replyToEmail.threadId;
   }
 
-  const result = await client.getClient().api("/me/messages").post(message);
+  const result: Message = await client
+    .getClient()
+    .api("/me/messages")
+    .post(message);
   return result;
 }
 
@@ -105,7 +109,7 @@ export async function forwardEmail(
   if (!options.to.trim()) throw new Error("Recipient address is required");
 
   // Get the original message
-  const originalMessage = await client
+  const originalMessage: Message = await client
     .getClient()
     .api(`/me/messages/${options.messageId}`)
     .get();
@@ -202,7 +206,10 @@ export async function draftEmail(
     isDraft: true,
   };
 
-  const result = await client.getClient().api("/me/messages").post(draft);
+  const result: Message = await client
+    .getClient()
+    .api("/me/messages")
+    .post(draft);
   return result;
 }
 
diff --git a/apps/web/utils/outlook/message.ts b/apps/web/utils/outlook/message.ts
index ba55943c9e..dfe97b7cd7 100644
--- a/apps/web/utils/outlook/message.ts
+++ b/apps/web/utils/outlook/message.ts
@@ -181,7 +181,8 @@ export async function queryBatchMessages(
         request = request.skipToken(pageToken);
       }
 
-      const response = await request.get();
+      const response: { value: Message[]; "@odata.nextLink"?: string } =
+        await request.get();
       const messages = await convertMessages(response.value, folderIds);
 
       // For filter, get next page token from @odata.nextLink
@@ -204,10 +205,11 @@ export async function queryBatchMessages(
         request = request.skipToken(pageToken);
       }
 
-      const response = await request.get();
+      const response: { value: Message[]; "@odata.nextLink"?: string } =
+        await request.get();
       // Filter messages to only include inbox and archive folders
       const filteredMessages = response.value.filter(
-        (message: Message) =>
+        (message) =>
           message.parentFolderId === inboxFolderId ||
           message.parentFolderId === archiveFolderId,
       );
@@ -242,7 +244,7 @@ export async function queryBatchMessages(
       .skip(pageToken ? Number.parseInt(pageToken, 10) : 0)
       .orderby("receivedDateTime DESC");
 
-    const response = await request.get();
+    const response: { value: Message[] } = await request.get();
     const messages = await convertMessages(response.value, folderIds);
 
     // For non-search, calculate next page token based on message count
@@ -316,7 +318,8 @@ export async function getMessages(
     );
   }
 
-  const response = await request.get();
+  const response: { value: Message[]; "@odata.nextLink"?: string } =
+    await request.get();
 
   // Get folder IDs to properly map labels
   const folderIds = await getFolderIds(client);
diff --git a/apps/web/utils/outlook/thread.ts b/apps/web/utils/outlook/thread.ts
index 1ad6222b50..d1b2e8c406 100644
--- a/apps/web/utils/outlook/thread.ts
+++ b/apps/web/utils/outlook/thread.ts
@@ -7,7 +7,7 @@ export async function getThread(
   threadId: string,
   client: OutlookClient,
 ): Promise<Message[]> {
-  const messages = await client
+  const messages: { value: Message[] } = await client
     .getClient()
     .api("/me/messages")
     .filter(`conversationId eq '${threadId}'`)
@@ -25,13 +25,19 @@ export async function getThreads(
   nextPageToken?: string | null;
   threads: { id: string; snippet: string }[];
 }> {
-  const response = await client
-    .getClient()
-    .api("/me/messages")
-    .filter(query ? `contains(subject, '${escapeODataString(query)}')` : "")
-    .top(maxResults)
-    .select("id,conversationId,subject,bodyPreview")
-    .get();
+  let request = client.getClient().api("/me/messages");
+
+  if (query) {
+    request = request.filter(
+      `contains(subject, '${escapeODataString(query)}')`,
+    );
+  }
+
+  const response: { value: Message[]; "@odata.nextLink"?: string } =
+    await request
+      .top(maxResults)
+      .select("id,conversationId,subject,bodyPreview")
+      .get();
 
   // Group messages by conversationId to create thread-like structure
   const threadMap = new Map<string, { id: string; snippet: string }>();
@@ -73,7 +79,8 @@ export async function getThreadsWithNextPageToken({
     );
   }
 
-  const response = await request.get();
+  const response: { value: Message[]; "@odata.nextLink"?: string } =
+    await request.get();
 
   // Group messages by conversationId to create thread-like structure
   const threadMap = new Map<string, { id: string; snippet: string }>();
@@ -97,7 +104,7 @@ export async function getThreadsFromSender(
   sender: string,
   limit: number,
 ): Promise<Array<{ id: string; snippet: string }>> {
-  const response = await client
+  const response: { value: Message[] } = await client
     .getClient()
     .api("/me/messages")
     .filter(`from/emailAddress/address eq '${escapeODataString(sender)}'`)
@@ -124,7 +131,7 @@ export async function getThreadsFromSenderWithSubject(
   sender: string,
   limit: number,
 ): Promise<Array<{ id: string; snippet: string; subject: string }>> {
-  const response = await client
+  const response: { value: Message[] } = await client
     .getClient()
     .api("/me/messages")
     .filter(`from/emailAddress/address eq '${escapeODataString(sender)}'`)
@@ -154,7 +161,7 @@ export async function getThreadMessages(
   threadId: string,
   client: OutlookClient,
 ): Promise<ParsedMessage[]> {
-  const messages = await getThread(threadId, client);
+  const messages: Message[] = await getThread(threadId, client);
 
   return messages.map((msg) => ({
     id: msg.id || "",
diff --git a/biome.json b/biome.json
index 451eec35db..ab6d71401d 100644
--- a/biome.json
+++ b/biome.json
@@ -24,7 +24,7 @@
       },
       "suspicious": {
         "noConsole": "warn",
-        "noExplicitAny": "off",
+        "noExplicitAny": "warn",
         "noArrayIndexKey": "off",
         "noEmptyBlockStatements": "off",
         "useAwait": "off",
diff --git a/packages/resend/src/contacts.ts b/packages/resend/src/contacts.ts
index 25e759a608..d85bc8d6d2 100644
--- a/packages/resend/src/contacts.ts
+++ b/packages/resend/src/contacts.ts
@@ -3,7 +3,7 @@ import { resend } from "./client";
 export async function createContact(options: {
   email: string;
   audienceId?: string;
-}): Promise<any> {
+}) {
   if (!resend) {
     console.warn("Resend not configured");
     return;
@@ -16,7 +16,7 @@ export async function createContact(options: {
 export async function deleteContact(options: {
   email: string;
   audienceId?: string;
-}): Promise<any> {
+}) {
   if (!resend) {
     console.warn("Resend not configured");
     return;
diff --git a/version.txt b/version.txt
index c9c156a3a8..bbd0034cee 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-v2.7.3
+v2.7.4