diff --git a/apps/desktop/package.json b/apps/desktop/package.json
index a72fe284e2e..a1894df9deb 100644
--- a/apps/desktop/package.json
+++ b/apps/desktop/package.json
@@ -57,6 +57,7 @@
 		"@codemirror/lang-yaml": "^6.1.2",
 		"@codemirror/language": "^6.12.2",
 		"@codemirror/legacy-modes": "^6.5.2",
+		"@codemirror/merge": "^6.12.1",
 		"@codemirror/search": "^6.6.0",
 		"@codemirror/state": "^6.5.4",
 		"@codemirror/theme-one-dark": "^6.1.3",
diff --git a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/CodeMirrorDiffViewer.tsx b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/CodeMirrorDiffViewer.tsx
new file mode 100644
index 00000000000..177dae7bfa5
--- /dev/null
+++ b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/CodeMirrorDiffViewer.tsx
@@ -0,0 +1,132 @@
+import { defaultKeymap, indentWithTab } from "@codemirror/commands";
+import { MergeView } from "@codemirror/merge";
+import { highlightSelectionMatches, searchKeymap } from "@codemirror/search";
+import { Compartment, EditorState } from "@codemirror/state";
+import {
+	drawSelection,
+	EditorView,
+	highlightSpecialChars,
+	keymap,
+	lineNumbers,
+} from "@codemirror/view";
+import { useEffect, useRef } from "react";
+import { electronTrpc } from "renderer/lib/electron-trpc";
+import { createCodeMirrorTheme } from "renderer/screens/main/components/WorkspaceView/components/CodeEditor/createCodeMirrorTheme";
+import { loadLanguageSupport } from "renderer/screens/main/components/WorkspaceView/components/CodeEditor/loadLanguageSupport";
+import { getCodeSyntaxHighlighting } from "renderer/screens/main/components/WorkspaceView/utils/code-theme";
+import { useResolvedTheme } from "renderer/stores/theme";
+import type { DiffViewMode } from "shared/changes-types";
+
+interface CodeMirrorDiffViewerProps {
+	original: string;
+	modified: string;
+	language: string;
+	viewMode: DiffViewMode;
+}
+
+export function CodeMirrorDiffViewer({
+	original,
+	modified,
+	language,
+	viewMode,
+}: CodeMirrorDiffViewerProps) {
+	const containerRef = useRef<HTMLDivElement>(null);
+	const mergeViewRef = useRef<MergeView | null>(null);
+	const langCompartmentA = useRef(new Compartment()).current;
+	const langCompartmentB = useRef(new Compartment()).current;
+	const themeCompartmentA = useRef(new Compartment()).current;
+	const themeCompartmentB = useRef(new Compartment()).current;
+	const activeTheme = useResolvedTheme();
+	const { data: fontSettings } = electronTrpc.settings.getFontSettings.useQuery(
+		undefined,
+		{ staleTime: 30_000 },
+	);
+	const editorFontFamily = fontSettings?.editorFontFamily ?? undefined;
+	const editorFontSize = fontSettings?.editorFontSize ?? undefined;
+
+	// biome-ignore lint/correctness/useExhaustiveDependencies: MergeView is created once and destroyed on unmount
+	useEffect(() => {
+		if (!containerRef.current) return;
+
+		const baseExtensions = [
+			lineNumbers(),
+			highlightSpecialChars(),
+			drawSelection(),
+			highlightSelectionMatches(),
+			EditorState.readOnly.of(true),
+			EditorView.editable.of(false),
+			EditorView.lineWrapping,
+			keymap.of([indentWithTab, ...defaultKeymap, ...searchKeymap]),
+		];
+
+		const themeExts = [
+			getCodeSyntaxHighlighting(activeTheme),
+			createCodeMirrorTheme(
+				activeTheme,
+				{ fontFamily: editorFontFamily, fontSize: editorFontSize },
+				true,
+			),
+		];
+
+		const mergeView = new MergeView({
+			parent: containerRef.current,
+			collapseUnchanged: { margin: 3, minSize: 4 },
+			diffConfig: { scanLimit: 50000, timeout: 5000 },
+			a: {
+				doc: original,
+				extensions: [
+					...baseExtensions,
+					themeCompartmentA.of(themeExts),
+					langCompartmentA.of([]),
+				],
+			},
+			b: {
+				doc: modified,
+				extensions: [
+					...baseExtensions,
+					themeCompartmentB.of(themeExts),
+					langCompartmentB.of([]),
+				],
+			},
+		});
+
+		mergeViewRef.current = mergeView;
+
+		void loadLanguageSupport(language).then((ext) => {
+			if (!ext || !mergeViewRef.current) return;
+			const mv = mergeViewRef.current;
+			mv.a.dispatch({ effects: langCompartmentA.reconfigure(ext) });
+			mv.b.dispatch({ effects: langCompartmentB.reconfigure(ext) });
+		});
+
+		return () => {
+			mergeView.destroy();
+			mergeViewRef.current = null;
+		};
+	}, [original, modified, language, viewMode]);
+
+	useEffect(() => {
+		const mv = mergeViewRef.current;
+		if (!mv) return;
+
+		const themeExts = [
+			getCodeSyntaxHighlighting(activeTheme),
+			createCodeMirrorTheme(
+				activeTheme,
+				{ fontFamily: editorFontFamily, fontSize: editorFontSize },
+				true,
+			),
+		];
+
+		mv.a.dispatch({ effects: themeCompartmentA.reconfigure(themeExts) });
+		mv.b.dispatch({ effects: themeCompartmentB.reconfigure(themeExts) });
+	}, [
+		activeTheme,
+		editorFontFamily,
+		editorFontSize,
+		themeCompartmentA,
+		themeCompartmentB,
+	]);
+
+	return <div ref={containerRef} className="h-full w-full overflow-auto" />;
+}
diff --git a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/index.ts b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/index.ts
new file mode 100644
index 00000000000..13fcbde4860
--- /dev/null
+++ b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/CodeMirrorDiffViewer/index.ts
@@ -0,0 +1 @@
+export { CodeMirrorDiffViewer } from "./CodeMirrorDiffViewer";
diff --git a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/FileViewerContent/FileViewerContent.tsx b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/FileViewerContent/FileViewerContent.tsx
index 0148172700f..61c7e13eedd 100644
--- a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/FileViewerContent/FileViewerContent.tsx
+++ b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/TabView/FileViewerPane/components/FileViewerContent/FileViewerContent.tsx
@@ -18,6 +18,7 @@ import { detectLanguage } from "shared/detect-language";
 import { isImageFile, isSpreadsheetFile } from "shared/file-types";
 import type { FileViewerMode } from "shared/tabs-types";
 import { useScrollToFirstDiffChange } from "../../hooks/useScrollToFirstDiffChange";
+import { CodeMirrorDiffViewer } from "../CodeMirrorDiffViewer";
 import { DiffScrollbarDecorations } from "../DiffScrollbarDecorations";
 import { DiffViewerContextMenu } from "../DiffViewerContextMenu";
 import { FileEditorContextMenu } from "../FileEditorContextMenu";
@@ -319,6 +320,11 @@ export function FileViewerContent({
 			);
 		}
 
+		const totalLines =
+			diffData.original.split("\n").length +
+			diffData.modified.split("\n").length;
+		const useLargeDiffViewer = totalLines > 2000;
+
 		return (
 			<DiffViewerContextMenu
 				containerRef={diffContainerRef}
@@ -347,18 +353,20 @@ export function FileViewerContent({
 				}}
 			>
 				<div className="relative h-full">
-					<MarkdownSearch
-						isOpen={diffSearch.isSearchOpen}
-						query={diffSearch.query}
-						caseSensitive={diffSearch.caseSensitive}
-						matchCount={diffSearch.matchCount}
-						activeMatchIndex={diffSearch.activeMatchIndex}
-						onQueryChange={diffSearch.setQuery}
-						onCaseSensitiveChange={diffSearch.setCaseSensitive}
-						onFindNext={diffSearch.findNext}
-						onFindPrevious={diffSearch.findPrevious}
-						onClose={diffSearch.closeSearch}
-					/>
+					{!useLargeDiffViewer && (
+						<MarkdownSearch
+							isOpen={diffSearch.isSearchOpen}
+							query={diffSearch.query}
+							caseSensitive={diffSearch.caseSensitive}
+							matchCount={diffSearch.matchCount}
+							activeMatchIndex={diffSearch.activeMatchIndex}
+							onQueryChange={diffSearch.setQuery}
+							onCaseSensitiveChange={diffSearch.setCaseSensitive}
+							onFindNext={diffSearch.findNext}
+							onFindPrevious={diffSearch.findPrevious}
+							onClose={diffSearch.closeSearch}
+						/>
+					)}
 					<div
 						ref={diffContainerRef}
 						className="h-full min-h-0 overflow-auto bg-background select-text"
@@ -368,6 +376,7 @@ export function FileViewerContent({
 							}
 						}}
 						onContextMenuCapture={(event) => {
+							if (useLargeDiffViewer) return;
 							const location = getDiffLocationFromEvent(event.nativeEvent);
 							if (!location) {
 								return;
@@ -386,16 +395,27 @@ export function FileViewerContent({
 							};
 						}}
 					>
-						<LightDiffViewer
-							key={filePath}
-							contents={diffData}
-							viewMode={diffViewMode}
-							hideUnchangedRegions={hideUnchangedRegions}
-							filePath={filePath}
-							className="min-h-full"
-						/>
+						{useLargeDiffViewer ? (
+							<CodeMirrorDiffViewer
+								original={diffData.original}
+								modified={diffData.modified}
+								language={diffData.language}
+								viewMode={diffViewMode}
+							/>
+						) : (
+							<LightDiffViewer
+								key={filePath}
+								contents={diffData}
+								viewMode={diffViewMode}
+								hideUnchangedRegions={hideUnchangedRegions}
+								filePath={filePath}
+								className="min-h-full"
+							/>
+						)}
 					</div>
-					<DiffScrollbarDecorations scrollContainerRef={diffContainerRef} />
+					{!useLargeDiffViewer && (
+						<DiffScrollbarDecorations scrollContainerRef={diffContainerRef} />
+					)}
 				</div>
 			</DiffViewerContextMenu>
 		);
diff --git a/bun.lock b/bun.lock
index aefab368d8d..25e3c5bef40 100644
--- a/bun.lock
+++ b/bun.lock
@@ -134,6 +134,7 @@
         "@codemirror/lang-yaml": "^6.1.2",
         "@codemirror/language": "^6.12.2",
         "@codemirror/legacy-modes": "^6.5.2",
+        "@codemirror/merge": "^6.12.1",
         "@codemirror/search": "^6.6.0",
         "@codemirror/state": "^6.5.4",
         "@codemirror/theme-one-dark": "^6.1.3",
@@ -1295,6 +1296,8 @@
 
     "@codemirror/lint": ["@codemirror/lint@6.9.5", "", { "dependencies": { "@codemirror/state": "^6.0.0", "@codemirror/view": "^6.35.0", "crelt": "^1.0.5" } }, "sha512-GElsbU9G7QT9xXhpUg1zWGmftA/7jamh+7+ydKRuT0ORpWS3wOSP0yT1FOlIZa7mIJjpVPipErsyvVqB9cfTFA=="],
 
+    "@codemirror/merge": ["@codemirror/merge@6.12.1", "", { "dependencies": { "@codemirror/language": "^6.0.0", "@codemirror/state": "^6.0.0", "@codemirror/view": "^6.17.0", "@lezer/highlight": "^1.0.0", "style-mod": "^4.1.0" } }, "sha512-GA8hBq2T+IFM0sb5fk8CunTrqOulA3zurJmHtzcU15EMnL8aYpVINfJ5bkfd53M4ikwoew4Y1ydtSaAlk6+B1w=="],
+
     "@codemirror/search": ["@codemirror/search@6.6.0", "", { "dependencies": { "@codemirror/state": "^6.0.0", "@codemirror/view": "^6.37.0", "crelt": "^1.0.5" } }, "sha512-koFuNXcDvyyotWcgOnZGmY7LZqEOXZaaxD/j6n18TCLx2/9HieZJ5H6hs1g8FiRxBD0DNfs0nXn17g872RmYdw=="],
 
     "@codemirror/state": ["@codemirror/state@6.5.4", "", { "dependencies": { "@marijn/find-cluster-break": "^1.0.0" } }, "sha512-8y7xqG/hpB53l25CIoit9/ngxdfoG+fx+V3SHBrinnhOtLvKHRyAJJuHzkWrR4YXXLX8eXBsejgAAxHUOdW1yw=="],