diff --git a/surfsense_backend/app/routes/editor_routes.py b/surfsense_backend/app/routes/editor_routes.py
index 0f986e416..7abbdd31d 100644
--- a/surfsense_backend/app/routes/editor_routes.py
+++ b/surfsense_backend/app/routes/editor_routes.py
@@ -38,6 +38,8 @@ logger = logging.getLogger(__name__)
 
 router = APIRouter()
 
+EDITOR_PLATE_MAX_BYTES = 2 * 1024 * 1024
+
 
 @router.get("/search-spaces/{search_space_id}/documents/{document_id}/editor-content")
 async def get_editor_content(
@@ -84,6 +86,7 @@ async def get_editor_content(
 
     def _build_response(md: str) -> dict:
         size_bytes = len(md.encode("utf-8"))
+        viewer_mode = "monaco" if size_bytes > EDITOR_PLATE_MAX_BYTES else "plate"
         truncated = False
         output_md = md
         if max_length is not None and size_bytes > max_length:
@@ -97,6 +100,7 @@ async def get_editor_content(
             "content_size_bytes": size_bytes,
             "chunk_count": chunk_count,
             "truncated": truncated,
+            "viewer_mode": viewer_mode,
             "updated_at": document.updated_at.isoformat()
             if document.updated_at
             else None,
diff --git a/surfsense_web/components/editor-panel/editor-panel.tsx b/surfsense_web/components/editor-panel/editor-panel.tsx
index 945fbc529..2c0d316d9 100644
--- a/surfsense_web/components/editor-panel/editor-panel.tsx
+++ b/surfsense_web/components/editor-panel/editor-panel.tsx
@@ -51,10 +51,12 @@ interface EditorContent {
 	content_size_bytes?: number;
 	chunk_count?: number;
 	truncated?: boolean;
+	viewer_mode?: ViewerMode;
 }
 
 const EDITABLE_DOCUMENT_TYPES = new Set(["FILE", "NOTE"]);
 type EditorRenderMode = "rich_markdown" | "source_code";
+type ViewerMode = "plate" | "monaco";
 
 type AgentFilesystemMount = {
 	mount: string;
@@ -168,6 +170,9 @@ export function EditorPanelContent({
 	);
 
 	const isLargeDocument = (editorDoc?.content_size_bytes ?? 0) > LARGE_DOCUMENT_THRESHOLD;
+	const viewerMode: ViewerMode = isMemoryMode
+		? "plate"
+		: (editorDoc?.viewer_mode ?? (isLargeDocument ? "monaco" : "plate"));
 
 	useEffect(() => {
 		const controller = new AbortController();
@@ -432,12 +437,10 @@ export function EditorPanelContent({
 		? (isMemoryMode ||
 				editorRenderMode === "source_code" ||
 				EDITABLE_DOCUMENT_TYPES.has(editorDoc.document_type ?? "")) &&
-			!isLargeDocument
+			viewerMode === "plate"
 		: false;
-	// Render through PlateEditor for editable doc types (FILE/NOTE).
-	// Everything else (large docs, non-editable types) falls back to the
-	// lightweight `MarkdownViewer` — Plate is heavy on multi-MB docs and
-	// non-editable types don't benefit from its editing UX.
+	// Render through PlateEditor only when the backend says the rich editor is safe.
+	// Monaco mode is a raw markdown safety path for large documents.
 	const renderInPlateEditor = isEditableType;
 	const hasUnsavedChanges = editedMarkdown !== null;
 	const showDesktopHeader = !!onClose;
@@ -492,14 +495,14 @@ export function EditorPanelContent({
 		}
 	}, [documentId, editorDoc?.title, searchSpaceId]);
 
-	const largeDocAlert = isLargeDocument && !isLocalFileMode && editorDoc && (
-		<Alert className="mb-4">
+	const largeDocAlert = viewerMode === "monaco" && !isLocalFileMode && editorDoc && (
+		<Alert className="m-4 shrink-0">
 			<FileText className="size-4" />
 			<AlertDescription className="flex items-center justify-between gap-4">
 				<span>
 					This document is too large for the editor (
 					{Math.round((editorDoc.content_size_bytes ?? 0) / 1024 / 1024)}MB,{" "}
-					{editorDoc.chunk_count ?? 0} chunks). Showing a preview below.
+					{editorDoc.chunk_count ?? 0} chunks). Showing raw markdown below.
 				</span>
 				<Button
 					variant="outline"
@@ -753,12 +756,19 @@ export function EditorPanelContent({
 							}}
 						/>
 					</div>
-				) : isLargeDocument && !isLocalFileMode ? (
-					// Large doc — fast Streamdown preview + download CTA.
-					// Plate is heavy on multi-MB docs.
-					<div className="h-full overflow-y-auto px-5 py-4">
+				) : viewerMode === "monaco" && !isLocalFileMode ? (
+					// Large doc — raw markdown in Monaco. Rich renderers are intentionally skipped.
+					<div className="flex h-full min-h-0 flex-col">
 						{largeDocAlert}
-						<MarkdownViewer content={editorDoc.source_markdown} enableCitations />
+						<div className="min-h-0 flex-1 overflow-hidden">
+							<SourceCodeEditor
+								path={`${editorDoc.title || "document"}.md`}
+								language="markdown"
+								value={editorDoc.source_markdown}
+								readOnly
+								onChange={() => {}}
+							/>
+						</div>
 					</div>
 				) : renderInPlateEditor ? (
 					// Editable doc (FILE/NOTE) — Plate editing UX.
diff --git a/surfsense_web/components/layout/ui/tabs/DocumentTabContent.tsx b/surfsense_web/components/layout/ui/tabs/DocumentTabContent.tsx
index 34cf707b0..345347e9e 100644
--- a/surfsense_web/components/layout/ui/tabs/DocumentTabContent.tsx
+++ b/surfsense_web/components/layout/ui/tabs/DocumentTabContent.tsx
@@ -5,6 +5,7 @@ import { useRouter } from "next/navigation";
 import { useCallback, useEffect, useRef, useState } from "react";
 import { toast } from "sonner";
 import { PlateEditor } from "@/components/editor/plate-editor";
+import { SourceCodeEditor } from "@/components/editor/source-code-editor";
 import { MarkdownViewer } from "@/components/markdown-viewer";
 import { Alert, AlertDescription } from "@/components/ui/alert";
 import { Button } from "@/components/ui/button";
@@ -22,6 +23,7 @@ interface DocumentContent {
 	content_size_bytes?: number;
 	chunk_count?: number;
 	truncated?: boolean;
+	viewer_mode?: ViewerMode;
 }
 
 function DocumentSkeleton() {
@@ -51,6 +53,7 @@ interface DocumentTabContentProps {
 }
 
 const EDITABLE_DOCUMENT_TYPES = new Set(["FILE", "NOTE"]);
+type ViewerMode = "plate" | "monaco";
 
 export function DocumentTabContent({ documentId, searchSpaceId, title }: DocumentTabContentProps) {
 	const [doc, setDoc] = useState<DocumentContent | null>(null);
@@ -66,6 +69,7 @@ export function DocumentTabContent({ documentId, searchSpaceId, title }: Documen
 	const router = useRouter();
 
 	const isLargeDocument = (doc?.content_size_bytes ?? 0) > LARGE_DOCUMENT_THRESHOLD;
+	const viewerMode: ViewerMode = doc?.viewer_mode ?? (isLargeDocument ? "monaco" : "plate");
 
 	useEffect(() => {
 		const controller = new AbortController();
@@ -204,9 +208,9 @@ export function DocumentTabContent({ documentId, searchSpaceId, title }: Documen
 		);
 	}
 
-	const isEditable = EDITABLE_DOCUMENT_TYPES.has(doc.document_type ?? "") && !isLargeDocument;
+	const isEditable = viewerMode === "plate" && EDITABLE_DOCUMENT_TYPES.has(doc.document_type ?? "");
 
-	if (isEditing && !isLargeDocument) {
+	if (isEditing && viewerMode === "plate") {
 		return (
 			<div className="flex flex-col h-full overflow-hidden">
 				<div className="flex items-center justify-between px-6 py-3 border-b shrink-0">
@@ -265,64 +269,74 @@ export function DocumentTabContent({ documentId, searchSpaceId, title }: Documen
 					</Button>
 				)}
 			</div>
-			<div className="flex-1 overflow-auto">
-				<div className="max-w-4xl mx-auto px-6 py-6">
-					{isLargeDocument ? (
-						<>
-							<Alert className="mb-4">
-								<FileText className="size-4" />
-								<AlertDescription className="flex items-center justify-between gap-4">
-									<span>
-										This document is too large for the editor (
-										{Math.round((doc.content_size_bytes ?? 0) / 1024 / 1024)}MB,{" "}
-										{doc.chunk_count ?? 0} chunks). Showing a preview below.
+			<div className="flex-1 min-h-0 overflow-hidden">
+				{viewerMode === "monaco" ? (
+					<div className="flex h-full min-h-0 flex-col">
+						<Alert className="m-4 shrink-0">
+							<FileText className="size-4" />
+							<AlertDescription className="flex items-center justify-between gap-4">
+								<span>
+									This document is too large for the editor (
+									{Math.round((doc.content_size_bytes ?? 0) / 1024 / 1024)}MB,{" "}
+									{doc.chunk_count ?? 0} chunks). Showing raw markdown below.
+								</span>
+								<Button
+									variant="outline"
+									size="sm"
+									className="relative shrink-0"
+									disabled={downloading}
+									onClick={async () => {
+										setDownloading(true);
+										try {
+											const response = await authenticatedFetch(
+												`${BACKEND_URL}/api/v1/search-spaces/${searchSpaceId}/documents/${documentId}/download-markdown`,
+												{ method: "GET" }
+											);
+											if (!response.ok) throw new Error("Download failed");
+											const blob = await response.blob();
+											const url = URL.createObjectURL(blob);
+											const a = document.createElement("a");
+											a.href = url;
+											const disposition = response.headers.get("content-disposition");
+											const match = disposition?.match(/filename="(.+)"/);
+											a.download = match?.[1] ?? `${doc.title || "document"}.md`;
+											document.body.appendChild(a);
+											a.click();
+											a.remove();
+											URL.revokeObjectURL(url);
+											toast.success("Download started");
+										} catch {
+											toast.error("Failed to download document");
+										} finally {
+											setDownloading(false);
+										}
+									}}
+								>
+									<span className={`flex items-center gap-1.5 ${downloading ? "opacity-0" : ""}`}>
+										<Download className="size-3.5" />
+										Download .md
 									</span>
-									<Button
-										variant="outline"
-										size="sm"
-										className="relative shrink-0"
-										disabled={downloading}
-										onClick={async () => {
-											setDownloading(true);
-											try {
-												const response = await authenticatedFetch(
-													`${BACKEND_URL}/api/v1/search-spaces/${searchSpaceId}/documents/${documentId}/download-markdown`,
-													{ method: "GET" }
-												);
-												if (!response.ok) throw new Error("Download failed");
-												const blob = await response.blob();
-												const url = URL.createObjectURL(blob);
-												const a = document.createElement("a");
-												a.href = url;
-												const disposition = response.headers.get("content-disposition");
-												const match = disposition?.match(/filename="(.+)"/);
-												a.download = match?.[1] ?? `${doc.title || "document"}.md`;
-												document.body.appendChild(a);
-												a.click();
-												a.remove();
-												URL.revokeObjectURL(url);
-												toast.success("Download started");
-											} catch {
-												toast.error("Failed to download document");
-											} finally {
-												setDownloading(false);
-											}
-										}}
-									>
-										<span className={`flex items-center gap-1.5 ${downloading ? "opacity-0" : ""}`}>
-											<Download className="size-3.5" />
-											Download .md
-										</span>
-										{downloading && <Spinner size="sm" className="absolute" />}
-									</Button>
-								</AlertDescription>
-							</Alert>
+									{downloading && <Spinner size="sm" className="absolute" />}
+								</Button>
+							</AlertDescription>
+						</Alert>
+						<div className="min-h-0 flex-1 overflow-hidden">
+							<SourceCodeEditor
+								path={`${doc.title || "document"}.md`}
+								language="markdown"
+								value={doc.source_markdown}
+								readOnly
+								onChange={() => {}}
+							/>
+						</div>
+					</div>
+				) : (
+					<div className="h-full overflow-auto">
+						<div className="max-w-4xl mx-auto px-6 py-6">
 							<MarkdownViewer content={doc.source_markdown} enableCitations />
-						</>
-					) : (
-						<MarkdownViewer content={doc.source_markdown} enableCitations />
-					)}
-				</div>
+						</div>
+					</div>
+				)}
 			</div>
 		</div>
 	);
diff --git a/surfsense_web/tests/helpers/api/documents.ts b/surfsense_web/tests/helpers/api/documents.ts
index 92055602b..0d8cc8839 100644
--- a/surfsense_web/tests/helpers/api/documents.ts
+++ b/surfsense_web/tests/helpers/api/documents.ts
@@ -44,6 +44,7 @@ export type EditorContent = {
 	content_size_bytes: number;
 	chunk_count: number;
 	truncated: boolean;
+	viewer_mode?: "plate" | "monaco";
 };
 
 // Same endpoint the UI hits when a user opens a document in the dashboard.