diff --git a/crates/db/src/models/scratch.rs b/crates/db/src/models/scratch.rs
index 0a9d379d..8af527cb 100644
--- a/crates/db/src/models/scratch.rs
+++ b/crates/db/src/models/scratch.rs
@@ -25,6 +25,12 @@ pub struct DraftFollowUpData {
     pub variant: Option<String>,
 }
 
+/// Data for a preview URL override scratch
+#[derive(Debug, Clone, Serialize, Deserialize, TS)]
+pub struct PreviewUrlOverrideData {
+    pub url: String,
+}
+
 /// Data for a draft workspace scratch (new workspace creation)
 #[derive(Debug, Clone, Serialize, Deserialize, TS)]
 pub struct DraftWorkspaceData {
@@ -57,6 +63,7 @@ pub enum ScratchPayload {
     DraftTask(String),
     DraftFollowUp(DraftFollowUpData),
     DraftWorkspace(DraftWorkspaceData),
+    PreviewUrlOverride(PreviewUrlOverrideData),
 }
 
 impl ScratchPayload {
diff --git a/crates/server/src/bin/generate_types.rs b/crates/server/src/bin/generate_types.rs
index 8171fd9e..4d8350d4 100644
--- a/crates/server/src/bin/generate_types.rs
+++ b/crates/server/src/bin/generate_types.rs
@@ -39,6 +39,7 @@ fn generate_types_content() -> String {
         db::models::scratch::DraftFollowUpData::decl(),
         db::models::scratch::DraftWorkspaceData::decl(),
         db::models::scratch::DraftWorkspaceRepo::decl(),
+        db::models::scratch::PreviewUrlOverrideData::decl(),
         db::models::scratch::ScratchPayload::decl(),
         db::models::scratch::ScratchType::decl(),
         db::models::scratch::Scratch::decl(),
diff --git a/frontend/src/components/ui-new/containers/PreviewBrowserContainer.tsx b/frontend/src/components/ui-new/containers/PreviewBrowserContainer.tsx
index 55c0572a..c6d47cdd 100644
--- a/frontend/src/components/ui-new/containers/PreviewBrowserContainer.tsx
+++ b/frontend/src/components/ui-new/containers/PreviewBrowserContainer.tsx
@@ -2,6 +2,7 @@ import { useCallback } from 'react';
 import { PreviewBrowser } from '../views/PreviewBrowser';
 import { usePreviewDevServer } from '../hooks/usePreviewDevServer';
 import { usePreviewUrl } from '../hooks/usePreviewUrl';
+import { usePreviewUrlOverride } from '@/hooks/usePreviewUrlOverride';
 import { useLogStream } from '@/hooks/useLogStream';
 import { useLayoutStore } from '@/stores/useLayoutStore';
 import { useWorkspaceContext } from '@/contexts/WorkspaceContext';
@@ -19,7 +20,7 @@ export function PreviewBrowserContainer({
 }: PreviewBrowserContainerProps) {
   const navigate = useNavigate();
   const previewRefreshKey = useLayoutStore((s) => s.previewRefreshKey);
-  const { repos } = useWorkspaceContext();
+  const { repos, workspaceId } = useWorkspaceContext();
 
   const { start, isStarting, runningDevServers, devServerProcesses } =
     usePreviewDevServer(attemptId);
@@ -28,13 +29,19 @@ export function PreviewBrowserContainer({
   const { logs } = useLogStream(primaryDevServer?.id ?? '');
   const urlInfo = usePreviewUrl(logs);
 
+  // URL override for this workspace
+  const { overrideUrl, hasOverride } = usePreviewUrlOverride(workspaceId);
+
+  // Use override URL if set, otherwise fall back to auto-detected
+  const effectiveUrl = hasOverride ? overrideUrl : urlInfo?.url;
+
   const handleStart = useCallback(() => {
     start();
   }, [start]);
 
   // Use previewRefreshKey from store to force iframe reload
-  const iframeUrl = urlInfo?.url
-    ? `${urlInfo.url}${urlInfo.url.includes('?') ? '&' : '?'}_refresh=${previewRefreshKey}`
+  const iframeUrl = effectiveUrl
+    ? `${effectiveUrl}${effectiveUrl.includes('?') ? '&' : '?'}_refresh=${previewRefreshKey}`
     : undefined;
 
   const handleEditDevScript = () => {
diff --git a/frontend/src/components/ui-new/containers/PreviewControlsContainer.tsx b/frontend/src/components/ui-new/containers/PreviewControlsContainer.tsx
index 4259c3e3..3b8f1314 100644
--- a/frontend/src/components/ui-new/containers/PreviewControlsContainer.tsx
+++ b/frontend/src/components/ui-new/containers/PreviewControlsContainer.tsx
@@ -1,7 +1,8 @@
-import { useCallback, useState, useEffect } from 'react';
+import { useCallback, useState, useEffect, useRef } from 'react';
 import { PreviewControls } from '../views/PreviewControls';
 import { usePreviewDevServer } from '../hooks/usePreviewDevServer';
 import { usePreviewUrl } from '../hooks/usePreviewUrl';
+import { usePreviewUrlOverride } from '@/hooks/usePreviewUrlOverride';
 import { useLogStream } from '@/hooks/useLogStream';
 import { useLayoutStore } from '@/stores/useLayoutStore';
 import { useWorkspaceContext } from '@/contexts/WorkspaceContext';
@@ -18,7 +19,7 @@ export function PreviewControlsContainer({
   onViewProcessInPanel,
   className,
 }: PreviewControlsContainerProps) {
-  const { repos } = useWorkspaceContext();
+  const { repos, workspaceId } = useWorkspaceContext();
   const setLogsMode = useLayoutStore((s) => s.setLogsMode);
   const triggerPreviewRefresh = useLayoutStore((s) => s.triggerPreviewRefresh);
 
@@ -49,6 +50,32 @@ export function PreviewControlsContainer({
   const { logs: primaryLogs } = useLogStream(primaryDevServer?.id ?? '');
   const urlInfo = usePreviewUrl(primaryLogs);
 
+  // URL override for this workspace
+  const { overrideUrl, setOverrideUrl, clearOverride, hasOverride } =
+    usePreviewUrlOverride(workspaceId);
+
+  // Use override URL if set, otherwise fall back to auto-detected
+  const effectiveUrl = hasOverride ? overrideUrl : urlInfo?.url;
+
+  // Local state for URL input to prevent WebSocket updates from disrupting typing
+  const urlInputRef = useRef<HTMLInputElement>(null);
+  const [urlInputValue, setUrlInputValue] = useState(effectiveUrl ?? '');
+
+  // Sync from prop only when input is not focused
+  useEffect(() => {
+    if (document.activeElement !== urlInputRef.current) {
+      setUrlInputValue(effectiveUrl ?? '');
+    }
+  }, [effectiveUrl]);
+
+  const handleUrlInputChange = useCallback(
+    (value: string) => {
+      setUrlInputValue(value);
+      setOverrideUrl(value);
+    },
+    [setOverrideUrl]
+  );
+
   const handleViewFullLogs = useCallback(
     (processId?: string) => {
       const targetId = processId ?? activeProcess?.id;
@@ -77,17 +104,21 @@ export function PreviewControlsContainer({
     triggerPreviewRefresh();
   }, [triggerPreviewRefresh]);
 
+  const handleClearOverride = useCallback(async () => {
+    await clearOverride();
+  }, [clearOverride]);
+
   const handleCopyUrl = useCallback(async () => {
-    if (urlInfo?.url) {
-      await navigator.clipboard.writeText(urlInfo.url);
+    if (effectiveUrl) {
+      await navigator.clipboard.writeText(effectiveUrl);
     }
-  }, [urlInfo?.url]);
+  }, [effectiveUrl]);
 
   const handleOpenInNewTab = useCallback(() => {
-    if (urlInfo?.url) {
-      window.open(urlInfo.url, '_blank');
+    if (effectiveUrl) {
+      window.open(effectiveUrl, '_blank');
     }
-  }, [urlInfo?.url]);
+  }, [effectiveUrl]);
 
   const handleFixScript = useCallback(() => {
     if (!attemptId || repos.length === 0) return;
@@ -123,7 +154,13 @@ export function PreviewControlsContainer({
       activeProcessId={activeProcess?.id ?? null}
       logs={logs}
       logsError={logsError}
-      url={urlInfo?.url}
+      url={effectiveUrl ?? undefined}
+      autoDetectedUrl={urlInfo?.url}
+      isUsingOverride={hasOverride}
+      urlInputValue={urlInputValue}
+      urlInputRef={urlInputRef}
+      onUrlInputChange={handleUrlInputChange}
+      onClearOverride={handleClearOverride}
       onViewFullLogs={handleViewFullLogs}
       onTabChange={handleTabChange}
       onStart={handleStart}
diff --git a/frontend/src/components/ui-new/views/PreviewControls.tsx b/frontend/src/components/ui-new/views/PreviewControls.tsx
index 31520cd0..01ada55f 100644
--- a/frontend/src/components/ui-new/views/PreviewControls.tsx
+++ b/frontend/src/components/ui-new/views/PreviewControls.tsx
@@ -1,3 +1,4 @@
+import type { RefObject } from 'react';
 import {
   PlayIcon,
   StopIcon,
@@ -6,6 +7,7 @@ import {
   SpinnerIcon,
   CopyIcon,
   WrenchIcon,
+  XIcon,
 } from '@phosphor-icons/react';
 import { useTranslation } from 'react-i18next';
 import { cn } from '@/lib/utils';
@@ -24,6 +26,12 @@ interface PreviewControlsProps {
   logs: LogEntry[];
   logsError: string | null;
   url?: string;
+  autoDetectedUrl?: string;
+  isUsingOverride?: boolean;
+  urlInputValue: string;
+  urlInputRef: RefObject<HTMLInputElement>;
+  onUrlInputChange: (value: string) => void;
+  onClearOverride?: () => void;
   onViewFullLogs: () => void;
   onTabChange: (processId: string) => void;
   onStart: () => void;
@@ -44,6 +52,12 @@ export function PreviewControls({
   logs,
   logsError,
   url,
+  autoDetectedUrl,
+  isUsingOverride,
+  urlInputValue,
+  urlInputRef,
+  onUrlInputChange,
+  onClearOverride,
   onViewFullLogs,
   onTabChange,
   onStart,
@@ -73,11 +87,32 @@ export function PreviewControls({
         contentClassName="flex flex-col flex-1 overflow-hidden"
       >
         <div className="flex items-center gap-half p-base">
-          {url && (
+          {(url || autoDetectedUrl) && (
             <div className="flex items-center gap-half bg-panel rounded-sm px-base py-half flex-1 min-w-0">
-              <span className="flex-1 font-mono text-sm text-low truncate">
-                {url}
-              </span>
+              <input
+                ref={urlInputRef}
+                type="text"
+                value={urlInputValue}
+                onChange={(e) => onUrlInputChange(e.target.value)}
+                placeholder={autoDetectedUrl ?? 'Enter URL...'}
+                className={cn(
+                  'flex-1 font-mono text-sm bg-transparent border-none outline-none min-w-0',
+                  isUsingOverride
+                    ? 'text-normal'
+                    : 'text-low placeholder:text-low'
+                )}
+              />
+              {isUsingOverride && (
+                <button
+                  type="button"
+                  onClick={onClearOverride}
+                  className="text-low hover:text-normal"
+                  aria-label="Clear URL override"
+                  title="Revert to auto-detected URL"
+                >
+                  <XIcon className="size-icon-sm" />
+                </button>
+              )}
               <button
                 type="button"
                 onClick={onCopyUrl}
diff --git a/frontend/src/hooks/usePreviewUrlOverride.ts b/frontend/src/hooks/usePreviewUrlOverride.ts
new file mode 100644
index 00000000..54d6fb53
--- /dev/null
+++ b/frontend/src/hooks/usePreviewUrlOverride.ts
@@ -0,0 +1,86 @@
+import { useCallback } from 'react';
+import { useScratch } from './useScratch';
+import { useDebouncedCallback } from './useDebouncedCallback';
+import {
+  ScratchType,
+  type PreviewUrlOverrideData,
+  type ScratchPayload,
+} from 'shared/types';
+
+interface UsePreviewUrlOverrideResult {
+  overrideUrl: string | null;
+  isLoading: boolean;
+  setOverrideUrl: (url: string) => void;
+  clearOverride: () => Promise<void>;
+  hasOverride: boolean;
+}
+
+/**
+ * Hook to manage a per-workspace preview URL override.
+ * Uses the scratch system for persistence.
+ */
+export function usePreviewUrlOverride(
+  workspaceId: string | undefined
+): UsePreviewUrlOverrideResult {
+  const enabled = !!workspaceId;
+
+  const {
+    scratch,
+    updateScratch,
+    deleteScratch,
+    isLoading: isScratchLoading,
+  } = useScratch(ScratchType.PREVIEW_URL_OVERRIDE, workspaceId ?? '', {
+    enabled,
+  });
+
+  // Extract override URL from scratch data
+  const payload = scratch?.payload as ScratchPayload | undefined;
+  const scratchData: PreviewUrlOverrideData | undefined =
+    payload?.type === 'PREVIEW_URL_OVERRIDE' ? payload.data : undefined;
+
+  const overrideUrl = scratchData?.url ?? null;
+  const hasOverride = overrideUrl !== null && overrideUrl.trim() !== '';
+
+  // Debounced save to scratch
+  const { debounced: debouncedSave } = useDebouncedCallback(
+    async (url: string) => {
+      if (!workspaceId) return;
+
+      try {
+        await updateScratch({
+          payload: {
+            type: 'PREVIEW_URL_OVERRIDE',
+            data: { url },
+          },
+        });
+      } catch (e) {
+        console.error('[usePreviewUrlOverride] Failed to save:', e);
+      }
+    },
+    300
+  );
+
+  const setOverrideUrl = useCallback(
+    (url: string) => {
+      debouncedSave(url);
+    },
+    [debouncedSave]
+  );
+
+  const clearOverride = useCallback(async () => {
+    try {
+      await deleteScratch();
+    } catch (e) {
+      // Ignore 404 errors when scratch doesn't exist
+      console.error('[usePreviewUrlOverride] Failed to clear:', e);
+    }
+  }, [deleteScratch]);
+
+  return {
+    overrideUrl,
+    isLoading: isScratchLoading,
+    setOverrideUrl,
+    clearOverride,
+    hasOverride,
+  };
+}
diff --git a/shared/types.ts b/shared/types.ts
index ef2ea5e1..f328fb46 100644
--- a/shared/types.ts
+++ b/shared/types.ts
@@ -64,9 +64,11 @@ export type DraftWorkspaceData = { message: string, project_id: string | null, r
 
 export type DraftWorkspaceRepo = { repo_id: string, target_branch: string, };
 
-export type ScratchPayload = { "type": "DRAFT_TASK", "data": string } | { "type": "DRAFT_FOLLOW_UP", "data": DraftFollowUpData } | { "type": "DRAFT_WORKSPACE", "data": DraftWorkspaceData };
+export type PreviewUrlOverrideData = { url: string, };
 
-export enum ScratchType { DRAFT_TASK = "DRAFT_TASK", DRAFT_FOLLOW_UP = "DRAFT_FOLLOW_UP", DRAFT_WORKSPACE = "DRAFT_WORKSPACE" }
+export type ScratchPayload = { "type": "DRAFT_TASK", "data": string } | { "type": "DRAFT_FOLLOW_UP", "data": DraftFollowUpData } | { "type": "DRAFT_WORKSPACE", "data": DraftWorkspaceData } | { "type": "PREVIEW_URL_OVERRIDE", "data": PreviewUrlOverrideData };
+
+export enum ScratchType { DRAFT_TASK = "DRAFT_TASK", DRAFT_FOLLOW_UP = "DRAFT_FOLLOW_UP", DRAFT_WORKSPACE = "DRAFT_WORKSPACE", PREVIEW_URL_OVERRIDE = "PREVIEW_URL_OVERRIDE" }
 
 export type Scratch = { id: string, payload: ScratchPayload, created_at: string, updated_at: string, };