Base44 App Not Loading? Fix the Blank Screen (2026)

Start Here: Where Does Your Base44 App Fail to Load?

Open your app in each place below and note where it breaks. That tells you which section to read.

Before any of them, do these four checks. They take a few minutes and rule out the causes that no change to your app can fix.

1. Is Base44 down? Open status.base44.com. If there is an active incident, wait for it to clear before you change anything.
2. Is it your browser? Open the app in an incognito window with extensions turned off, or in another browser or device. Check that your connection is stable.
3. Did it break right after a prompt? Then the last AI change is the prime suspect. Go straight to Error 1 and revert it.
4. What does the console say? Press F12 (Windows) or Cmd+Option+J (Chrome on Mac) and look at the red errors. You don't need to understand them: a screenshot of them is the most useful thing you can send to support or a developer.

Error 1 - Base44 App Shows a Blank or White Screen

What you see: a white page, a loading spinner or only the header, in the preview and on the published link. Sometimes the app loads for a moment and then disappears, or turns white when you click something. It can happen on desktop and on mobile.

Why it happens

Base44 says most of these cases come from a problem in the app's code or a temporary platform issue. Two code causes are worth checking first:

• A recent AI change broke the code. Suspect this first if the app worked before your last prompt.
• Your field definitions and the saved data don't match. This often shows up after publishing, sometimes with the error Uncaught Error: Error in json schema: properties is required for object type in the console.

How to fix it

1. Refresh the page, then open the app in a new browser window. If it still fails, clear your browser cache and cookies and load it again.
2. If the app broke after a prompt, click the Revert icon on that chat message, or open Version History (the clock icon in the AI chat) and restore the last version that worked. Asking the AI to "revert" in a chat message is not the same thing. Reverting restores an earlier version of the app; don't assume it brings back records a change deleted or edited, so check your data afterwards.
3. If only part of the app turns white, for example after clicking a button, describe it to the AI chat precisely: where you clicked, what happened and when it started.
4. If the console shows the JSON schema error, check your field definitions: each field's type has to match the kind of value the app saves in it.
5. Ask for the change you wanted again, in a smaller prompt.

What you should see: the page renders and the console shows no red errors.

Special case: Failed to load app: Error serializing to JSON: UnicodeEncodeError appears when the app name contains an emoji or an unsupported special character. You can't open or rename the app yourself in that state, so contact Base44 support.

Error 2 - The Preview Works but the Published App Is Blank or Outdated

What you see: everything looks right in the editor preview, but the published link shows a blank page or an older version of the app.

Why it happens

• The publish didn't finish, or you never clicked Publish after the last change.
• You made the changes on a branch. Base44 always publishes from main.
• Your browser or device is still showing a cached copy.
• A mismatch between field definitions and saved data, which Base44 says can show up as a blank screen after publishing (Error 1).

How to fix it

1. Click Publish again and wait for the success message.
2. If you are working on a branch, the Publish button is replaced by Merge to main. Merge first, then publish.
3. Clear your browser cache and open the published link on another device or browser.
4. If the change involved a backend function, redeploy it from the dashboard and check its error logs.

What you should see: the published link, opened on a second device, shows the same version as the preview.

Error 3 - The App Loads for You but Not for Other People

What you see: you can open the app, but other people, or you in a logged-out window, get a sign-in screen, a request-access pop-up or an empty page.

Why it happens

• App Visibility. A Private app opens only for invited people, and a Workspace app only for members of your Base44 workspace. When someone else opens a shared link to a private app, they see a pop-up asking them to request access.
• The app loads but looks empty. If you created records with Test Data turned on, they live in a separate test database. The published app always reads production data, so those records don't appear there.

How to fix it

1. Open the app in an incognito window while logged out. That is what your users see.
2. If the app is meant for specific people, keep it Private and invite them by email from Dashboard → Overview → Invite Users.
3. Switch to Public only if the app is meant for anyone on the internet, because a Public app doesn't require sign-in. First open Security in the dashboard and run the security scan, then go to Overview → App Visibility and select Public.
4. If the app is empty for users, check whether your data exists in production and not only in testing mode (Dashboard → Settings → Advanced Capabilities shows the Test Data option).

What you should see: in a logged-out incognito window, a Public app opens, and a Private app shows a sign-in screen until the person is invited. For login and invitation problems in more depth, see why a Base44 app works for you but not for others.

Error 4 - Base44 Is Stuck on Loading Your App

What you see: the Base44 editor stays blank or shows a loading icon that never finishes, so you can't even reach your app to fix it.

Why it happens

This is usually the editor, not your app: an outdated browser, cached data, an extension such as an ad blocker, or a Base44 incident.

How to fix it

1. Open the editor in an incognito window with extensions off. If it opens there, clear your cache and Base44 cookies (this signs you out) in your normal browser, and turn extensions back on one by one.
2. Update your browser to the current version.
3. Check the status page and the Base44 Discord for a reported outage.
4. If the editor opens but the AI chat is frozen, Base44 suggests changing the AI model in your app settings, switching to Discuss mode and sending a short message such as "hi", or making a tiny manual change in Edit mode to force a state change. The full walkthrough is in Base44 stuck on "Thinking"?

What you should see: the editor opens in an incognito window. If it does there but not in your normal browser, the cause is in your browser profile, not in your app.

Error 5 - The App Loads, but Only After a Long Spinner

What you see: the app does load in the end, but visitors stare at a spinner or a blank page for several seconds first.

Why it happens

According to Base44, the most common causes are heavy content at the top of the page, large scripts and unoptimized images or video. Any file that takes more than 1-2 seconds to load is a likely culprit.

How to fix it

1. Measure the published app, not the builder preview. Run it through PageSpeed Insights, or open Chrome DevTools, go to the Network tab, reload and sort by time.
2. Compress and resize images before you upload them, and ask the AI to lazy-load images that are further down the page.
3. Host videos on YouTube or Vimeo instead of uploading them, and turn off autoplay and loop on large background videos.
4. Move videos, long data lists and other heavy sections below the first screen.
5. Ask the AI, in Discuss mode first, to remove scripts and styles the app no longer uses.

What you should see: PageSpeed Insights reports Largest Contentful Paint at 2.5 seconds or less, Cumulative Layout Shift at 0.1 or less and Interaction to Next Paint at 200 milliseconds or less, which are the targets Base44 gives.

Error 6 - The Default Link Works but Your Custom Domain Doesn't

What you see: the app loads on its default Base44 link, but your own domain shows an error, a 404 on newer pages or a certificate warning.

How to fix it

1. Confirm the app loads on the default Base44 link. If it does, the app is fine and the problem is the domain.
2. If your domain uses Cloudflare, set the Base44 records to DNS only (grey cloud). With the proxy on, new pages return 404 on the custom domain.
3. For pending verification, DNS records and SSL errors, follow the step-by-step in custom domain not working in Base44.

What you should see: the custom domain shows the same version as the default link, over https and with no warning.

Fixes That Don't Apply to Base44: Supabase, Environment Variables and CORS

Many blank-screen guides, including an older version of this one, recommend fixes from other stacks. Base44 includes its own backend: database, authentication, file storage, backend functions and hosting, with row-level and field-level security built in. It doesn't run on Supabase. So:

• Supabase RLS policies and anon keys only matter if your backend functions call an external Supabase project you connected yourself.
• Public environment variables with a framework prefix belong to Next.js or Vite projects, not to Base44 apps. Base44 stores API keys as Secrets, which backend functions read at runtime; setting a secret redeploys the functions that use it.
• Separate Development and Production environments for variables are not something the Base44 docs describe. The separation Base44 does document is between test data and production data (Error 3).
• Opening up CORS is not a documented fix for a Base44 app that won't load, and loosening it can expose your backend to other sites.

When It Isn't a Bug

• Base44 hosts single-page apps. No prompt turns the app into server-rendered pages. If you need that for SEO or link previews, that is a platform limit, not a bug you can fix.
• Every fix creates a new blank screen. Stop prompting, restore the last version that worked from Version History, and make the change again in small steps.

What to Include When You Ask for Help

Whether you write to Base44 support or to a developer, include:

• the app name and link;
• where it fails (editor, preview, published link, custom domain, only for other people) and on which browser, device and operating system;
• when it started and the last change or prompt before it;
• what triggers the white screen, if anything, such as a specific button or page;
• screenshots of the screen and of the red errors in the browser console, with user data cropped out and never any passwords or API keys.

Frequently Asked Questions

Still broken after this guide?

If your Base44 app keeps failing in ways this guide doesn't cover, the AppStuck Master Prompt gets your AI builder to write up the problems in your app, so you can see what's wrong before you change anything else. It's free. Get the Master Prompt.

Sources

Checked on September 16 and 28, 2026:

• Base44 docs: Troubleshooting issues
• Base44 docs: Optimizing app performance
• Base44 docs: Backend features
• Base44 docs: secrets set
• Base44 docs: Managing access
• Base44 docs: Testing your data
• Base44 docs: Working with branches
• Base44 status page