Monitoring for Lovable apps
Monitoring for Lovable apps
Lovable builds you a full-stack app (React + Supabase) from a text description. You can go from idea to deployed in an afternoon. But once it's live, you're flying blind.
You're not reading the generated code line by line. Nobody is. So when a refactor quietly breaks your onboarding flow or a Supabase edge function starts throwing, you find out from a user, not from Lovable.
What goes wrong
Lovable modifies code across your whole app when you ask for changes. The preview looks right, but there are things it won't catch.
The most common one is refactors that touch too much. You ask Lovable to change a feature, it edits five files, the settings page works now but the signup flow is broken. Nothing in the preview warns you.
Supabase edge functions are sneaky too. When a server-side function throws, the frontend just shows a blank state or a vague error. The user leaves. You have no logs telling you what happened.
Then there's the stuff Lovable doesn't even know exists. Your Stripe webhooks, your email provider, your analytics pixel. Lovable restructures your components and those integrations quietly stop working. Pages load fine. Revenue doesn't.
And plain old JS errors. A component throws, React catches it, and the user gets a white page or a spinner that never stops. The Lovable preview didn't show this because it wasn't running under real traffic.
Setup (30 seconds)
Paste this into your Lovable chat:
Add these two script tags to the
<head>inindex.html— both are needed. The first buffers any errors that fire before the main snippet loads:<script>window.__ufq=[];window.addEventListener("error",function(e){window.__ufq.push(e)});window.addEventListener("unhandledrejection",function(e){window.__ufq.push(e)})</script><script src="https://upflag.io/api/v1/snippet?key=uf_YOUR_KEY" defer></script>— replace uf_YOUR_KEY with your key from the Upflag dashboard.
Or open index.html and add them yourself. Sign up at upflag.io to get your project key.
That's it. Errors start showing up in your dashboard immediately. Set up alerts (email, Slack, or SMS) so you don't have to check manually. Alerts tell you what broke in plain English, not a stack trace.
Upflag also checks your URL every 60 seconds. If your Lovable app goes down, you'll know before your users do.
Connecting Lovable's MCP server (paid Lovable plans)
If you're on a paid Lovable plan, you can connect Upflag as a custom MCP server. Go to Settings, Connectors, Personal connectors, click "New MCP server," and add your Upflag MCP endpoint from your dashboard under Integrations. Use bearer token auth with your API key.
Once connected, Lovable can see what's actually breaking in production before it starts editing code. Instead of you describing the bug, the agent reads the error data itself and starts from there. Makes the fix loop a lot tighter.
The MCP connection doesn't replace the script tags. The tags capture errors. The MCP connection lets Lovable read them.