By You can fix this yourself. Settings and publish steps inside Lovable and Supabase.
- How serious
- High
- Fix it yourself?
- Yes, you can fix this yourself
- Typical cost
- $49–$800 one-off check, or €99–$990 for a single fix (prices)
- Top rated for Lovable
- Afterbuild Labs · 10.0/10
A Lovable app that works in the preview and breaks on the live site is usually fine as code. What differs is the published snapshot, the domain setup, the sign-in redirect addresses, or the database access rules. You can check all four yourself in Lovable and Supabase.
What you see, and what it usually means
| What you see | What it usually means |
|---|---|
| The preview works, the live site shows a blank page or an old version. | The published snapshot is older than the preview, or the domain is not Live yet. |
| Sign-in works in the preview and fails on your custom domain. | The new address is missing from the allowed redirect URLs, or the Site URL still points to localhost. |
| Your old website appears on the new domain. | Leftover A, AAAA or CNAME records still point at the previous host. |
| Data shows in the preview but the live site shows empty lists. | Access rules are on with no policies, or the live app points at a different backend. |
| You pushed changes to GitHub and nothing changed on the live site. | Pushing does not publish. The live site changes only when you publish from Lovable. |
Why it happens
Lovable runs your app in two places. The preview is a live build of your current project. Publishing deploys a snapshot to its own URL, so anything changed after the last publish is not on the live site. That alone explains many "it works in preview" reports.
The second gap is the address. Sign-in, password reset and confirmation emails redirect to an address the backend must trust. Lovable Cloud adds custom domains for you. If you connected your own Supabase project, you must add the live address there yourself. Supabase calls that setting "critical for email confirmations and password resets" and ships it set to localhost.
The third gap is data access. Supabase returns no rows through the public key when Row Level Security is on but no policy exists. The AI often enables RLS and forgets the policy, so the preview you tested as the owner looked fine and real users see nothing.
Check these first
Sign-up confirmation and password reset work end to end
Use a real inbox. Check that the link arrives, points to your live domain, and works once.
Access rules are on for every table
In Supabase, open Table Editor: every table should show RLS enabled, with at least one policy. In Firebase, your rules should never say allow read, write: if true.
Secrets live in the host's environment settings
Keys belong in environment variables on the server, not in the repository or in front-end code.
The code lives in a Git repository you own
Connect GitHub or export the project. If the builder account is lost, the product should not be.
Errors reach you before users do
Add error monitoring and uptime alerts. If you learn about outages from customers, this is missing.
Fix it yourself
- Open the Publish dialog in Lovable and publish again. The live site only updates when you publish, and the dialog is blocked while the latest build fails, which tells you the real problem is a build error.
- Go to Project → Settings → Domains and check the status. It moves from Verifying to Setting up to Live, and the domain serves nothing until it is Live and the project is published. DNS can take up to 72 hours.
- At your DNS provider, remove old A, AAAA or CNAME records for the same name. Lovable needs one A record pointing to 185.158.133.1 and one TXT record with the
lovable_verify=value from the setup window. - If you use your own Supabase project, open Authentication → URL Configuration. Set the Site URL to your live address and add it to Redirect URLs. Then test a password reset with a real inbox.
- In the Supabase Table Editor, open each table that shows empty on the live site. If RLS is on with no policies, ask Lovable in Chat mode to add policies that compare the row owner to
auth.uid(), then test with two accounts. - Open the live site, press F12, and read the Console tab. Paste the first red error into Lovable with "investigate before changing code". If a recent change caused it, use Revert to this version instead of fixing forward.
When to get a human engineer
Get a human engineer when the live site has been down for more than a day, when sign-in fails for real customers, or when you cannot tell which gap you have. A one-off check costs $49 to $800, takes a day to a week, and names the cause. A single fix, such as redirect URLs plus missing policies, is in the €99 to $990 band and takes about two days. If the site has been patched by prompts for months, read fix or rebuild before paying for another round.
Top-rated companies for Lovable apps
Ranked by our score: published prices, scope of work, AI tools named, timing and a low-risk first step. How we score.
- 1Afterbuild Labs10.0/10Best for: A check before launchFree first step · from $49
- 2Redlab10.0/10Best for: A full rescue by one team that keeps buildingFree first step · from $490
- 3Vibe Code Rescue (Lev Arakelyan)9.0/10Best for: A one-off check and a cleanupFrom $299
Questions
Why is my Lovable app showing a blank page after publishing?
Most often the published snapshot is from before the fix, the domain is not Live yet, or the build failed and the Publish dialog is blocked. Check the Console tab on the live site for the exact error first.
Why does sign-in work in the preview but not on my domain?
Because the live address is not on the allowed redirect list in your backend. Lovable Cloud adds it for you. Your own Supabase project needs the Site URL and Redirect URLs updated by hand.
Can I export my Lovable app to GitHub and fix it there?
Yes. Git sync is on all plans and works both ways. Commits to the synced branch appear in Lovable, but pushing does not publish, and changed Edge Functions and migrations still need a deploy from Lovable.
Sources: Lovable docs: Launch on a custom domain; Lovable docs: FAQ (publishing, Try to fix, status page); Lovable docs: Git sync overview; Supabase docs: Redirect URLs and Site URL; Supabase docs: Row Level Security.