How to know if your app's signup is broken (before a user tells you)
Signup can break while your homepage looks fine. Six quick checks for Lovable, Bolt, Replit and Cursor apps, plus a free one-page health check.
Free check first: paste your signup page URL into FunnelSitter's free check. A real browser opens that one page and reports the HTTP status, console errors, broken links, unfinished buttons, load time, and a screenshot. No account needed; an email is asked for only on the result page, and only if you want the result sent.
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Be clear on what it does: the free check looks at one page. It does not fill in or submit your signup form. Walking the full signup, login or checkout flow on a schedule is what a FunnelSitter monitor does, after you prove you own the domain.
Why signup breaks quietly in AI-built apps
Apps built with Lovable, Bolt, Replit or Cursor change fast. One prompt can rewrite the auth code, move a route, or rename an environment variable. Your homepage still returns 200, so an uptime monitor stays green, while the signup form is gone, throws an error, or never finishes. Most founders find out from a customer email, or not at all.
Six checks you can do in ten minutes
- Open the signup page on the live URL, not the preview. Builder previews often use different auth settings than your custom domain. Test where your users actually arrive.
- Open the browser console while you load the page. A red error on load (a missing env var, a failed script, a blocked request) is the most common early sign that the form won't work. The free check reports these for you.
- Look for an unfinished or dead button. AI edits sometimes leave a "Sign up" button with no handler, a
#link, or placeholder text. Click it once and watch what happens. - Sign up with a fresh email address. Use an address you have never used in the app, and see whether you land on the right page and whether the confirmation email arrives.
- Check your auth provider's redirect settings. If you use Supabase auth, the Site URL and Redirect URLs must include your live domain, not only the preview domain. A mismatch often sends new users back to the start or to an error page.
- Log out and log back in. A signup that "works" but leaves users unable to log in is still a broken signup.
How to keep catching it
- After every AI edit or deploy, re-run the free check on your signup page. It takes one paste and shows the screenshot and console errors.
- For ongoing coverage, a FunnelSitter monitor follows the steps you describe (visit, click, fill, submit, check the text or URL) once you have verified the domain. On the free plan it checks one flow once a day and emails you only after two failures in a row, with a screenshot and a paste-ready fix prompt for Cursor or Lovable.
Limits worth knowing
- FunnelSitter's bot cannot solve captchas. A step that stops on a captcha fails.
- It cannot finish an email-confirmation step, because its example.com test addresses do not receive mail.
- Test accounts created by a monitor stay in your app; FunnelSitter does not delete them.
FAQ
Does the free check test my signup form? No. It loads one page and checks its health. Testing the full flow needs a monitor and a verified domain.
Do I need an account for the free check? No. You paste a URL. An email is optional and only asked for on the result.
Which builders does it work with? Any public URL. It is made for apps built with Cursor, Lovable, Bolt, Replit and v0.