Security for apps built on Replit
Replit's agent can build and host a full app from a prompt. That convenience is also how secrets end up exposed and data ends up public. Start with a free external snapshot, then check what lives inside.
Built and hosted in one place, exposed in one place too
Because Replit builds and deploys together, it is easy to ship quickly, and just as easy to ship with a secret committed into the code, a database left open, or default settings that expose more than you intended. The app runs fine either way, which is why these slip through.
The outside view can’t see this
Secrets in your code, and who can change your data
The free Surface Check now catches common secrets that leaked into your deployed front-end code, and detects a Supabase or Firebase backend to test, read-only, whether its data is readable without a login. What it still can't see, and what needs a direct look, is a secret sitting in a private repl or your server code, and whether your data can be written or changed without permission by someone who shouldn't.
What the free Surface Check covers for your Replit app
- Database access: we detect a Supabase or Firebase backend from your front-end and test, read-only, whether any of your data is readable without a login.
- HTTPS and HSTS on your custom domain, so traffic can't be silently downgraded to plain HTTP.
- Security headers (Content-Security-Policy, clickjacking protection, nosniff) on your front-end.
- Your TLS certificate's health and how soon it expires.
- Cookie flags (HttpOnly, Secure, SameSite) on any session or auth cookies you set.
- Email spoofing: SPF, DKIM and DMARC on your domain, so attackers can't send email as you.
- Exposed secrets: common API keys or tokens (such as a Supabase service_role or Stripe secret key) left in the front-end code your site serves to browsers.
See your external surface in about a minute
A free, passive snapshot with an A-to-F Surface Score and every issue scored by severity and fix effort. No sign-up, and nothing is stored.
Run the free Surface Check →Frequently asked
Does the check log into my Replit project?
No, it never signs in, never uses a secret key, and never reads your code. The passive checks read only your public external surface: headers, TLS, cookies and DNS. If it detects a Supabase or Firebase backend, it uses the public config your app ships to test, read-only, whether your data is readable without a login, without ever reading your actual data.
Where should my secrets live?
In Replit's secrets manager (environment variables), never committed into the code or left in a public repl. Any secret that has been public should be rotated.
How would I know if my data is open?
If your data is behind Supabase or Firebase, the free check now detects it and tests, read-only, whether it is readable without a login. For any other datastore, or to check who can write or change your data, that needs a direct look, which a full Secvura review does as standard.
Is it free?
Yes, free and with no sign-up, with an A-to-F Surface Score and every issue scored by severity and fix effort.
More free checks