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 catches common secrets that leaked into your deployed front-end code and detects a Supabase or Firebase backend from your front-end. What it still can't see, and what needs a direct look, is whether your data is readable without a login, 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
- 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. We record which domain was checked and keep anonymous result statistics; see our privacy policy.
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 in your front-end, it notes that but never queries it and never reads 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 detects that from your front-end. Testing whether it is readable without a login, and who can write or change it, 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
Go deeper than the free check on your Replit app
A full Secvura Application Security Review is a hands-on assessment that reaches the inside risks an external check can’t: who can write or change your data, your storage and access-control logic, and the flaws that actually cost teams real money, with a clear plan your team can act on the same day.
£1,200
fixed price · report in 1–2 weeks · reply within one working day
Not ready? Start with the free Surface Check and see the quality of the findings first.