Solo-founder SaaS security checklist before launch

You are the only reviewer, so split the work

A solo founder SaaS security checklist before launch has one constraint a team checklist does not: there is no second person to review anything. You wrote the code, or an AI builder wrote it for you, and you are also the only one who will check it before the URL goes public. Your time and budget are limited, so the useful move is not to inspect everything equally. It is to split the work by what can be inferred from outside the app versus what cannot.

Two kinds of problem hide in a pre-launch app. One kind is visible to anyone who loads the public URL: missing security headers, source maps, secret-shaped strings in the client bundle, a storage bucket that lists its contents, a route that renders without a login. The other kind is invisible from outside: whether one logged-in user can read another user's data, whether a paid feature actually checks the subscription, whether your business rules hold under inputs you did not test.

The first kind is cheap to clear because it is observable and reproducible. The second kind is expensive because it needs someone to read the code and reason about intent. Confusing the two is how solo founders waste their limited review time. Clear the cheap half fast, then spend the budget you have left on the half that needs a human.

The half you can delegate to a public-surface scan

Everything below is observable from the production URL without an account. A scan, or a careful manual pass from a clean browser session, can confirm each one. These are mostly configuration and deployment defaults, which is exactly the class an AI builder gets wrong because the generated app is tuned for a working demo, not a hardened production surface. Treat the launch-blocker items as reasons to delay the public post; treat the hardening items as fixes you can ship shortly after.

The shared trait of this list is that the answer comes from the outside. You do not need to understand the app's intent to judge it, only to read the response. That is why it is safe to delegate to an automated pass and clear quickly.

• Security headers. Confirm the deployed responses set Content-Security-Policy, X-Content-Type-Options: nosniff, frame protection, and a deliberate Referrer-Policy. Missing headers are a hardening task on most apps, a launch blocker if the app embeds third-party content or handles sensitive sessions.
• Source maps. Check whether production JavaScript references public .map files. A source map is not automatically a breach, but treat it as a launch blocker when it exposes internal API paths, admin route names, or secret-handling logic, and a hardening task otherwise.
• Secret-shaped strings in the bundle. Search the loaded client JavaScript for keys that should never reach the browser, such as a service-role token, a private API key, or an SMTP password. A live secret in the bundle is a launch blocker, full stop, because anyone can read it.
• Storage-bucket visibility. Open a known asset URL and try to list the bucket or fetch a neighbor object you should not see. A publicly listable or readable private bucket is a launch blocker.
• Routes that load without auth. Visit app and admin routes directly in a logged-out session and watch what renders. A protected page that returns data without a session is a launch blocker; one that flashes a layout before redirecting is a hardening task.
• Open or wildcard CORS. Check whether public API responses send a permissive Access-Control-Allow-Origin. Wildcard CORS on an authenticated endpoint is a launch blocker; on a fully public read-only endpoint it is a hardening task.

The half that genuinely needs a human

None of the items below can be inferred from the public surface. They depend on what the app is supposed to do, and only someone who reads the code or models the data flow can tell whether it does it. This is where a paid manual review or code review earns its cost, and where a scan will return a clean result that means nothing about these risks. Map each to the OWASP categories for broken access control and business-logic flaws if you want a taxonomy, but the point is simpler: these need a reader, not a scanner.

If your budget allows one paid thing before launch, spend it here. A scan cannot substitute for it, and these are the failures that turn into the worst incidents because they leak real customer data or real money.

• Authorization logic. Authentication proves who you are; authorization decides what you may do. A scan can see that a login exists. It cannot tell whether the endpoint behind it checks that this user owns the record they requested. Verifying that one user cannot act on another's resource is a launch blocker and a manual job.
• Entitlement and billing enforcement. Whether a paid feature actually checks the subscription, whether a cancelled plan still grants access, whether a price or quota is enforced server-side rather than hidden only in the UI. These are business rules in your code; the public surface reveals none of them. Bypassable paid features are a launch blocker for a SaaS.
• Multi-tenant data isolation. If two customers share a database, the boundary that keeps tenant A from reading tenant B lives in your queries and access rules, not in any header. A missing tenant filter is invisible from outside and a launch blocker. Confirming it needs someone to trace the data path.
• Business rules under unexpected input. Negative quantities, replayed requests, skipped steps in a flow, values changed in transit. Whether these break your logic depends entirely on what the logic is meant to enforce, which only a human reviewing the code can judge.

How to run it without a teammate

Work the two columns in order, because the first one is fast and changes how much time you have for the second. Run the public-surface checks first: a scan or a clean-browser pass clears most of them in one sitting and gives you a short list of concrete fixes. Resolve the launch blockers there, leave the hardening tasks on a list for the week after launch, and re-run the pass to confirm the blockers are gone.

Only then spend your remaining time or budget on the human half. You can do some of it yourself by reading the specific code paths that handle authorization, billing, and tenant boundaries, even without a security background, because you know what the app is supposed to enforce. If you can pay for one review, scope it tightly to those paths rather than asking for a vague full audit. A focused two-hour code review of authorization and entitlement is worth more to a solo founder than a broad scan of everything.

Where VibeCodeGuard fits, and where it does not

VibeCodeGuard's Launch Check covers the first column in one pass: security headers, source maps, secret-shaped strings in the client bundle, storage-bucket visibility, and routes that load without auth, plus severity and fix guidance. For a solo founder, the value is that it clears the cheap, observable half quickly so your limited time and budget go to the half that needs a person.

The second column is explicitly out of scope, and naming that is the point. Launch Check is not a penetration test, a code review, or a business-logic audit. It does not evaluate authorization logic, entitlement and billing enforcement, business rules, or multi-tenant data isolation, because none of those can be inferred from the public surface. When the real check needs someone to read the code, this article and the scan both say so plainly.