There's a moment with every project that feels smaller than it is: the first time you post a real, public link instead of sending it to two friends who already know it's rough. Nothing about the code changes in that moment. Everything about who's looking at it does.
Why this moment is the one that matters
While you're the only one testing an app, you're also the only one who could possibly exploit it, and you already have every password and every piece of data in it. There's no meaningful attack surface because there's no meaningful attacker. The instant a public link goes out, that assumption quietly stops being true, and most of what got skipped during building gets skipped precisely because it didn't matter yet.
The code doesn't know the difference. Only you do, and only if you stop to check.
What to check in the hour before you post the link
- Log in as two separate test accounts and try to view one account's data while signed in as the other. This single check catches more real bugs than anything else on this list.
- Open a private browser window with nobody logged in and try to reach every admin or internal page directly by URL. It should refuse you completely, not just hide a button.
- Search your codebase and your deployed build for anything that looks like a key or secret, and confirm nothing sensitive ships to the browser.
- Go table by table through your database's access rules and confirm each one is actually turned on, not just present in the settings.
- Check what a signup form does if the same email tries to register twice, and what a login form does after ten wrong password attempts in a row.
What doesn't need checking yet
This isn't a call to gold-plate everything before you ever show anyone your work. A five-person beta with people you know personally carries a different risk profile than a public link dropped into a group of strangers. The five checks above are the ones that matter regardless of scale, because they're the ones that turn "embarrassing bug" into "someone else's data got exposed." Everything else can wait for the next milestone.
What actually changes at this moment isn't your code. It's who's allowed to find out what your code does when nobody's watching. That's worth twenty minutes before you hit send on the link, not twenty minutes of regret after someone else finds the gap first.