My App Works for Me, Why Does It Break for Other People?
6 min read
Your app works flawlessly for you and breaks the moment a friend opens the link. The reason, in one sentence: you are not a fresh user. Your browser, your login, and the data you created while building are all quietly propping the app up. A stranger arrives with none of that support, and the cracks show instantly.
Why this happens
You have been the only person to touch this app since it existed. Along the way you built up a private set of advantages a new user does not have:
- You are already logged in, so you never see the signup and login flow the way a stranger does.
- Your account is full of data you created by hand, so screens that assume data exist look fine. A brand-new account has empty screens.
- Your browser has cached files and stored tokens from every version you ever loaded, so it silently patches over things a clean browser cannot.
- You test on your device, your network, your screen size, so a phone on patchy wifi never enters the picture.
An AI agent building "let users see their dashboard" builds the dashboard for an account that already has data, because yours did. It never built the empty version, the first-signup version, or the slow-network version, because you never asked and the demo worked without them.
How to check
Do not trust your own browser for this. Reproduce a real stranger's first minute:
- Open a private / incognito window, or better, a different browser you never use for this app. This strips your login and cache.
- Go to the live URL and sign up as a brand-new user with an email you have never used here. Watch every screen from zero.
- Now open the same link on your phone, on mobile data, not your home wifi.
- Write down every place it looks broken, blank, stuck, or confusing. Those are the exact things your first real users will hit.
If the app looks great for you but this run is full of blank screens and dead ends, that gap is the whole problem.
The fix
- Test as nobody. Make the incognito, new-account, phone run above part of how you check every change, not a one-off. If it breaks there, it is broken.
- Handle the empty account. Every screen that shows a list or a number needs a deliberate "you have nothing yet" state with a next step, not a blank box. See empty states.
- Delete your seed and test data, then look again. If the app falls apart without the rows you hand-made, real users get that broken version.
- Force a fresh load. Do a hard refresh (or test in a clean browser) so you see what someone with no cache sees. Production behaves differently from your machine; that is its own issue, covered in works locally but broken in production.
- Fix on the real device. Reproduce each problem in the clean run, fix it, and confirm the fix in the same clean run, not in your logged-in main browser.
The trap to avoid
Do not "fix" a bug by refreshing your own browser until it goes away, or by adding the missing data back to your account. That hides the symptom from you and leaves it fully intact for everyone else. If the only way to make a screen work is to already have data or already be logged in, the fix is to build the version that does not, not to arrange for yourself to never see it.
Where this fits
"Works on my machine" is the single most common reason a demo that dazzled you falls flat with real users. The whole job of getting beta-ready is closing the gap between your privileged view and a stranger's first minute. The free Readiness Report runs the checks as an outsider would, on your real project, and tells you where a fresh user hits a wall. When you want the fixes handed to you in order, that is the Finishing Pass. It pairs well with testing an app only you have used and knowing when a demo is actually launch-ready.