Building the API request tester for Quietbench, the desktop version came together fast — headers, body, response view, done. Mobile is where I actually lost time.
The CORS warning banner. On desktop, a dismissible banner explaining a blocked request has plenty of room. On a narrow viewport, it either pushed the actual response out of view or got truncated into something unreadable.
Fix was less about styling and more about rethinking the banner as collapsible-by-default on small screens, expandable on tap — not just shrinking the same layout down.
The URL input row. Method dropdown + URL field + Send button in one row is fine until the viewport gets narrow enough that the URL field shrinks to a few visible characters. Testing a real API URL when you can see 8 characters of it is useless.
Ended up stacking the method selector above the URL field on small screens instead of forcing everything into one row no matter what.
