Developer Tools

Getting started with Firefox DevTools (2)

Welcome! This forum is for discussing Firefox’s built-in developer tools which are used for inspecting and debugging websites. Check out for more about our community and ways to get involved. Brush up…

I am getting a warning and I don't know what it means (5)
Mistakes when opening Network > response ~1mb. (3)
How to "media emulate print" without Developer Toolbar (GCLI)? (20)
PPA, Snap, or Flathub release channel for Developer Edition (2)
Text writing (4)
Can't set Debugger breakpoints (2)
Request tab in Network to explore JSON payload sent (2)
Vim bindings: when editing `Esc` conflicts with shortcut for toggling the split console (1)
Flexbox Inspector - input wanted ( 2 ) (24)
Undock DevTools panes and place them side-by-side (2)
Is there a way to add develeoper tools inspector icon on status bar (1)
cookies is not visible (2)
Possible to keep the dev tools inspector panels stacked? (1)
Missing Firefox add-on debugger dialog asking to accept incoming connection (1)
Javascript's alert does not work in responsive design mode (3)
User agent switcher (10)
Network Tab: how does "Modify and Resend" feature work? (1)
Feedback about the Style Editor wanted (3)
DOM Mutation Breakpoints (3)
Set multiple "measure"'s instances (3)
Where can find place of a file on host during editing by inspect on browser mozilla? (2)
Devtools slow and occasionally unresponsive on some sites ( 2 3 ) (46)
Inspect element - add new class (4)
Would anybody else appreciate an "auto" option for Dev Tools theme? (2)
Call Firefox helper functions from JS (3)
Proposal: Add more contrast to Toolbox buttons (1)
Responsive Design Mode: New designs in the works - input wanted ( 2 ) (22)
Network shows 0 B size (2)
Inspector: "No element selected" (No CSS) (4)