10SoftwareFirefox extension · Manifest V3 · JavaScript
CalmWeb
A Firefox extension that reduces motion, pauses autoplay, freezes busy GIFs, dims harsh colour and flashing brightness, and keeps loud media in check — with adjustable safety controls and per-site overrides.
Open source on GitHub
Fewer reasons to look away
CalmWeb targets the ingredients that make the web hard to sit with: constant motion, autoplay, aggressive colour, flashing brightness and startling volume. Each one can be dialled down independently or switched off.
An audio limiter caps media volume to a chosen maximum, flash dimming rate-limits flicker and lowers flashing brightness, and page dimming can drop overall brightness for late-night reading. A per-site toggle plus a global master switch keeps control where it is most useful.
Safety controls with nothing underneath
The extension requests only storage (to remember settings) and activeTab (to act on the tab in view). It declares data_collection_permissions: none, collects nothing and sends nothing anywhere.
Everything runs locally in the browser; the code is open so the safety story is readable, not just claimed.
What makes it technically interesting
- Stops CSS animations and transitions, and pauses autoplaying video and audio
- Freezes animated GIFs, plus optional desaturation (0–100%) and light/dark/inverted theme modes
- Audio limiter caps media volume to a chosen maximum; flash dimming rate-limits flicker and lowers flashing brightness
- Page dimming lowers overall brightness, with enable/disable per site and a global master switch
- Collects nothing and sends nothing anywhere: only storage and activeTab permissions (manifest declares data_collection_permissions: none)