Firefox Local Mode for Web Developers
3 hours ago
- Local Mode allows loading local files via custom https:// URLs in Firefox.
- It eliminates the need to run a local HTTP server for testing web pages.
- It enables testing Web APIs, including those restricted to Secure Contexts.
- Each mapping provides a distinct origin (domain) for dedicated storage/cookies per project.
- Mappings are only accessible from Firefox and are not exposed to other programs or malicious software.
- Mappings are only functional when DevTools are opened.
- The feature is available starting in Firefox 153 and is configured in the DevTools Options panel.
- Each mapping defines an origin (custom https URL) and a local folder path.
- Loading a file:// URL with DevTools open shows a notification with actions to add the mapping to settings or try a transient mapping.
- Mappings can also be managed via about:config using three preferences per mapping: origin, path, and disabled.