Firefox 145 for developers
This article provides information about the changes in Firefox 145 that affect developers. Firefox 145 is the current Nightly version of Firefox and ships on November 11, 2025.
Note: The release notes for this Firefox version are still a work in progress.
Changes for web developers
Changes for add-on developers
- Cookies created with
cookies.set()are now validated, and invalid cookies are rejected. This change was implemented in Nightly only from Firefox 142. (Firefox bug 1976509)
Experimental web features
These features are shipping in Firefox 145 but are disabled by default.
To experiment with them, search for the appropriate preference on the about:config page and set it to true.
You can find more such features on the Experimental features page.