Download Firefox Developer Edition 149.0b4

Get the latest features, fast performance, and the development tools!

Updated: March 06, 2026

Size: 161 MB

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161 MB · March 06, 2026

Firefox%20149.0b4.dmg

Previous versions More »

149.0b5 March 08, 2026 160 MB 149.0b4 March 06, 2026 161 MB 149.0b3 March 04, 2026 160 MB 149.0b2 March 01, 2026 160 MB 148.0b15 February 15, 2026 158 MB 148.0b14 February 13, 2026 158 MB