Download Firefox Developer Edition 143.0b4

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

Updated: August 27, 2025

Size: 150 MB

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150 MB · August 27, 2025

Firefox%20143.0b4.dmg

Previous versions More »

143.0b9 September 07, 2025 149 MB 143.0b8 September 05, 2025 149 MB 143.0b7 September 03, 2025 149 MB 143.0b6 August 31, 2025 150 MB 143.0b5 August 29, 2025 150 MB 143.0b4 August 27, 2025 150 MB