Timothy Nikkel announced on Mozilla's dev-platform list that Firefox 157 will turn JPEG XL decoding on by default on all platforms. The feature has been developed behind the image.jxl.enabled preference, currently enabled on Nightly and available via a Firefox Labs checkbox since version 152. The decoder is jxl-rs, written in Rust.

Performance concerns raised during the intent to prototype phase have been addressed. jxl-rs 0.6.0 introduced multithreaded decoding, and benchmarks show it slightly ahead of Safari's C++ libjxl on large images. JXL offers feature parity with other formats, including animation and progressive display, though HDR images display as SDR.

Safari shipped JPEG XL in version 17.0 in 2023, while Chrome keeps it behind a flag. Testing includes Web Platform Tests, gecko tests for chunked decoding, and fuzzing. Animated JXL is supported.

Sergey Davidoff raised concerns about lossless JPEG XL being 30x slower than lossless WebP, suggesting shipping only lossy JPEG XL initially. Nikkel's plan remains to enable the full format by default.