WEBPery

JPEG XL

.jxl

Royalty-free next-generation image format with outstanding compression and lossless JPEG transcoding, held back by fragmented browser support.

rasterbothTransparencyAnimation20% browser support

Origin and design intent

JPEG XL (JXL) is a next-generation image format from the Joint Photographic Experts Group — the same committee behind the original JPEG. It was standardised as ISO/IEC 18181, with the core coding system published in 2021. The format merges two research codecs: Google's PIK and Cloudinary's FUIF.

The design priorities were broad:

  • One format for every job — lossy and lossless, photographs and graphics, still and animated.
  • Lossless JPEG transcoding — recompress existing JPEG files ~20% smaller with no quality change, fully reversible.
  • Royalty-free licensing to avoid the patent friction that slows format adoption.

Compression

JPEG XL uses two internal modes. VarDCT handles lossy photographic content with a variable-block discrete cosine transform. The modular mode handles lossless and near-lossless content, including graphics and high-bit-depth images.

At equal quality, JPEG XL typically compresses better than WebP and is competitive with AVIF, particularly at high fidelity where AVIF's compression curve flattens. Its standout feature is lossless JPEG recompression: an existing JPEG becomes a JXL roughly 20% smaller, and can be restored to the byte-identical original.

Features

JPEG XL supports the full modern feature set: an alpha channel, animation, high dynamic range, up to 32-bit-per-channel precision, wide colour gamuts, and progressive decoding that renders a low-resolution preview before the full image arrives.

This makes it technically one of the most capable raster formats available — broader than WebP and matching or exceeding AVIF on bit depth and progressive rendering.

The browser support problem

JPEG XL's adoption is defined by a browser-support setback. Google added JPEG XL to Chrome behind a flag in version 109, then removed it entirely in Chrome 110 in 2023, citing insufficient ecosystem interest. Chromium-based browsers — Chrome, Edge, Opera, Brave — therefore do not support it.

Apple moved the other way: Safari 17 and iOS 17 added JPEG XL support by default in 2023. Firefox keeps it behind a configuration flag, disabled by default. The practical result is that JPEG XL renders by default only in Safari, leaving global support low and fragmented.

This is the single fact that determines where JPEG XL can be used today. For web delivery to a general audience, it cannot yet replace WebP.

Use cases

JPEG XL suits environments where you control the client or where Safari coverage is enough. It excels at lossless JPEG recompression for archival storage, high-bit-depth and HDR photography, and professional imaging workflows.

For public websites serving all browsers, WebP remains the reliable default and AVIF the aggressive-compression option. JPEG XL is a format to prepare for rather than deploy broadly.

How JPEG XL compares

Further reading

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