Free JPEG XL converter

Convert PNG, JPG, GIF and video to JPEG XL (JXL), free. Files are made on your device, offline; nothing is uploaded. Choose the quality: Lossless, High or Medium. Under Lossless a JPEG converts exactly: smaller, and the original restores byte for byte.

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How to convert PNG or JPG to JPEG XL

  1. Choose or drop pictures: JPG, PNG, WebP, AVIF or any picture your browser opens.
  2. Choose the quality: Lossless, High or Medium. Effort keeps the picture: more effort makes a smaller file and takes longer. Under Lossless a JPEG converts exactly.
  3. Download each .jxl file, or all of them as one zip.

How to convert a video to animated JPEG XL

  1. Choose or drop an MP4, WebM or MOV.
  2. The first time, download JPEG XL complete: free, once, then offline.
  3. Up to 30 frames a second, without sound. A long or large video is scaled down or cut, and its row says so.
  4. Download the .jxl file.

How to convert a GIF to animated JXL

  1. Choose or drop an animated GIF, APNG or animated WebP.
  2. The first time, download JPEG XL complete: free, once, then offline.
  3. Choose the quality: Lossless, or High or Medium for a smaller file. Frame timing is kept.
  4. Download the .jxl file.

Questions

Is it free?

Yes. Rapier is free and open source, with no account, ads or tracking.

Is my picture uploaded?

No. Files are converted on your device.

Does it work offline?

Yes. The encoder is inside Rapier. Videos and animations need JPEG XL complete, a one-time download; after that they convert offline too.

Is JPEG XL lossless?

Lossless is. High and Medium are lossy and much smaller. A JPEG converted under Lossless restores byte for byte.

How much smaller is JPEG XL?

An exact JPEG: usually 10 to 20% smaller. A 710 KB PNG painting: 428 KB lossless, 73 KB at High, 35 KB at Medium.

What does it keep?

Transparency, 16-bit PNG (Lossless), color profiles such as Display P3 and Adobe RGB, and HDR PNGs (PQ or HLG). Video sound is dropped.

How many pictures can I convert?

Any number. Rapier converts a few at a time; Cancel stops it. If the device runs out of memory, finished files are kept.

Which browsers open JPEG XL?

Chrome 155, Firefox 158 and Safari 17 and later. Safari does not play animated JPEG XL. Any browser can make the files here.

How it works

The JPEG XL encoder is part of Rapier, which is one offline HTML file. Your browser reads each picture, or plays each video frame by frame, and the encoder writes the JPEG XL file on your device. Nothing is uploaded. A JPEG is carried into JPEG XL without decoding it, then restored and checked against the original before you download.

Why JPEG XL

In Lossless mode a JPEG converts to a smaller file and restores the exact original. Other pictures come out smaller at the same quality. JPEG XL also holds transparency, high dynamic range and animation.

Use rapier-jxl in your site or app

rapier-jxl is the JPEG XL encoder inside Rapier: pure JavaScript with optional WebAssembly, MIT licensed, no dependencies. It encodes lossless and lossy pictures and animations, carries a JPEG exactly, and keeps alpha and HDR. The still encoder is about 86 KB gzipped; the complete one, with animation and the rest of the format, about 153 KB. Run npm install rapier-jxl, then import {toJXL} from rapier-jxl/image: toJXL(file, {worker}) returns a JPEG XL Blob.

rapier-jxl on GitHub · rapier-jxl on npm