In July 2016, Apple added WebP support to early beta versions of macOS Sierra and iOS 10, but support was later removed in the GM seed versions of iOS 10 and macOS Sierra released in September 2016. According to Google's measurements in November 2011, a conversion from PNG to WebP resulted in a 45% reduction in file size when starting with PNGs found on the web, and a 28% reduction compared to PNGs that are recompressed with pngcrush and PNGOUT. On 18 November 2011, Google announced a new lossless compression mode, and support for transparency ( alpha channel) in both lossless and lossy modes support was enabled by default in libwebp 0.2.0 (16 August 2012). Older animated GIF files can be converted to animated WebP. On 3 October 2011, Google added an 'Extended File Format' allowing WebP support for animation, ICC profile, XMP and Exif metadata, and tiling (compositing very large images from maximum 16384×16384 tiles).

WebP-related software is released under a BSD free software license. As a derivative of the VP8 video format, it is a sister project to the WebM multimedia container format.

It was based on technology that Google acquired with the purchase of On2 Technologies.

WebP was first announced by Google on 30 September in 2010 as a new open format for lossy compressed true-color graphics on the web, producing files that were smaller than JPEG files for comparable image quality.