WebP for TYPO3

Images make up 50 to 70 percent of page weight, and WebP cuts them by a third

The average TYPO3 website loads 2 to 5 MB of image data per page. That is the largest single factor in load time, and therefore in the Google PageSpeed score. WebP is an image format developed by Google that, at comparable quality, is 25 to 35 percent smaller than JPEG and up to 80 percent smaller than PNG. The TYPO3 WebP extension converts existing JPG and PNG images to WebP automatically, without editors having to change how they work. Images are uploaded to the FAL backend as usual; the extension creates the WebP variant in the background and serves it to browsers that support the format. All modern browsers have supported WebP since 2020: Chrome, Firefox, Safari and Edge.

For websites that are already optimized for PageSpeed, WebP conversion is often the final step that lifts the score from 85 to 95 or higher.

Image-heavy websites, e-commerce and mobile-first projects gain the most

The most common scenario is image-heavy corporate websites. A real estate portal shows 15 to 25 photos per property. With 500 properties, that is 10,000 images. Without WebP, an image weighs 250 KB on average (JPEG); with WebP, 170 KB. On a listing page with 20 properties and one cover image each, WebP saves 1.6 MB per page view. At 50,000 page views a month, that is 80 GB less traffic, which has a direct effect on hosting costs.

A second scenario is e-commerce integrations. A shop system shows product images in several sizes: thumbnail, listing view, detail view and zoom. A WebP variant is generated for each size. For a shop with 2,000 products and five image variants each, that produces 10,000 WebP files that measurably speed up page rendering in the listing view.

Third scenario: mobile-first websites for audiences with poor connectivity. An NGO portal used in regions with 3G networks benefits disproportionately from smaller image files. The difference between a load time of 5 seconds and one of 15 seconds decides whether the visitor sees the page or gives up.

Conversion happens inside the TYPO3 image processing pipeline

The extension hooks into TYPO3’s image processing pipeline. Whenever TYPO3 processes an image (resize, crop), the extension also creates a WebP variant in the same directory. Delivery works through content negotiation: the server checks the browser’s Accept header. If the browser accepts “image/webp”, it receives the WebP file; otherwise, it gets the original JPEG or PNG.

Technically, there are two ways to implement this. The first uses rewrite rules in Apache (mod_rewrite) or nginx that redirect image requests to the WebP variant if one exists. The second uses a TYPO3 middleware that manipulates the response header. The rewrite variant performs better, because it runs before PHP.

The conversion itself runs through libwebp (the cwebp command-line tool), ImageMagick with WebP support, or the PHP GD extension (if compiled with WebP support). Quality is configurable: the default is 80 (out of 100), a good compromise between file size and visual quality. For photographic content, we recommend 82 to 85; for screenshots and illustrations, 75 to 78.

For even better compression, newer versions of the extension support the AVIF format, which saves another 20 to 30 percent compared with WebP. AVIF is supported in Chrome and Firefox, and in Safari since version 16.

Most problems come down to missing server libraries and CDN configuration

The most common problem is a missing cwebp binary on the server. Shared hosting environments often do not have libwebp installed, and the host does not allow binaries to be installed. The fix: use PHP GD with WebP support (available in most PHP versions from 7.1 onward) or choose a hosting provider that supplies cwebp. On managed servers and in Docker containers, installation is trivial: apt-get install webp.

Second problem: CDN configuration. If a CDN (Cloudflare, Fastly, AWS CloudFront) sits in front of the website, it has to handle WebP correctly. There are two approaches. Either the CDN understands content negotiation and caches WebP and JPEG as separate variants (Vary: Accept), or the TYPO3 website serves WebP URLs directly (without content negotiation) and the CDN caches only one version. Cloudflare offers automatic WebP conversion through Polish, which makes the TYPO3 extension partly redundant.

Third issue: quality control. If the quality setting is too low (below 70), artifacts become visible, especially in color gradients and fine textures. After configuration, run an A/B comparison (original vs. WebP) to make sure the quality is acceptable for the use case.

TYPO3 v12 and v13 are supported, and the extension is one of the most stable in the ecosystem

The WebP extension is one of the most frequently installed performance extensions in the TYPO3 ecosystem. It is actively maintained and compatible with TYPO3 v12 and v13. Because its core functionality (image processing hook, file conversion) relies on stable TYPO3 APIs, breaking changes during upgrades are rare. Gosign configures WebP as standard in every new TYPO3 project and additionally enables AVIF for maximum compression where it is available.