About the GZIP/Brotli & Browser Cache Checker
Compression and caching are two of the simplest speed wins. This checker fetches a public page and its CSS, JavaScript and image files from our server and reports the Content-Encoding (gzip, Brotli or none) and the caching headers for each, including Cache-Control max-age and ETag.
Text files such as HTML, CSS and JS should be compressed; Brotli usually produces smaller files than gzip. Images are already compressed formats and do not benefit much from gzip. Static files with versioned or hashed names can be cached for a long time, often a year, so repeat visitors do not download them again, while HTML usually needs a short cache or revalidation so updates appear quickly. Most fixes are a setting in your server, CDN or caching plugin.
How to use it
- Enter a public page URL.
- Check the compression status of the HTML and each asset.
- Review Cache-Control and ETag headers for static files.
- Enable compression and longer caching in your server or CDN settings.
Frequently asked questions
Is Brotli better than gzip?
Brotli typically compresses text files smaller than gzip at similar speed and is supported by all modern browsers over HTTPS. Servers usually offer Brotli to browsers that accept it and fall back to gzip. Either is far better than no compression.
How long should static files be cached?
Files with a version or hash in the name, which change name when updated, can safely use a long max-age such as one year, often with immutable. Files that keep the same name when changed need a shorter cache or revalidation with ETag so visitors get updates.
Why are my images not compressed?
JPG, PNG, WebP and AVIF are already compressed formats, so gzip or Brotli adds little and servers usually skip them. Reduce image size by resizing, using better compression settings or converting to modern formats instead. SVG files are the exception, since they are text and do benefit from gzip or Brotli.