Website Brotli Checker
Find out whether a site uses Brotli, the compression format that makes text files smaller than gzip. The checker requests the page with Accept-Encoding: br and reads the Content-Encoding the server returns and the bytes transferred, compares them with gzip and uncompressed sizes, and checks which of the page’s CSS and JavaScript files are served with Brotli.
- Encrypted connection
- No sign-up
- Free to use
How to use Website Brotli Checker
- Enter the page address.
- Click “Check Brotli”.
- See whether Brotli is on and how much smaller it is.
- Check the asset list.
Website Brotli Checker features
Real request
Accept-Encoding: br.
Comparison
Brotli vs gzip vs none.
Assets
CSS and JavaScript.
Measured, not guessed
Real transfer sizes from our server.
Safe fetching
Public addresses only, with size and time limits.
Server shown
Which software answered.
When to use Website Brotli Checker
- Before and after enabling Brotli.
- Choosing a CDN.
- Performance audits.
- Checking static file hosting.
Website Brotli Checker FAQ
Why does the server choose the encoding?
Browsers say which encodings they accept; the server picks one. Checking each encoding separately shows what it supports.
Should images be compressed with gzip?
No – JPEG, PNG, WebP and video are already compressed; gzip only helps text files.
Do all browsers support Brotli?
All current browsers do, over HTTPS.
Why is the HTML not Brotli but the assets are?
Assets often come from a CDN with Brotli while the page comes from the origin server without it.
Does Brotli work over plain http?
Browsers only advertise Brotli on HTTPS connections, so a site served over http will receive gzip at best.
Which Brotli level should I use?
Level 11 for static files compressed in advance during a build, and a lower level such as 4–6 for dynamic pages compressed on the fly.
Do all browsers support Brotli?
All current browsers support it over HTTPS. Keep gzip enabled for older clients and tools that do not ask for Brotli.
Brotli on your server
Brotli was designed for the web and compresses HTML, CSS and JavaScript better than gzip at similar speed. Static files can be pre-compressed at the highest level for even smaller sizes.
Keep gzip enabled as a fallback for clients that do not support Brotli.
Brotli is only used when the browser asks for it (Accept-Encoding: br) and the server supports it, which in practice means HTTPS. The checker sends that request and reads the Content-Encoding returned, then compares the transferred size with gzip and with no compression.
If the result shows gzip instead of br, the server or CDN does not have Brotli enabled. Cloudflare and most CDNs offer it as a setting; on your own server it needs the Brotli module for nginx or mod_brotli for Apache. Each CSS and JavaScript file is checked too, because assets are often served by a different system than the page.
For static files, pre-compress them at Brotli level 11 during the build and let the server send the .br file directly. Dynamic HTML is usually compressed at a lower level on the fly, which is faster while still beating gzip.
If you use a CDN, Brotli is often available as a single switch in its settings, and the CDN compresses files at the edge even if your own server only supports gzip. If you host yourself, check that your server software includes the Brotli module before enabling it, and keep gzip as a fallback.