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.
Brotli in practice
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.
How it works: our server downloads the page once through a guarded fetcher that only connects to public addresses, follows a limited number of redirects and stops after a size and time limit. The HTML is then analysed in your browser as inert text – scripts on the page never run and nothing is stored.
What it cannot see: content and resources that a page adds with JavaScript after it loads, pages behind a login, and servers that block automated requests. For those, open the page in your browser, use its developer tools, or paste the page source where the tool offers a paste option.
Use the results as a starting point: fix the items marked red first, review the yellow warnings in context, and run the check again after a change. Requests are rate-limited to keep the service fair; if you check many pages in a row, wait a few minutes.
Related checks on this site cover the rest of a technical review – speed and Core Web Vitals, security headers, structured data, accessibility and SEO signals – so you can work through a whole site audit one topic at a time.
Who it is for: site owners checking their own pages, developers debugging a release, SEO and marketing teams auditing clients or competitors, and students learning how the web works. No account or installation is needed, and the results are plain text and tables you can copy into a report or ticket.