Brotli Compression Checker

What this tool checks

This checker requests your URL with compression enabled and inspects the response headers. If the response includes Content-Encoding: br, Brotli is active. If you see gzip, the server fell back to gzip.

Why Brotli matters

Brotli usually delivers smaller payloads than gzip for text assets, which means faster HTTPS delivery and better Core Web Vitals. It is especially effective for HTML, CSS, JS, JSON, and SVG.

How to confirm Brotli

• Content-Encoding: br confirms Brotli is enabled.
• Vary: Accept-Encoding ensures caches store the right variant.
• Content-Type: Brotli should target text-based responses.
• Cache-Control: Strong caching maximizes the benefit of Brotli.

Common reasons you may not see Brotli

• Brotli is enabled only on HTTPS, and you are testing HTTP.
• The CDN or server is configured to use gzip as a fallback.
• The response is already small or not a compressible MIME type.
• The origin sends an already-compressed response.

Best practices

• Enable Brotli at the CDN edge and keep gzip as a fallback.
• Precompress large static assets and serve .br files when supported.
• Ensure text assets have correct MIME types.
• Avoid compressing already-compressed binary formats.

Quick checklist

1. Test over HTTPS with Accept-Encoding: br.
2. Confirm Content-Encoding: br in the response.
3. Check Vary: Accept-Encoding for cache safety.
4. Make sure the asset is text-based and cacheable.