Performance Tools

Content Encoding Checker

Check which content encoding (gzip, br, deflate, or identity) a website uses.

Not sure what to enter? Try an example: wikipedia.org

Free & instant No signup How to use FAQ

Enter a domain to check which content encoding it uses.

What is Content-Encoding?

The Content-Encoding response header says how the body was compressed: br (Brotli), gzip, deflate, or identity (not compressed). This checker requests the page the way a browser does and reports the encoding the server chose.

How to check a website's content encoding

Enter the domain in the box above.
Click Check Encoding.
br or gzip means text is compressed; identity or nothing means it is not.
Enable compression for text responses in your server or CDN - images and videos are already compressed.

Related checks

To check GZIP specifically, use the GZIP Compression Checker.
To check Brotli, use the Brotli Compression Checker.

Compress text files such as HTML, CSS, JavaScript and SVG, but not images or videos that are already compressed. JustChecker monitors response times so a misconfigured server shows up quickly.

Frequently Asked Questions

It means no compression is being applied at all - the response is sent exactly as-is, which is the least efficient option for text-based content and worth investigating if seen on a page that should be compressed.

Those tools check specifically for one compression method each; this tool reports whichever encoding is actually being used right now (gzip, br, deflate, or none), giving a single, direct answer rather than checking each possibility separately.

Deflate is an older, less commonly used compression format with less consistent client support than GZIP - it's relatively rare to see intentionally chosen over GZIP or Brotli on a modern, well-configured server.

Yes - a server might compress HTML/CSS/JS responses while correctly leaving already-compressed formats like JPEG images uncompressed, since compressing an already-compressed file provides negligible benefit and wastes CPU time.

The browser sends an Accept-Encoding header listing what it supports; the server then chooses the best mutually-supported option to actually use - it's a negotiation, not a purely server-side or purely client-side decision.

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