mod_deflate compression on or off for your account. When on, Apache gzips text-based responses (HTML, CSS, JS, JSON) before sending them, which usually shaves 60–70% off transfer size.
The three options
| Option | What it does |
|---|---|
| Disabled | Apache sends responses uncompressed. Most content is bigger over the wire. |
| Compress all content | Apache gzips everything text-shaped that goes out. Best default for almost every site. |
| Compress the specified MIME types | Apache only gzips the listed MIME types. Useful if you have a specific file type you don’t want compressed. |
When the default is correct
If you’re a typical WordPress, Joomla, Laravel, or static-site account: Compress all content is what you want, and it’s likely already set. Don’t toggle.When to consider changing it
- You’re running AccelerateWP. AccelerateWP handles compression itself. Leaving Apache compression on is fine but redundant. Don’t disable Apache compression to “let AccelerateWP do it” without testing. Many AccelerateWP setups still rely on Apache as a fallback.
- Your CDN compresses upstream. Cloudflare, BunnyCDN, etc., compress on their edge. Some hosts disable origin compression to reduce CPU. Test before changing. If a connection bypasses the CDN, the visitor gets the uncompressed origin response.
- You’re serving large pre-compressed assets. If your build pipeline outputs
.js.gzfiles alongside.js, double-compression by Apache wastes CPU. The “compress specified MIME types” option lets you excludeapplication/octet-streametc.
When to leave it alone
- You don’t know what gzip is. The default is right for you.
- The site works. Don’t tinker.
- Your last performance test came back fine.
Compression is largely commodity now. The bigger speed wins for most sites are caching, CDN, and image optimization, not toggling this setting.
Common issues
Pages return as garbled text or download as binary
Pages return as garbled text or download as binary
Either compression is being applied to a content type that doesn’t survive it, or two layers are double-compressing. Set Optimize Website to Disabled as a quick test. If pages render correctly, find which other layer is also compressing (CDN, caching plugin, custom
.htaccess rule) and pick one.My PageSpeed score went down after enabling AccelerateWP
My PageSpeed score went down after enabling AccelerateWP
AccelerateWP enables gzip in its own way. If both are enabled, the response can be doubly compressed in some setups. Try disabling Optimize Website and see if PageSpeed recovers. See the AccelerateWP overview for context.
Apache compression doesn't seem to be working at all
Apache compression doesn't seem to be working at all
Check the response headers in your browser DevTools.
Content-Encoding: gzip means it’s working. If absent, either compression is off, the response is too small to compress (Apache skips bodies under ~1 KB), or the request didn’t ask for it (clients send Accept-Encoding: gzip to request it).