Server Response Headers: What to Look For
Response headers are service information that the server sends before the page itself: response code, content type, caching rules, compression, protection. They reveal what is not visible in the page code. You can check them using header checking.
What to Look For
| Header | What It Indicates |
|---|---|
| Response Code | 200 for a working page; 3xx, 4xx, and 5xx require analysis |
| Content-Type and Encoding | Incorrect encoding breaks text display |
| Cache-Control and ETag | How the page is cached; affects the speed of repeat visits |
| Content-Encoding | Is compression enabled — on text pages this is a significant saving |
| X-Robots-Tag | Hidden indexing prohibition: there is no meta tag on the page, but there is a prohibition |
| Security Headers | Protection against embedding and code injection — analysis |
| Server and X-Powered-By | Software version: it's better to hide it from vulnerability scanners |
X-Robots-Tag header: the page code is clean, but the page is not in the index. If indexing is not happening for no visible reason, check the headers — see indexing check.How to View Headers Yourself
An instrument is more convenient, but the same can be seen in the browser: open the developer tools, the network requests tab, reload the page, and select the first request — there you will find the request and response headers. This same place shows the actual redirect chain and what response the browser received before all scripts.
When This Is Needed
- The page is not indexed, although it looks normal.
- The site is slow on fast hosting — check compression and caching.
- After migration: response codes and redirects are visible immediately.
- When setting up protection — ensure that the headers are indeed being sent.
Headers and Speed
Two lines in the response solve more than it seems: proper caching of static files saves repeat visitors from loading the same files, and compression reduces text responses several times. Both settings are done once on the server side and apply to the entire site — this is the most cost-effective type of optimization in terms of effort and result.
Nearby
Redirect Chains, certificate, and a complete technical analysis of the site in SEO Audit.