HTTP Header Checker
View every HTTP response header a URL returns, with explanations for the security-relevant ones.
About HTTP Header Checker
Response headers control caching, security, tracking and how a browser trusts your site — but most are invisible unless you crack open devtools. This checker lists every header your server returns, in the order it returns them, and calls out the security-relevant ones with plain-English guidance on what each does.
What this tool checks
HTTP Header Checker focuses on the following signals from your site's live response:
headersmodule in the full audit
Why it matters
Signals covered by HTTP Header Checker are the ones attackers, browsers, and search engines look at first. A weak result here means real users are exposed — via downgrade attacks, broken trust warnings, indexing problems, or leaked data — long before anything obvious breaks. Fixing them is usually a config change, not a rewrite, and the impact is immediate.
How to interpret your result
- Pass — the signal meets modern best practice. Keep it monitored; regressions happen after deploys.
- Warn — functional but weaker than recommended. Usually a quick header, DNS, or config tweak away from a full pass.
- Fail — a real risk to users or search visibility. Follow the recommendation shown next to the finding — it's copy-pasteable.
Best practices
- • Re-run after every deploy — configuration drift is the #1 cause of regressions.
- • Compare against a competitor's report to spot easy wins.
- • Wire the public API into CI to gate merges on the score.
- • Fix warns before failures — they're the cheapest to close and pay off compounding gains.
Frequently asked questions
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