How to use HSTS Checker
- Paste the text you need to check into the input box.
- Set Paste the Strict-Transport-Security header so the output fits your use case.
- Watch the output update instantly while you adjust the text.
- Use Copy to keep or reuse the result.
About this tool
HSTS Checker is a static, client-side tool with no backend. HSTS Checker handles your input locally and returns the result instantly, with no sign-up.
It is designed to do one job well and stay out of your way. Your input never leaves the page, and no account or install is required.
Frequently asked questions
What does HSTS Checker do?
HSTS Checker lets you check your input right in the browser using the Paste the Strict-Transport-Security header control, with the result shown instantly and nothing uploaded.
Does HSTS Checker cost anything?
No — HSTS Checker is completely free, with no sign-up and no hidden limits.
Is my input private in HSTS Checker?
Yes — your input never leaves your device; HSTS Checker does all the work in your browser.
Does HSTS Checker work offline?
Once the page has loaded, HSTS Checker keeps working with no network connection.