Free tools
Quick checks for websites and APIs
One-off diagnostics that run from our servers in Germany. No account needed. When you want the same check on a schedule, Asniher monitors it for you.
SSL certificate checker
See issuer, expiry date, days remaining, covered names and TLS protocol for any domain.
Is it down?
Check whether a website responds right now, with status code and response time from Germany.
HTTP header checker
List response headers and grade six security headers, from Strict-Transport-Security to Permissions-Policy.
Stop checking by hand
Monitor websites, APIs, certificates and cron jobs continuously. Free plan includes 5 monitors.