SSL Certificate Checker
Paste a PEM certificate to decode subject, issuer, validity dates, SANs, key and SHA-256 fingerprint — and check whether it covers a host. It runs entirely in your browser — no signup, no installation, and nothing you paste or drop leaves your device.
What the SSL Certificate Checker shows you
The SSL Certificate Checker reads any PEM certificate and shows who issued it, who it was issued to, when it becomes valid, when it expires and how many days are left. Paste the certificate from your server, hosting panel or .crt file, type the hostname you want to verify, and the tool checks the Subject Alternative Names against real browser wildcard rules, together with the public key, the signature algorithm, the serial number and the SHA-256 fingerprint. Everything is parsed in your browser, so the certificate is never uploaded and internal or staging certificates stay private. Use it before a renewal to see the remaining days at a glance, or after a deployment to confirm that the certificate installed on the server is really the one you ordered.
Was der SSL-Zertifikat-Prüfer anzeigt
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What is SSL Certificate Checker?
SSL Certificate Checker is a free online developer tool built for developers debugging payloads, configs and code. Paste a PEM certificate to decode subject, issuer, validity dates, SANs, key and SHA-256 fingerprint — and check whether it covers a host In practice you paste the PEM certificate, read subject, issuer, validity dates and SANs, and then check the SHA-256 fingerprint and whether the certificate covers a host.
Your code, tokens and payloads never leave the browser, which matters when you are debugging something under NDA or handling production data.
How to use SSL Certificate Checker
- Paste the PEM certificate.
- Read subject, issuer, validity dates and SANs.
- Check the SHA-256 fingerprint and whether the certificate covers a host.
SSL Certificate Checker FAQ
Is SSL Certificate Checker free to use?
Yes. SSL Certificate Checker is completely free and needs no account, no trial and no payment details. Every feature on the page is available without limits.
Is my data uploaded anywhere?
No. SSL Certificate Checker runs entirely in your browser, so the text, file or number you enter never leaves your device.
Does SSL Certificate Checker work on a phone or tablet?
Yes. It works in any modern browser on desktop, tablet and phone. There is no app to install and no account to create.
How do I use SSL Certificate Checker?
Paste the PEM certificate. Read subject, issuer, validity dates and SANs. Check the SHA-256 fingerprint and whether the certificate covers a host.