How to use Certificate Checker Online
- Drop your text into the field at the top of Certificate Checker Online.
- Use the Paste a PEM certificate (BEGIN/END lines) setting to control the result.
- The result is computed live in your browser as you edit the input.
- Finish by choosing Copy to take the output with you.
About this tool
Certificate Checker Online runs entirely in your browser. Certificate Checker Online decodes a pasted PEM certificate in your browser to read its subject, issuer, validity and serial.
Export a site certificate from the browser padlock as PEM to inspect it here. No data is sent anywhere, so it stays fast and private by default.
Frequently asked questions
What is Certificate Checker Online for?
Certificate Checker Online lets you check your input right in the browser using the Paste a PEM certificate (BEGIN/END lines) control, with the result shown instantly and nothing uploaded.
Is Certificate Checker Online free to use?
Yes — Certificate Checker Online is completely free, with no usage limits.
Is my input private in Certificate Checker Online?
Yes — your input never leaves your device; Certificate Checker Online does all the work in your browser.
How do I inspect a live site's certificate with Certificate Checker Online?
Export the certificate from your browser's padlock as PEM and paste it into Certificate Checker Online; it decodes the fields locally.
Does Certificate Checker Online work offline?
Once the page has loaded, Certificate Checker Online keeps working with no network connection.