How to use Online SSL Checker
- Add a PEM certificate to Online SSL Checker to get started.
- Press Parse certificate to run it locally in your browser.
- Review the subject, issuer, validity dates and expiry shown below.
About this tool
Online SSL Checker is a static, client-side tool with no backend. Online SSL Checker decodes a pasted PEM certificate by walking its ASN.1/DER structure locally to read subject, issuer, validity window and serial.
To check a live site, export its certificate from the browser padlock as PEM and paste it here. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
How do I use Online SSL Checker?
Online SSL Checker runs entirely on your device: add your input, and it checks it locally in real time.
Does Online SSL Checker cost anything?
No — Online SSL Checker is completely free, with no sign-up and no hidden limits.
Where is my data processed by Online SSL Checker?
Entirely in your browser — Online SSL Checker keeps your data on your own machine and sends nothing anywhere.
How do I inspect a live site's certificate in Online SSL Checker?
Export the certificate from your browser's padlock as PEM and paste it into Online SSL Checker; it decodes the ASN.1/DER fields entirely on your device.
Does Online SSL Checker work offline?
Once the page has loaded, Online SSL Checker keeps working with no network connection.