How to use Mail SSL Test
- Give Mail SSL Test a PEM certificate to work from.
- Press Parse certificate to run it locally in your browser.
- Read the subject, issuer, validity dates and expiry that Mail SSL Test lays out for you.
About this tool
Mail SSL Test is a static, client-side tool with no backend. Paste a PEM certificate and Mail SSL Test parses the X.509 fields entirely on your device.
To check a live site, export its certificate from the browser padlock as PEM and paste it here. Nothing you enter is uploaded, and it keeps working offline once the page has loaded.
Frequently asked questions
What is Mail SSL Test for?
Use Mail SSL Test to check your input without installing anything; everything happens client-side.
Is Mail SSL Test free to use?
Yes — Mail SSL Test is completely free, with no usage limits.
Where is my data processed by Mail SSL Test?
Entirely in your browser — Mail SSL Test keeps your data on your own machine and sends nothing anywhere.
How do I inspect a live site's certificate in Mail SSL Test?
Export the certificate from your browser's padlock as PEM and paste it into Mail SSL Test; it decodes the ASN.1/DER fields entirely on your device.
Does Mail SSL Test work offline?
Once the page has loaded, Mail SSL Test keeps working with no network connection.