How to use Smtp SSL Test
- Add a PEM certificate to Smtp SSL Test to get started.
- Hit Parse certificate and Smtp SSL Test computes the result client-side.
- Use the subject, issuer, validity dates and expiry Smtp SSL Test produces — nothing was uploaded.
About this tool
Smtp SSL Test is a static, client-side tool with no backend. Paste a PEM certificate and Smtp 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. It behaves the same on desktop and mobile, with nothing stored remotely.
Frequently asked questions
What is Smtp SSL Test for?
Smtp SSL Test runs entirely on your device: add your input, and it checks it locally in real time.
Does Smtp SSL Test cost anything?
No — Smtp SSL Test is completely free, with no sign-up and no hidden limits.
Is my input private in Smtp SSL Test?
Yes — your input never leaves your device; Smtp SSL Test does all the work in your browser.
How do I inspect a live site's certificate in Smtp SSL Test?
Export the certificate from your browser's padlock as PEM and paste it into Smtp SSL Test; it decodes the ASN.1/DER fields entirely on your device.
Does Smtp SSL Test work on mobile?
Yes — Smtp SSL Test is just a web page and runs on any modern browser, including phones and tablets.