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TLS certificate inspector

Decode a supplied PEM certificate to inspect its subject, issuer, validity period, key algorithm and SHA-256 fingerprint.

On your device · No account
Privacy details

TLS certificate inspector processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

Copy link includes the inputs you choose to share in the address. Anyone with that link can reopen them. Files and generated results are excluded. Password and key tools share settings only.

Options and local file

This parses one certificate on your device. It does not connect to a hostname, establish trust, verify a chain, check revocation or prove that a server is using the certificate. Never paste a private key.

Your result

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.
Links include your inputs and settings. Anyone with the link can see them, so leave out private text. Files and generated results are left out; random draws run again.
Keyboard shortcuts
Updated 
Using TLS certificate inspector
Decode a supplied PEM certificate to inspect its subject, issuer, validity period, key algorithm and SHA-256 fingerprint.
Next: Hash generator checker
Next: Base64 encoder and decoder
A worked example
The synthetic example certificate has subject CN=example.invalid, serial 7b and a validity period from 1 January 2026 to 1 January 2027.
Before you use the result
This parses one certificate on your device. It does not connect to a hostname, establish trust, verify a chain, check revocation or prove that a server is using the certificate. Never paste a private key.
Cite this page
ToolOctopus. “TLS certificate inspector.” Updated 2026-09-29. https://tooloctopus.com/tls-certificate-inspector.
Add an access date if your instructions require one.
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