SSL and certificates
Tools for SSL and TLS certificates: check a site's certificate and chain, decode what a certificate actually contains, generate a CSR or a self-signed certificate, match a private key to its certificate and convert between formats.
SSL Checker
Enter a domain to inspect its HTTPS certificate: who issued it, when it expires, whether the chain is complete and which TLS versions the server accepts.
Certificate chain fixer
Paste your certificates and get a correctly ordered chain file. Finds the missing intermediate and downloads it for you.
Let’s Encrypt troubleshooter
Find out why certbot cannot validate your domain. Checks DNS, the challenge path over HTTP and your CAA records from outside.
SSL certificate decoder
Read any X.509 certificate: expiry, SAN, issuer, key strength, chain. Explains what is wrong, not only what the fields say.
CSR generator
Create a certificate signing request and its private key in your browser. RSA or ECDSA, every domain in the SAN, no openssl needed.
Self-signed certificate generator
Make an HTTPS certificate for localhost or an internal host. Builds a local CA so the browser warning goes away for good.
Key and certificate matcher
Check whether a private key belongs to a certificate or CSR. Works with RSA and EC, encrypted keys and .pfx bundles.
Certificate format converter
Convert certificates and keys between PEM, DER, PKCS#8, PKCS#1 and PFX. Opens old Windows .pfx exports other tools reject.
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