Show Certificate information

❯ certinfo foo.crt
Subject        : CN=*.foo.balki.me
Issuer         : CN=E7,O=Let's Encrypt,C=US
Serial         : 449999999999999999999999999999999999999997
NotBefore      : 2025-08-30 10:48:18 +0000 UTC
NotAfter       : 2025-12-19 12:48:17 +0000 UTC
DNSNames       : [*.foo.balki.me]
SignatureAlgo  : ECDSA-SHA384
PublicKeyAlgo  : ECDSA

❯ certinfo --json foo.crt | jq '.[] | .Subject.CommonName'
"*.foo.balki.me"
"E7"

Use without installing

go run go.balki.me/certinfo@latest foo.crt

podman run -v $PWD:/w -w /w --rm golang go run go.balki.me/certinfo@latest foo.crt

docker run -v $PWD:/w -w /w --rm golang go run go.balki.me/certinfo@latest foo.crt

---

Prefer to use the ugly openssl CLI instead ?

openssl x509 -in foo.crt -text -noout

podman run -v $PWD:/w -w /w --rm archlinux openssl x509 -in foo.crt -text -noout