Keycheck by the Director
Paste a public key and get an immediate, clear answer on whether it is well-formed. No key data is stored or leaves your browser except for the optional lookup below.
Supported formats: OpenSSH (ssh-ed25519, ssh-rsa, ecdsa-sha2-*, ssh-dss), PEM PUBLIC KEY blocks, and PGP PUBLIC KEY BLOCKs.
Third-party lookup: Enabled — well-formed OpenSSH keys are checked against the configured account.