Developer credentials are the secrets that let a maintainer or engineer access development systems and release software, such as passwords, API tokens, SSH keys, publish tokens, and CI secrets. In practice, they are the keys to package registries, source repositories, build pipelines, and cloud consoles.
They matter because stealing one valid credential can give an attacker the same trust as the real developer. In a supply-chain attack, that may allow malicious package uploads, tampered releases, or changes to automation that spread harmful code through legitimate channels. Defenders reduce this risk with two-factor authentication, short-lived or scoped tokens, trusted publishing with federated identity, secret scanning, and rapid revocation and rotation when a secret is exposed.