Passwordless authentication is a login approach that avoids static passwords and uses stronger proof of identity instead, such as cryptographic keys, device-based trust, one-time approvals, or federated identity from a trusted provider. For human users it often appears as passkeys or single sign-on; for service accounts it may use key-pair authentication or workload identity federation.
It matters because passwords are easy to steal, reuse, copy into scripts, and leave behind in automation. Attackers often target those shared secrets through phishing, credential theft, or exposed configuration files. Passwordless methods reduce that risk by replacing long-lived secrets with short-lived tokens or private keys that are harder to reuse. In defense, they also force teams to map ownership, review access, and remove stale integrations instead of preserving hidden password-based trust.