How does Redis AUTH work?

Redis AUTH provides password-based authentication. Set a password in redis.conf with requirepass yourpassword. Clients must then send AUTH yourpassword before any other command or they receive a NOAUTH error. Redis 6+ introduced ACL (Access Control Lists), which is a major upgrade: you can create multiple users (ACL SETUSER) with different passwords and fine-grained command and key permissions — e.g., a read-only user that can only run GET and HGET on keys matching cache:*. ACLs are the modern, recommended approach over the legacy single-password requirepass for any production deployment. Always use TLS (via stunnel or Redis 6's native TLS) alongside AUTH when Redis is exposed over a network.