Simple Error
RESP2prefix: - · client type: Exception / Error / exception class
Simple errors use the - prefix to signal command failures. The first word in upper case is the error code; the remainder is the human-readable message. Common codes: ERR (generic), WRONGTYPE (type mismatch), NOAUTH (authentication required), NOPERM (ACL permission denied).
Details
Simple errors have the format -<CODE> <message>\r\n. The error code is the first space-separated uppercase word; it allows clients to distinguish error categories without parsing the message string.
Common error codes: ERR – generic error WRONGTYPE – operation on wrong data type (e.g., LPUSH on a string key) NOAUTH – authentication required but not provided NOPERM – ACL permission denied LOADING – server is loading the dataset from disk BUSY – server is processing a slow script BUSYKEY – key already exists (CREATE with NX)
In RESP3 the equivalent is the blob error type (!) which supports binary-safe error messages. Simple errors remain valid in both RESP2 and RESP3.
Wire encoding
-ERR wrong number of arguments for 'get' command\r\n -WRONGTYPE Operation against a key holding the wrong kind of value\r\n -NOAUTH Authentication required.\r\n
Type information
| Prefix byte | - |
| Version | RESP2 |
| Client type | Exception / Error / exception class |
| Specification | RESP3 specification (GitHub) → |