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Use LPUSHX to add elements to the head of a list only when the list already exists. Nothing happens and the reply is 0 when the key does not exist, and no key is created. This is the difference from LPUSH, and it is what you want when a list should only be fed while a consumer is holding it open, so that stale producers do not resurrect a queue that was already drained and deleted.

Syntax

Arguments

Response

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.
Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.

Examples

TCP examples use the TLS REDIS_URL from the Upstash console. REST examples use UPSTASH_REDIS_REST_URL and UPSTASH_REDIS_REST_TOKEN.

Related topics

LPUSHXOverview