SISMEMBER - Upstash Documentation

Use SISMEMBER to check whether a value is a member of a set.

The reply is 1 when it is and 0 when it is not or the key does not exist. The check is a constant-time lookup and transfers nothing but the answer, which is why sets are the right structure for membership questions such as permission or blocklist checks. Use SMISMEMBER to test several values in one call.

Syntax#

SISMEMBER <key> <member>

Arguments#

Argument	Required	Repeatable	Description
`<key>`	Yes	No	Redis key targeted by the command.
`<member>`	Yes	No	Member name.

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.

Protocol	Reply
RESP2	Integer: `1` if the member is in the set, `0` otherwise
RESP3	Integer: `1` if the member is in the set, `0` otherwise

Note

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.

Redis CLI

SISMEMBER my-key member

@upstash/redis

import { Redis } from "@upstash/redis";const redis = Redis.fromEnv();await redis.sadd("set", "a", "b", "c");const isMember =  await redis.sismember("set", "a");console.log(isMember); // 1

upstash_redis

from upstash_redis import Redisredis = Redis.from_env()result = redis.sismember("my-key", "member")print(result)

ioredis

import Redis from "ioredis";const redis = new Redis(process.env.REDIS_URL!);const result = await redis.sismember("my-key", "member");console.log(result);

node-redis

import { createClient } from "redis";const client = await createClient({ url: process.env.REDIS_URL })  .on("error", console.error)  .connect();const result = await client.sIsMember("my-key", "member");console.log(result);

redis-py

import osimport redisclient = redis.from_url(os.environ["REDIS_URL"])result = client.sismember("my-key", "member")print(result)

go-redis

package mainimport (    "context"    "fmt"    "os"    "github.com/redis/go-redis/v9")func main() {    opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))    if err != nil {        panic(err)    }    client := redis.NewClient(opts)    result, err := client.SIsMember(context.Background(), "my-key", "member").Result()    if err != nil {        panic(err)    }    fmt.Println(result)}

jedis

import java.net.URI;import redis.clients.jedis.Jedis;try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {  Object result = jedis.sismember("my-key", "member");  System.out.println(result);}

redis-rs

use redis::TypedCommands;fn main() -> redis::RedisResult<()> {    let url = std::env::var("REDIS_URL").expect("REDIS_URL is not set");    let client = redis::Client::open(url)?;    let mut connection = client.get_connection()?;    let result = connection.sismember("my-key", "member")?;    println!("{result:?}");    Ok(())}