PUBSUB - Upstash Documentation

Use PUBSUB to inspect the state of the pub/sub system without subscribing to anything.

CHANNELS lists the channels that currently have at least one subscriber, optionally filtered by a glob-style pattern. NUMSUB reports the subscriber count for each channel you name, and NUMPAT reports how many distinct patterns are subscribed to across all clients.

Only exact-channel subscriptions are counted by CHANNELS and NUMSUB: a client subscribed with PSUBSCRIBE will receive matching messages but does not make a channel appear as active. Use these forms for monitoring and debugging, for instance to confirm that a consumer is really attached before publishing.

Syntax#

PUBSUB CHANNELS [pattern]PUBSUB NUMSUB [channel ...]PUBSUB NUMPAT

Arguments#

Argument	Required	Repeatable	Description
`CHANNELS [pattern]`	One form	No	List active channels, optionally filtered by a glob-style pattern.
`NUMSUB [channel ...]`	One form	Yes	Return subscriber counts for the supplied channels.
`NUMPAT`	One form	No	Return the number of active pattern subscriptions.

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	Array of channel names, flat channel/count array, or Integer
RESP3	Array of channel names, flat channel/count array, or Integer

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

PUBSUB CHANNELS events:*

@upstash/redis

Note

This command is not supported yet in @upstash/redis.

upstash_redis

Note

This command is not supported yet in upstash_redis.

ioredis

import Redis from "ioredis";const redis = new Redis(process.env.REDIS_URL!);const result = await redis.pubsub("CHANNELS", "events:*");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.pubSubChannels("events:*");console.log(result);

redis-py

import osimport redisclient = redis.from_url(os.environ["REDIS_URL"])result = client.pubsub_channels("events:*")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.PubSubChannels(context.Background(), "events:*").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.pubsubChannels("events:*");  System.out.println(result);}

redis-rs

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 mut command = redis::cmd("PUBSUB");    command.arg("CHANNELS");    command.arg("events:*");    let result: redis::Value = command.query(&mut connection)?;    println!("{result:?}");    Ok(())}