> ## Documentation Index
> Fetch the complete documentation index at: https://upstash.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# PUBSUB

> Inspect pub/sub state.

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`](/docs/redis/commands/pub-sub/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

```redis theme={"system"}
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.
</Note>

## Examples

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

<AccordionGroup>
  <Accordion title="Redis CLI" icon="terminal">
    ```bash theme={"system"}
    PUBSUB CHANNELS events:*
    ```
  </Accordion>

  <Accordion title="@upstash/redis" icon="node-js" iconType="brands">
    <Note>
      This command is not supported yet in `@upstash/redis`.
    </Note>
  </Accordion>

  <Accordion title="upstash_redis" icon="python" iconType="brands">
    <Note>
      This command is not supported yet in `upstash_redis`.
    </Note>
  </Accordion>

  <Accordion title="ioredis" icon="node-js" iconType="brands">
    ```ts theme={"system"}
    import Redis from "ioredis";

    const redis = new Redis(process.env.REDIS_URL!);
    const result = await redis.pubsub("CHANNELS", "events:*");
    console.log(result);
    ```
  </Accordion>

  <Accordion title="node-redis" icon="node-js" iconType="brands">
    ```ts theme={"system"}
    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);
    ```
  </Accordion>

  <Accordion title="redis-py" icon="python" iconType="brands">
    ```python theme={"system"}
    import os
    import redis

    client = redis.from_url(os.environ["REDIS_URL"])
    result = client.pubsub_channels("events:*")
    print(result)
    ```
  </Accordion>

  <Accordion title="go-redis" icon="golang" iconType="brands">
    ```go theme={"system"}
    package main

    import (
        "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)
    }
    ```
  </Accordion>

  <Accordion title="jedis" icon="java" iconType="brands">
    ```java theme={"system"}
    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);
    }
    ```
  </Accordion>

  <Accordion title="redis-rs" icon="rust" iconType="brands">
    ```rust theme={"system"}
    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(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [Overview](/docs/redis/sdks/py/commands/overview.md)
- [PUNSUBSCRIBE](/docs/redis/commands/pub-sub/punsubscribe.md)
- [UNSUBSCRIBE](/docs/redis/commands/pub-sub/unsubscribe.md)
- [PSUBSCRIBE](/docs/redis/commands/pub-sub/psubscribe.md)