> ## 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.

# BLPOP

> Pop from the head of a list, blocking until an element arrives.

Use `BLPOP` to pop an element from the head of the first non-empty list, blocking until one has an element or the timeout expires.

It is the blocking form of [`LPOP`](/docs/redis/commands/list/lpop) and it accepts several keys, which are checked in the order given, so earlier keys act as higher priority queues. The reply names the key the element came from together with the element itself, which matters when you are waiting on more than one queue.

The timeout is in seconds, may be fractional, and `0` waits indefinitely; when it expires the reply is null. Blocking lets a worker wait for work without polling, which cuts both latency and wasted commands. When several clients are blocked on the same key they are served in the order they started waiting.

## Syntax

```redis theme={"system"}
BLPOP <key> [<key> ...] <timeout>
```

## Arguments

| Argument    | Required | Repeatable | Description                                |
| ----------- | -------- | ---------- | ------------------------------------------ |
| `<key>`     | Yes      | Yes        | Redis key targeted by the command.         |
| `<timeout>` | Yes      | No         | Seconds to block; `0` blocks indefinitely. |

## Important points

* A blocking form holds the request until data arrives or its timeout expires. Set the client/network timeout longer than the command timeout.

## 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    | Null bulk string or null array, or two-element key/value array |
| RESP3    | Null, or two-element key/value array                           |

<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"}
    BLPOP my-key 1.5
    ```
  </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.blpop("my-key", "1.5");
    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.blPop("my-key", 1.5);
    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.blpop(["my-key"], timeout=1.5)
    print(result)
    ```
  </Accordion>

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

    import (
        "context"
        "fmt"
        "os"
        "time"

        "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.BLPop(context.Background(), 1500*time.Millisecond, "my-key").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.blpop(1.5, "my-key");
      System.out.println(result);
    }
    ```
  </Accordion>

  <Accordion title="redis-rs" icon="rust" iconType="brands">
    ```rust theme={"system"}
    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.blpop("my-key", 1.5)?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [REST API](/docs/redis/features/restapi.md)
- [LPOP](/docs/redis/commands/list/lpop.md)
- [BRPOP](/docs/redis/commands/list/brpop.md)