> ## 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.

# BITPOS

> Find first bit set or clear in a string.

Use `BITPOS` to find the position of the first bit set to `0` or `1` in a string.

The whole value is searched unless `<start>` and `<end>` are given, and those are byte offsets by default or bit offsets when `BIT` is given. Both ends are inclusive and may be negative to count backwards from the end of the value. The reply is always an absolute bit position counted from the start of the string, or `-1` when no matching bit is found.

One edge case is worth remembering: when you look for a `0` in a string of all ones and give no explicit end, the reply is the position of the first bit past the end of the string, because the value is treated as if it were followed by an infinite run of zero bits. Bounding the search with an explicit range returns `-1` in the same situation.

## Syntax

```redis theme={"system"}
BITPOS <key> <bit> [<start> [<end> [BYTE | BIT]]]
```

## Arguments

| Argument                        | Required | Repeatable | Description                                                                                         |
| ------------------------------- | -------- | ---------- | --------------------------------------------------------------------------------------------------- |
| `<key>`                         | Yes      | No         | Redis key targeted by the command.                                                                  |
| `<bit>`                         | Yes      | No         | Bit value to look for: `0` or `1`.                                                                  |
| `<start> [<end> [BYTE \| BIT]]` | No       | No         | Range to search. Offsets are byte-based unless `BIT` is given; negative offsets count from the end. |

## 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: the position of the first matching bit, or `-1` |
| RESP3    | Integer: the position of the first matching bit, or `-1` |

<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"}
    BITPOS my-key 1
    ```
  </Accordion>

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

    const redis = Redis.fromEnv();

    await redis.bitpos("key", 1);
    ```
  </Accordion>

  <Accordion title="upstash_redis" icon="python" iconType="brands">
    ```python theme={"system"}
    from upstash_redis import Redis

    redis = Redis.from_env()
    result = redis.bitpos("my-key", 1)
    print(result)
    ```
  </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.bitpos("my-key", "1");
    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.bitPos("my-key", 1);
    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.bitpos("my-key", 1)
    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.BitPos(context.Background(), "my-key", 1).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.bitpos("my-key", true);
      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("BITPOS");
        command.arg("my-key");
        command.arg("1");
        let result: redis::Value = command.query(&mut connection)?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [BITPOS](/docs/redis/sdks/py/commands/bitmap/bitpos.md)
- [Changelog](/docs/redis/overall/changelog.md)
- [Overview](/docs/redis/sdks/py/commands/overview.md)