> ## 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.

# SETBIT

> Set or clear the bit at offset.

Use `SETBIT` to set a single bit of the string stored at a key to `0` or `1`.

The offset is counted in bits from the start of the value and the reply is the bit's previous value. If the key does not exist, or the offset lies past the end of the current value, the string is first extended with zero bits, so writing to a large offset allocates every byte up to it. Keep offsets dense, for example by mapping each user to a small sequential id.

Bitmaps built this way are read back with [`GETBIT`](/docs/redis/commands/bitmap/getbit), counted with [`BITCOUNT`](/docs/redis/commands/bitmap/bitcount), and combined with [`BITOP`](/docs/redis/commands/bitmap/bitop).

## Syntax

```redis theme={"system"}
SETBIT <key> <offset> <value>
```

## Arguments

| Argument   | Required | Repeatable | Description                        |
| ---------- | -------- | ---------- | ---------------------------------- |
| `<key>`    | Yes      | No         | Redis key targeted by the command. |
| `<offset>` | Yes      | No         | Zero-based bit offset to write.    |
| `<value>`  | Yes      | No         | Bit value to write: `0` or `1`.    |

## 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 previous bit at the offset, `0` or `1` |
| RESP3    | Integer: the previous bit at the offset, `0` 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"}
    SETBIT my-key 0 1
    ```
  </Accordion>

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

    const redis = Redis.fromEnv();

    const originalBit = await redis.setbit(key, 4, 1);
    ```
  </Accordion>

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

    redis = Redis.from_env()
    result = redis.setbit("my-key", 0, 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.setbit("my-key", "0", "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.setBit("my-key", 0, 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.setbit("my-key", 0, 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.SetBit(context.Background(), "my-key", 0, 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.setbit("my-key", 0, true);
      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.setbit("my-key", 0, true)?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [SETBIT](/docs/redis/sdks/py/commands/bitmap/setbit.md)
- [BITCOUNT](/docs/redis/commands/bitmap/bitcount.md)
- [Overview](/docs/redis/sdks/py/commands/overview.md)