> ## 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.

# DIGEST

> Get the digest of a string value.

Use `DIGEST` to get the digest of a string value.

The reply is a 16-character lowercase hexadecimal XXH3 digest of the stored bytes, null when the key does not exist, and an error when the value is not a string. It is a fast non-cryptographic hash, meant for change detection rather than for security.

Comparing digests lets a client tell whether a large value has changed without transferring it, for instance to decide whether a cached copy is still current. The same digest can be passed to the conditional forms of [`SET`](/docs/redis/commands/string/set) (`IFDEQ`, `IFDNE`) and [`DELEX`](/docs/redis/commands/string/delex), which turns it into a compact compare-and-set token for large values. `DIGEST` is an Upstash extension.

## Syntax

```redis theme={"system"}
DIGEST <key>
```

## Arguments

| Argument | Required | Repeatable | Description                              |
| -------- | -------- | ---------- | ---------------------------------------- |
| `key`    | Yes      | No         | String key whose value should be hashed. |

## Important points

* The reply is a 16-character lowercase hexadecimal XXH3 digest of the stored string bytes.
* A missing key returns null. A key containing a non-string value returns `WRONGTYPE`.

## 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    | Bulk string or Null bulk string or null array |
| RESP3    | Bulk string or Null                           |

<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"}
    DIGEST lock:job-1
    ```
  </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.call("DIGEST", "lock:job-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.digest("lock:job-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.execute_command("DIGEST", "lock:job-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.Digest(context.Background(), "lock:job-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.digestKey("lock:job-1");
      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.digest("lock:job-1")?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>


## Related topics

- [DELEX](/docs/redis/commands/string/delex.md)
- [SET](/docs/redis/commands/string/set.md)
- [EVALSHA](/docs/redis/commands/scripting/evalsha.md)
- [SCRIPT LOAD](/docs/redis/commands/scripting/script-load.md)
- [SCRIPT EXISTS](/docs/redis/commands/scripting/script-exists.md)