> ## Documentation Index
> Fetch the complete documentation index at: https://upstash-redis-1-18.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# VECTOR.CREATE

> Create a vector index.

Use `VECTOR.CREATE` to create a vector index at a key.

`DIM` fixes the number of elements every vector in the index must have, and `METRIC` fixes how similarity between two vectors is measured. Both are permanent: they decide how the index is built, so they cannot be changed afterwards, and a vector whose length does not match `DIM` is rejected at write time. Pick `COSINE` when only the direction of the embedding matters, which is the usual choice for text embeddings, `DOT` when magnitude carries meaning, and `EUCLIDEAN` when straight-line distance in the embedding space does.

The index occupies its key like any other Redis value, so [`EXISTS`](/redis/commands/generic/exists), [`EXPIRE`](/redis/commands/generic/expire), and [`DEL`](/redis/commands/generic/del) work on it, and creating one at a key already used by another type fails. `EXISTSOK` makes the command succeed instead of failing when the index is already there, which keeps a start-up path idempotent; a mismatch in dimension or metric is still an error.

Vector indexes are an Upstash extension. See the [vector command overview](/redis/commands/vector/overview) for how an index is created, written to, and queried.

## Syntax

```redis theme={null}
VECTOR.CREATE <index> DIM <dimension> METRIC <COSINE | EUCLIDEAN | DOT> [EXISTSOK]
```

## Arguments

| Argument          | Required | Repeatable | Description                                                                                     |
| ----------------- | -------- | ---------- | ----------------------------------------------------------------------------------------------- |
| `<index>`         | Yes      | No         | Key holding the vector index.                                                                   |
| `DIM <dimension>` | Yes      | No         | Number of elements in every vector. Must be between `1` and `32768`.                            |
| `METRIC <metric>` | Yes      | No         | Similarity metric: `COSINE`, `EUCLIDEAN`, or `DOT`.                                             |
| `EXISTSOK`        | No       | No         | Return `0` instead of an error when an index with the same dimension and metric already exists. |

## Important points

* `DIM` and `METRIC` are both required and cannot be changed after the index is created. Use [`VECTOR.DROP`](/redis/commands/vector/vector-drop) and create it again to change either.
* Without `EXISTSOK`, creating an index that already exists returns `ERR Index <index> already exists`.
* With `EXISTSOK`, an existing index with a different dimension or metric returns `ERR Index <index> already exists with a different configuration`.

## 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: `1` if the index was created, `0` if `EXISTSOK` matched an existing index |
| RESP3    | Integer: `1` if the index was created, `0` if `EXISTSOK` matched an existing index |

<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={null}
    VECTOR.CREATE my-index DIM 1536 METRIC COSINE
    ```
  </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={null}
    import Redis from "ioredis";

    const redis = new Redis(process.env.REDIS_URL!);
    const result = await redis.call("VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE");
    console.log(result);
    ```
  </Accordion>

  <Accordion title="node-redis" icon="node-js" iconType="brands">
    ```ts theme={null}
    import { createClient } from "redis";

    const client = await createClient({ url: process.env.REDIS_URL })
      .on("error", console.error)
      .connect();
    const result = await client.sendCommand(["VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE"]);
    console.log(result);
    ```
  </Accordion>

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

    client = redis.from_url(os.environ["REDIS_URL"])
    result = client.execute_command("VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE")
    print(result)
    ```
  </Accordion>

  <Accordion title="go-redis" icon="golang" iconType="brands">
    ```go theme={null}
    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.Do(context.Background(), "VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE").Result()
        if err != nil {
            panic(err)
        }
        fmt.Println(result)
    }
    ```
  </Accordion>

  <Accordion title="jedis" icon="java" iconType="brands">
    ```java theme={null}
    import java.net.URI;

    import redis.clients.jedis.Jedis;

    try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {
      Object result = jedis.sendCommand(() -> "VECTOR.CREATE".getBytes(), "my-index", "DIM", "1536", "METRIC", "COSINE");
      System.out.println(result);
    }
    ```
  </Accordion>

  <Accordion title="redis-rs" icon="rust" iconType="brands">
    ```rust theme={null}
    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("VECTOR.CREATE");
        command.arg("my-index");
        command.arg("DIM");
        command.arg("1536");
        command.arg("METRIC");
        command.arg("COSINE");
        let result: redis::Value = command.query(&mut connection)?;
        println!("{result:?}");
        Ok(())
    }
    ```
  </Accordion>
</AccordionGroup>