> ## 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.

# 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`](/docs/redis/commands/generic/exists), [`EXPIRE`](/docs/redis/commands/generic/expire), and [`DEL`](/docs/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](/docs/redis/commands/vector/overview) for how an index is created, written to, and queried.

## Syntax

```redis theme={"system"}
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`](/docs/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.

## Examples

TCP examples use the TLS `REDIS_URL` from the Upstash console. REST examples use `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN`.

> **Redis CLI**
>
> ```bash theme={"system"}
> VECTOR.CREATE my-index DIM 1536 METRIC COSINE
> ```

> **@upstash/redis**
>
> ```ts theme={"system"}
> import { Redis } from "@upstash/redis";
>
> const redis = Redis.fromEnv();
>
> const index = await redis.vector.createIndex({
>   name: "my-index",
>   dimension: 1536,
>   metric: "COSINE",
> });
> ```

> **upstash\_redis**
>
> ```python theme={"system"}
> from upstash_redis import Redis
>
> redis = Redis.from_env()
>
> index = redis.vector.create_index(name="my-index", dimension=1536, metric="COSINE")
> ```

> **ioredis**
>
> ```ts theme={"system"}
> 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);
> ```

> **node-redis**
>
> ```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.sendCommand(["VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE"]);
> console.log(result);
> ```

> **redis-py**
>
> ```python theme={"system"}
> 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)
> ```

> **go-redis**
>
> ```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.Do(context.Background(), "VECTOR.CREATE", "my-index", "DIM", "1536", "METRIC", "COSINE").Result()
>     if err != nil {
>         panic(err)
>     }
>     fmt.Println(result)
> }
> ```

> **jedis**
>
> ```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.sendCommand(() -> "VECTOR.CREATE".getBytes(), "my-index", "DIM", "1536", "METRIC", "COSINE");
>   System.out.println(result);
> }
> ```

> **redis-rs**
>
> ```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("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(())
> }
> ```


## Related topics

- [VECTOR.ADD](/docs/redis/commands/vector/vector-add.md)
- [Vector commands](/docs/redis/commands/vector/overview.md)
- [Langflow with Upstash Vector](/docs/vector/integrations/langflow.md)
- [VECTOR.COUNT](/docs/redis/commands/vector/vector-count.md)
- [VECTOR.DROP](/docs/redis/commands/vector/vector-drop.md)


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