# 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
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
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
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
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
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
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
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
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>