through the alias are served from its target namespace; writes to an alias
name are rejected. Many aliases can resolve to the same namespace.

The call returns once the alias resolves on every reader, which takes about
a second; size client timeouts accordingly. A 409 whose
`details.metadata.target_namespace` matches the requested target carries
the same guarantee: your earlier call committed and the alias is live.

For guidance and examples, see [Manage namespace aliases](/guides/manage-data-namespace-aliases-manage-aliases).

:::code-group
```bash curl
# To get the unique host for an index,
# see https://docs.pinecone.io/guides/manage-data/target-an-index
PINECONE_API_KEY="YOUR_API_KEY"
INDEX_HOST="INDEX_HOST"

curl -X POST "https://$INDEX_HOST/namespace-aliases" \
    -H "Api-Key: $PINECONE_API_KEY" \
    -H "Content-Type: application/json" \
    -H "X-Pinecone-Api-Version: 2026-07" \
    -d '{
        "name": "dataset",
        "target_namespace": "dataset_v1"
    }'
```
:::

`POST /namespace-aliases`

:::code-group
```json title="200"
{
  "name": "dataset",
  "target_namespace": "dataset_v1",
  "created_at": "2026-09-01T12:00:00.000Z",
  "updated_at": "2026-09-01T12:00:00.000Z"
}
```

```json title="400"
{
  "code": 123,
  "message": "<string>",
  "details": [
    {
      "typeUrl": "<string>",
      "value": "<string>"
    }
  ]
}
```

```json title="409"
{
  "code": 123,
  "message": "<string>",
  "details": [
    {
      "typeUrl": "<string>",
      "value": "<string>"
    }
  ]
}
```

```json title="4XX"
{
  "code": 123,
  "message": "<string>",
  "details": [
    {
      "typeUrl": "<string>",
      "value": "<string>"
    }
  ]
}
```

```json title="5XX"
{
  "code": 123,
  "message": "<string>",
  "details": [
    {
      "typeUrl": "<string>",
      "value": "<string>"
    }
  ]
}
```
:::

#### Authorizations

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `Api-Key` | `string` | - |  |

An API Key is required to call Pinecone APIs. Get yours from the [console](https://app.pinecone.io/).

#### Headers

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `X-Pinecone-Api-Version` | `string` | `2026-07` | Required date-based version header |

#### Body

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `name` | `string` | - | The name of the alias to create. Must be 1-512 characters of printable ASCII, excluding space and / ? # % & = \ ; +, and cannot be __default__, . or ... It shares one uniqueness space with namespace names: it cannot be the name of an existing namespace or alias, and no namespace can later be created under it. Required string length: 1 - 512. Example: dataset |

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `target_namespace` | `string` | - | The namespace the alias resolves to. Must be an existing, active namespace in the index; an alias cannot point to another alias. To point the alias at the default namespace, use __default__. Required string length: 1 - 512. Example: dataset_v1 |

#### Response

`200` — A successful response.

A description of a namespace alias and the namespace it resolves to.

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `name` | `string` | - | The name of the alias. Immutable after creation. Example: dataset |

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `target_namespace` | `string` | - | The namespace the alias resolves to. Changed only by repointing the alias. The default namespace is represented as __default__. Example: dataset_v1 |

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `created_at` | `string` | - | The time the alias was created. Example: 2026-09-01T12:00:00.000Z |

| Prop | Type | Default | Description |
| --- | --- | --- | --- |
| `updated_at` | `string` | - | The time the alias was last repointed. Advances on every repoint, including a repoint to the alias's current target; equals created_at until the first repoint. Example: 2026-09-01T12:00:00.000Z |

## Related pages

- [List namespace aliases](./database-data-plane-list-namespace-aliases.md)
- [Describe a namespace alias](./database-data-plane-describe-namespace-alias.md)
- [Repoint a namespace alias](./database-data-plane-repoint-namespace-alias.md)
- [Delete a namespace alias](./database-data-plane-delete-namespace-alias.md)

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