# Presign an upload or download for an object in a bucket

**POST** `/projects/{project_id}/branches/{branch_id}/buckets/{bucket_name}/objects/{object_key}/presign`

Returns a presigned URL that transfers bytes directly to or from the
object's bucket on the specified branch, without the caller ever
handling S3 credentials. The `operation` field selects the direction:

- `upload` returns a presigned `PUT` URL (the caller `PUT`s the file
  bytes straight to `url` with the returned `headers`). Authorized with
  project write access.
- `download` returns a presigned `GET` URL (the caller `GET`s the
  bytes straight from `url`). Authorized with project read access.

The platform mints a short-lived credential and builds the SigV4-signed
URL against the branch's S3 data-plane host, returning it together with
the HTTP method, any headers the caller must echo, and the URL's expiry.

Served by the user's session (no customer S3 credentials required).

**Note**: This endpoint is currently in Beta.

Base URL: `https://console.neon.tech/api/v2`

Tags: `Buckets`

## Authorization

Any ONE of the following options authorizes this operation; every scheme listed within an option is required together.

| Option | Scheme | Type | Sent as | Scopes |
| --- | --- | --- | --- | --- |
| Option 1 | `BearerAuth` | `http` | `Authorization: Bearer <token>` | — |
| Option 2 | `CookieAuth` | `apiKey` | cookie `zenith` | — |
| Option 3 | `TokenCookieAuth` | `apiKey` | cookie `keycloak_token` | — |

## Path parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| `project_id` | `string` | Yes | The Neon project ID |
| `branch_id` | `string` | Yes | The Neon branch ID |
| `bucket_name` | `string` | Yes | The bucket name |
| `object_key` | `string` | Yes | The object key. Keys may contain `/`; the `/` characters of nested keys must be percent-encoded (`%2F`) in the path segment. |

## Request body

Required. Media type: `application/json`

### Example request body

```json
{
  "content_type": "string",
  "expires_in_seconds": 900,
  "operation": "download"
}
```

## Responses

| Status | Description | Media type |
| --- | --- | --- |
| `200` | A presigned URL valid until `expires_at`. The caller transfers the object bytes by issuing `method url` with the returned `headers`. | `application/json` |
| `404` | Bucket or branch not found | `application/json` |
| `default` | General Error. The request may or may not be safe to retry, depending on the HTTP method, response status code, and whether a response was received. - If no response is returned from the API, a network error or timeout likely occurred. - In some cases, the request may have reached the server and been successfully processed, but the response failed to reach the client. As a result, retrying non-idempotent requests can lead to unintended results. The following HTTP methods are considered non-idempotent: `POST`, `PATCH`, `DELETE`, and `PUT`. Retrying these methods is generally **not safe**. The following methods are considered idempotent: `GET`, `HEAD`, and `OPTIONS`. Retrying these methods is **safe** in the event of a network error or timeout. Any request that returns a `503 Service Unavailable` response is always safe to retry. Any request that returns a `423 Locked` response is safe to retry. `423 Locked` indicates that the resource is temporarily locked, for example, due to another operation in progress. | `application/json` |

### Example response: 200 — A presigned URL valid until `expires_at`. The caller transfers the
object bytes by issuing `method url` with the returned `headers`.

```json
{
  "expires_at": "2026-06-09T00:00:00Z",
  "headers": {
    "additionalProp1": "string"
  },
  "method": "string",
  "url": "string"
}
```

### Example response: 404 — Bucket or branch not found

```json
{
  "code": "",
  "message": "string",
  "request_id": "string"
}
```

### Example response: default — General Error.

The request may or may not be safe to retry, depending on the HTTP method, response status code,
and whether a response was received.

- If no response is returned from the API, a network error or timeout likely occurred.
- In some cases, the request may have reached the server and been successfully processed, but the response failed to reach the client. As a result, retrying non-idempotent requests can lead to unintended results.

The following HTTP methods are considered non-idempotent: `POST`, `PATCH`, `DELETE`, and `PUT`. Retrying these methods is generally **not safe**.
The following methods are considered idempotent: `GET`, `HEAD`, and `OPTIONS`. Retrying these methods is **safe** in the event of a network error or timeout.

Any request that returns a `503 Service Unavailable` response is always safe to retry.

Any request that returns a `423 Locked` response is safe to retry. `423 Locked` indicates that the resource is temporarily locked, for example, due to another operation in progress.

```json
{
  "code": "",
  "message": "string",
  "request_id": "string"
}
```

## Related pages

- [Accept a project transfer request](./acceptprojecttransferrequest.md)
- [Add an OAuth provider](./addneonauthoauthprovider.md)
- [Add an OAuth provider](./addbranchneonauthoauthprovider.md)
- [Add domain to redirect_uri whitelist](./addbranchneonauthtrusteddomain.md)
- [Add JWKS URL](./addprojectjwks.md)
- [Add trusted redirect URI domain](./addneonauthdomaintoredirecturiwhitelist.md)
- [AI Gateway](./tags/ai-gateway.md)
- [API Key](./tags/api-key.md)
- [Assign or update VPC endpoint](./assignorganizationvpcendpoint.md)
- [Auth](./tags/auth.md)

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