# Sign a part

`GET https://api-vod-express.syncwords.com/v1/projects/{id}/uploads/{uploadId}/parts/{partNumber}`

Sign a part

A presigned URL to `PUT` one part’s bytes to, with no other headers. S3’s answer carries the part’s `ETag` header: keep it for completing. Sign each part just before sending it: a URL is valid until `expiresAt`, an hour at most and sometimes less. Counted against a budget of its own, 10,000 a minute per account, not the API’s: a large file is thousands of parts.

**Guide:** [Upload through the API](/vod-express/uploads/api-uploads)

## Parameters

| Name | In | Type | Required | Description |
|---|---|---|---|---|
| `id` | path | string | yes | The project id, a lowercase ULID. |
| `uploadId` | path | string | yes | The `uploadId` `POST /projects/{id}/uploads` answered, URL-encoded. |
| `partNumber` | path | integer | yes | The part, from 1 to `partCount`. |
| `key` | query | string | yes | The `key` `POST /projects/{id}/uploads` answered: the file’s name under `input/`, URL-encoded. |

## Responses

### 200

OK

Example:

```json
{
  "data": {
    "url": "https://sw-vod-express.s3.us-east-1.amazonaws.com/projects/141/01m3k8jnrdw509457nhz7w81bq/input/season%202/episode%2001.mp4?partNumber=1&uploadId=kuoFY0gBzJF3QDKXnQxnv0epFyjyDyUuF20w4yjsjCE4Sq9hkf7Fn.QWqeFXYSSx03HDx…&X-Amz-Signature=…",
    "expiresAt": "2026-09-28T06:43:02.000Z"
  }
}
```

Schema:

```json
{
  "type": "object",
  "required": [
    "data"
  ],
  "properties": {
    "data": {
      "$ref": "#/components/schemas/DownloadLink"
    }
  }
}
```

### 401

No token, or an expired or unknown one: `unauthenticated`.

Example:

```json
{
  "message": "Unauthenticated.",
  "code": "unauthenticated"
}
```

Schema:

```json
{
  "$ref": "#/components/schemas/Error"
}
```

### 403

VOD Express is not available to the account: switched off for it (`vod_express_not_enabled`), or the account is restricted — its access revoked, its trial expired or used up (`account_restricted`, with the reason in `message`).

Example:

```json
{
  "message": [
    "VOD Express is not enabled for your account."
  ],
  "code": "vod_express_not_enabled"
}
```

Schema:

```json
{
  "$ref": "#/components/schemas/Error"
}
```

### 404

No such project, or no such upload for that key — completed, aborted, expired or never started: `upload_not_found`.

Example:

```json
{
  "message": "Upload not found.",
  "code": "upload_not_found"
}
```

Schema:

```json
{
  "$ref": "#/components/schemas/Error"
}
```

### 422

A key or part number that is not valid: `validation_failed`.

Schema:

```json
{
  "$ref": "#/components/schemas/Error"
}
```

### 429

More than 10,000 parts signed in a minute by your account: `too_many_requests`. Wait the seconds `Retry-After` says.

Example:

```json
{
  "message": [
    "Too Many Attempts."
  ],
  "code": "too_many_requests"
}
```

Schema:

```json
{
  "$ref": "#/components/schemas/Error"
}
```

## Schemas

### DownloadLink

`#/components/schemas/DownloadLink`

```json
{
  "type": "object",
  "required": [
    "url",
    "expiresAt"
  ],
  "properties": {
    "url": {
      "type": "string",
      "description": "A presigned S3 URL."
    },
    "expiresAt": {
      "type": "string",
      "format": "date-time",
      "description": "When the URL stops working: an hour from now at most, sooner when the credentials that signed it expire first."
    }
  }
}
```

### Error

`#/components/schemas/Error`

```json
{
  "type": "object",
  "required": [
    "message",
    "code"
  ],
  "properties": {
    "message": {
      "description": "For people. A string, or an array of one string on some statuses: read it as `Array.isArray(m) ? m[0] : m`.",
      "oneOf": [
        {
          "type": "string"
        },
        {
          "type": "array",
          "items": {
            "type": "string"
          }
        }
      ]
    },
    "code": {
      "description": "For programs: stable, one per situation. See the Errors guide.",
      "enum": [
        "bad_request",
        "invalid_output_path",
        "invalid_idempotency_key",
        "unauthenticated",
        "invalid_credentials",
        "forbidden",
        "vod_express_not_enabled",
        "account_restricted",
        "not_found",
        "project_not_found",
        "file_not_found",
        "file_meta_not_found",
        "output_not_found",
        "feed_not_found",
        "upload_not_found",
        "webhook_not_found",
        "webhook_delivery_not_found",
        "aws_access_not_provisioned",
        "storage_connection_not_found",
        "method_not_allowed",
        "conflict",
        "file_exists",
        "project_reads_feed",
        "project_reads_folder",
        "file_processing",
        "project_config_locked",
        "idempotency_in_progress",
        "storage_connection_in_use",
        "payload_too_large",
        "unsupported_media_type",
        "validation_failed",
        "service_start_failed",
        "idempotency_key_reused",
        "webhook_limit_reached",
        "storage_failed",
        "storage_connection_check_failed",
        "storage_connection_folder_only",
        "storage_prefix_taken",
        "build_without_storage_connections",
        "build_has_no_schema",
        "too_many_requests",
        "internal_error",
        "bad_gateway",
        "service_stop_failed",
        "aws_access_failed",
        "platform_unavailable",
        "service_unavailable",
        "build_list_unavailable"
      ]
    },
    "errors": {
      "type": "object",
      "description": "On a 422: each field’s messages, keyed by field name, or by JSON pointer inside `config`.",
      "additionalProperties": {
        "type": "array",
        "items": {
          "type": "string"
        }
      }
    }
  }
}
```