> ## Documentation Index > Fetch the complete documentation index at: https://heygen-1fa696a7.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Get Asset Upload Part URLs > For an upload created with `multipart`: presigned URLs for the part numbers named, each signed with that part's length. PUT each part to its URL, then call POST /v3/assets/{asset_id}/complete with the multipart_upload_id and every part number with the ETag S3 answered. Ask again for a part whose URL ran out. ## OpenAPI ````yaml /openapi/external-api.json post /v3/assets/{asset_id}/parts openapi: 3.1.0 info: title: HeyGen External API version: 1.0.0 description: >- HeyGen's external API for programmatic AI video creation. See https://docs.heygen.com for full documentation. contact: name: HeyGen Product Infra url: https://heygen.com servers: - url: https://api.heygen.com description: Production security: - ApiKeyAuth: [] - BearerAuth: [] tags: - name: Video Agent description: Create videos from text prompts using AI - name: Videos description: Create, list, retrieve, and delete videos - name: Templates description: Generate videos from reusable templates by replacing their variables - name: Audio description: Search the background-music and sound-effects catalog - name: Video Translate description: Translate videos into other languages - name: AI Clipping description: Turn long-form videos into ready-to-share short clips with captions - name: Batches description: Create and track batches of videos. - name: Video Translation Batches description: Create and track batches of video translations. - name: Lipsync Batches description: Create and track batches of lipsyncs. - name: Asset Batches description: Create and track batches of direct-to-S3 asset uploads. - name: User description: Account information and billing - name: API Keys description: Inspect the API key authenticating the current request - name: Avatars description: List and manage avatars and looks - name: Assets description: Upload files for use in video creation - name: Folders description: >- Create folders to organize videos and translations in the workspace, and look up any folder, Assets library folders included, by id - name: Webhooks description: Manage webhook endpoints and events - name: Lipsync description: Dub or replace audio on existing videos - name: Brand description: >- Brand-related resources — brand kits (colors, fonts, logos) and brand glossaries (custom term translations) - name: HyperFrames description: Render HyperFrames composition zips into video — separate from /v3/videos - name: Models description: '' - name: Filler Word Removal description: '' paths: /v3/assets/{asset_id}/parts: post: tags: - Assets summary: Get Asset Upload Part URLs description: >- For an upload created with `multipart`: presigned URLs for the part numbers named, each signed with that part's length. PUT each part to its URL, then call POST /v3/assets/{asset_id}/complete with the multipart_upload_id and every part number with the ETag S3 answered. Ask again for a part whose URL ran out. operationId: getAssetUploadPartUrls parameters: - name: asset_id in: path required: true schema: type: string description: Unique asset identifier requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MintPartUrlsRequest' responses: '200': description: Successful response content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/MintPartUrlsResponse' '400': description: Invalid request parameters content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' '401': description: Authentication failed content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: unauthorized message: Invalid or expired API key. Verify your x-api-key header. param: null doc_url: null '404': description: Resource not found content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: asset_not_found message: Asset not found. param: null doc_url: null '429': description: Rate limit exceeded content: application/json: schema: type: object properties: error: $ref: '#/components/schemas/StandardAPIError' example: error: code: rate_limit_exceeded message: >- Too many requests. Retry after the duration specified in the Retry-After header. param: null doc_url: null headers: Retry-After: description: Seconds to wait before retrying schema: type: integer security: - ApiKeyAuth: [] - BearerAuth: [] components: schemas: MintPartUrlsRequest: additionalProperties: false description: Presigned URLs for these parts (POST /v3/assets/{asset_id}/parts). properties: multipart_upload_id: description: From the create response. maxLength: 2048 minLength: 1 title: Multipart Upload Id type: string part_numbers: description: Part numbers, from 1, at most the plan's part_count. items: type: integer maxItems: 200 minItems: 1 title: Part Numbers type: array required: - multipart_upload_id - part_numbers title: MintPartUrlsRequest type: object MintPartUrlsResponse: description: Presigned part URLs. properties: parts: items: $ref: '#/components/schemas/PartUrl' title: Parts type: array expires_in_seconds: description: >- Seconds until the part URLs expire. Ask again for a part whose URL ran out. title: Expires In Seconds type: integer required: - parts - expires_in_seconds title: MintPartUrlsResponse type: object StandardAPIError: type: object properties: code: type: string description: Machine-readable error code example: invalid_parameter message: type: string description: Human-readable error message example: Video not found param: type: - string - 'null' description: Which request field caused the error doc_url: type: - string - 'null' description: Link to error documentation errors: type: array description: >- Per-item error details for batch/multi-node failures (e.g. graph compilation errors by node). items: $ref: '#/components/schemas/StandardAPIErrorDetail' request_id: type: string description: >- Request identifier, also returned in the X-HeyGen-Request-Id response header. Include it when contacting support. example: 8c4f0b9e1d2a4f6b9e3c7a1d5f2b8e40 required: - code - message PartUrl: description: Where to PUT one part. properties: part_number: description: Part number, from 1. title: Part Number type: integer upload_url: description: >- Presigned S3 URL. PUT exactly this part's bytes here; its length is signed. title: Upload Url type: string required: - part_number - upload_url title: PartUrl type: object StandardAPIErrorDetail: type: object properties: code: type: string description: Machine-readable error code example: unknown_node_type message: type: string description: Human-readable error message example: Unknown node type node_id: type: string description: Graph node id this error pertains to, if applicable port: type: string description: Port name on the node this error pertains to, if applicable path: type: string description: Field path within the item this error pertains to, if applicable required: - code - message securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: HeyGen API key. Obtain from your HeyGen dashboard. BearerAuth: type: http scheme: bearer description: OAuth2 bearer token. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.