---
title: "Start a chunked server-hashed Library upload"
method: POST
path: "/workspaces/{workspaceId}/library/chunked/initiate"
tags: ["Library"]
---

# Start a chunked server-hashed Library upload

`POST /workspaces/{workspaceId}/library/chunked/initiate`

## Request

- Base URL: `https://api.rendley.com/v1`
- URL: `https://api.rendley.com/v1/workspaces/{workspaceId}/library/chunked/initiate`
- Auth: API key in header `Authorization`

Hashless large-file transport for API/MCP clients that cannot compute the content hash: parts are PUT to the API strictly in order, the server hashes them incrementally while forwarding to storage, and the hash exists at complete — computed server-side. Files under the proxy cap should use the single-call proxy upload instead.

## Path parameters

- `workspaceId` string, required

## Request body

- TypesLibraryChunkedInitInput
  - `duration` number
  - `file_size` integer, required
  - `mime_type` string
  - `original_file_name` string
  - `project_id` string: ProjectID, when set, adds the asset to that project's media once the upload completes through its upload_url.
  - `source` 'uploaded' | 'export'

## Response `200`

OK

- object
  - `data` object: Success data
    - `part_size_max` integer
    - `part_size_min` integer: Parts must be sent sequentially (1, 2, 3, ...) within these size bounds; only the final part may be smaller than the minimum.
    - `upload_id` string
    - `upload_url` string: UploadURL, for MCP callers, takes the whole file as one PUT (or parts as `PUT <upload_url>&part=N`) with no other credential; the upload completes when the last byte arrives.
  - `error` HttpResponseAPIError
    - `code` string
    - `fields` HttpResponseFieldError[]
      - `field` string
      - `message` string
    - `message` string
  - `meta` unknown

## Other responses

- `400`: Bad Request
- `401`: Unauthorized

---

[API](https://skmtc.dev/rendley/apis/rendley-api.md) - [All operations](https://skmtc.dev/rendley/apis/rendley-api/llms.txt) - [OpenAPI document](https://skmtc.dev/rendley/apis/rendley-api/revisions/7eb8713bbf78?raw)