Multipart start

Create a multipart session and receive part size plus presigned PUT URLs.

POST /api/v1/multipart/start

cURL

curl --request POST \
  --url https://upload.autorender.io/api/v1/multipart/start \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
  "file_name": "big-video.mp4",
  "size": 73400320,
  "format": "video/mp4",
  "folder": "uploads/videos",
  "tags": ["campaign", "raw"],
  "metadata": { "source": "mobile-app" },
  "custom_id": "vid_001",
  "random_prefix": false,
  "ttl_seconds": 3600
}'

200

{
  "session_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "part_size": 10485760,
  "parts": [
    "https://storage.example.com/presigned-part-1?X-Amz-Signature=abc",
    "https://storage.example.com/presigned-part-2?X-Amz-Signature=def"
  ]
}

Key type: accepts your public key or a private key. Uploading is the one thing a public key may do, so this endpoint works from browser and mobile code — see key types and scope.

cURL

curl --request POST \
  --url https://upload.autorender.io/api/v1/multipart/start \
  --header 'Authorization: Bearer YOUR_API_KEY' \
  --header 'Content-Type: application/json' \
  --data '{
  "file_name": "big-video.mp4",
  "size": 73400320,
  "format": "video/mp4",
  "folder": "uploads/videos",
  "tags": ["campaign", "raw"],
  "metadata": { "source": "mobile-app" },
  "custom_id": "vid_001",
  "random_prefix": false,
  "ttl_seconds": 3600
}'

200

{
  "session_id": "a1b2c3d4-e5f6-7890-abcd-ef1234567890",
  "part_size": 10485760,
  "parts": [
    "https://storage.example.com/presigned-part-1?X-Amz-Signature=abc",
    "https://storage.example.com/presigned-part-2?X-Amz-Signature=def"
  ]
}

Overview

Starts a multipart upload for large files. The response gives you session_id, part_size (the chunk size in bytes), and parts (presigned URLs, in order). Upload each chunk with Upload parts, then finalize with Multipart complete.

Authentication

Authorization: Bearer YOUR_API_KEY

Workflow

This is step 1 of 3.

1. Multipart start (this endpoint) — get session_id, part_size, and parts.
2. Upload parts — PUT each chunk to the matching presigned URL.
3. Multipart complete — finalize the file in your workspace.

Request body

Field	Type	Required	Description
file_name	string	Yes	Original file name (e.g. big-video.mp4)
size	number	Yes	Total file size in bytes
format	string	Yes	MIME type (e.g. video/mp4, image/jpeg)
folder	string	No	Workspace folder path
tags	string[]	No	Tags
metadata	object	No	Custom metadata
custom_id	string	No	Your tracking id
random_prefix	boolean	No	Random prefix on stored name if true
ttl_seconds	number	No	Lifetime of the presigned URLs, in seconds

Response

Returns session_id, part_size, and parts. Part index i must be uploaded to parts[i].

Authorizations

x-api-key · string · header · required

API key for public endpoints. Can also be provided via Authorization: Bearer

Body

application/json

file_name · string · required

Minimum string length: 1

size · integer · required

Required range: 1 <= x <= 9007199254740991

format · string · required

Minimum string length: 1

folder · string

tags · string[] string

metadata · object

Show child attributes

custom_id · string

random_prefix · boolean

ttl_seconds · integer

Required range: 1 <= x <= 9007199254740991

Response

201

application/json

Session created

Session created

session_id · string · required

uuid · string · required

part_size · integer · required

Required range: -9007199254740991 <= x <= 9007199254740991

min_part_size · integer · required

Required range: -9007199254740991 <= x <= 9007199254740991

parts · string[] · required

Pre-signed S3 upload URLs, one per part

expire_at · integer · required

Unix timestamp when the session expires

Required range: -9007199254740991 <= x <= 9007199254740991

public_key · string · required

workspace_id · string · required

policy · object · required

Show child attributes