---
title: "Create Multipart Upload Targets"
method: POST
path: "/api/workspace/uploads/multipart"
tags: ["runtime_mutations", "workspace-uploads"]
---

# Create Multipart Upload Targets

`POST /api/workspace/uploads/multipart`

Open an S3 multipart upload per file, for files past the single-PUT cap.

## Request body

- MultipartCreateRequest
  - `files` MultipartCreateFile[], required
    - `relative_path` string, required
    - `size` integer, required
    - `content_type` string
    - `mtime_ns` integer, nullable

## Response `200`

Successful Response

- MultipartCreateResponse
  - `files` MultipartUploadTarget[], required
    - `relative_path` string, required
    - `upload_id` string, nullable, required
    - `s3_upload_id` string, required
    - `part_size` integer, required
    - `part_count` integer, required
    - `parts` PresignedPart[], required
      - `part_number` integer, required
      - `url` string, required
  - `expires_in_seconds` integer, required
  - `max_upload_bytes` integer, required

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.net/quadrillion/apis/quadrillion-cloud-api.md) · [All operations](https://skmtc.net/quadrillion/apis/quadrillion-cloud-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/quadrillion/quadrillion-cloud-api/revisions/f90b0af01f1e/schema)