---
title: "Start appending a chunk to an initialized upload session."
method: POST
path: "/data-repository/data/upload-sessions/{storageId}/appends"
tags: ["Data Repository"]
---

# Start appending a chunk to an initialized upload session.

`POST /data-repository/data/upload-sessions/{storageId}/appends`

## Path parameters

- `storageId` string, required

## Query parameters

- `projectId` string, required

## Request body

- DataRepositoryStartUploadSessionAppendRequest — Request to start appending one chunk to an initialized upload session.
  - `size` integer

## Response `200`

Ok

- DataRepositoryUploadSessionAppend — Append operation initialized for an upload session.
  - `appendId` string
  - `preSignedPutRequest` DataRepositoryPresignedRequest — Pre-signed HTTP request.
    - `headers` DataRepositoryHttpHeader[]
      - `name` string
      - `value` string
    - `url` string

---

[API](https://skmtc.net/simscale/apis/simscale-api.md) · [All operations](https://skmtc.net/simscale/apis/simscale-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/simscale/simscale-api/revisions/53223abaceb7/schema)