---
title: "Append chunk to session"
method: POST
path: "/3/drive/{drive_id}/upload/session/{session_token}/chunk"
tags: ["Drive > Files > File/Directory > Upload > Session"]
---

# Append chunk to session

`POST /3/drive/{drive_id}/upload/session/{session_token}/chunk`

Append more data to an upload session.
<br/><br/><note>
The maximum size per chunk request is 1GB.
</note><br/><note>
To upload a chunk, you must use the ‘upload_url’ returned from the session opening call : <a href="../start">upload/session/start</a>.
</note>

## Path parameters

- `drive_id` integer, required
- `session_token` string, required

## Query parameters

- `chunk_hash` string — The hash of the current chunk. If provided and the uploaded content does not match this hash, an error will be returned.<note>Supported hashing algorithm: md5, sha1, sha256, sha512, xxh3, xxh32, xxh64, xxh128</note>
- `chunk_number` integer, required — The index of the current chunk, <note>The index start at 1</note>
- `chunk_size` integer, required — The size of the current chunk, <note>the unit of size is defined in Bytes</note><note>Please note that the chunk size should be between 1000000 and 1000000000 bytes, except for the last one, which can be smaller as it is the final chunk</note>

## Response `200`

OK

- object
  - `result` 'success' | 'error' | 'asynchronous', required — Result of the HTTP request
  - `data` 91ac10ffUploadsegment
    - `number` integer, required — Index of the chunk to compute the final object correctly
    - `status` 'error' | 'ok' | 'uploading', required — The chunk status during the upload.<note><strong>error</strong>: Something was wrong chunk was not correctly received, retried to send the same chunk.</note><note><strong>ok</strong>: Chunk has been received.</note><note><strong>uploading</strong>: Chunks still uploading.</note>
    - `created_at` integer, required — Timestamp `Upload segment` was created at
    - `size` integer, required — Chunk uploaded size, computed
    - `hash` string, required — Chunk uploaded hash, computed

## Other responses

- `403` — Forbidden
- `503` — Service Unavailable

---

[API](https://skmtc.dev/infomaniak/apis/api-reference-developer-tools.md) · [All operations](https://skmtc.dev/infomaniak/apis/api-reference-developer-tools/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/infomaniak/api-reference-developer-tools/revisions/667aae28fec6/schema)