---
title: "Multipart Upload in S3 | Hostman Docs"
description: "Learn how multipart upload in S3 speeds up large file transfers, improves reliability, supports upload resumption, and works with tools like AWS CLI and s3cmd."
---

> For the complete documentation index for AI agents, see [llms.txt](https://hostman.com/llms.txt).

Multipart upload is a method of transferring large files to [S3 storage](https://hostman.com/products/s3-storage/) by splitting the file into smaller parts (chunks) and uploading them in parallel. This approach speeds up the process and improves reliability: in the event of a failure, you only need to re-upload the corrupted part instead of the entire file. It is especially useful for handling large files and working with unstable network connections.

## Advantages of Multipart Upload

-   **Faster Data Transfer**: Parallel uploads of multiple parts reduce the time required to transfer large files.
-   **Flexibility**: The ability to pause and resume uploads makes it easier to work with unstable connections.
-   **Fault Tolerance**: Errors during the transfer of individual parts can be fixed by re-uploading just those parts.

> [!NOTE]
> Note: If a multipart upload is interrupted, the incomplete file parts won’t appear in the bucket interface but will still occupy storage space on the server. To free up this space, you need to manually finalize or cancel the upload.

## Use Cases

Many tools and libraries for working with [S3](https://hostman.com/products/s3-storage/) support multipart uploads and allow you to configure the size of the parts. Below are some tools that support multipart uploads:

-   [AWS CLI](https://hostman.com/docs/s3/tools/aws-cli/#multipart-upload)
-   [s3cmd](https://hostman.com/docs/s3/tools/s3cmd/#managing-interrupted-multipart-uploads)
-   [S3 Browser](https://hostman.com/docs/s3/tools/s3-browser/#managing-interrupted-multipart-uploads)

These tools provide flexible options for configuring the upload process, enabling you to optimize data transfer based on your needs and network conditions.