---
id: ossfs
version: "2025.5.0"
license: Apache-2.0
license_treatment: permissive
maintenance: aging
---

# ossfs — fsspec filesystem for OSS

License: permissive · Maintenance: aging · Downloads: 117.2K/mo

## What it is and what it does

OSSFS is a Python adapter that exposes Alibaba Cloud's Object Storage Service (OSS) through the fsspec filesystem abstraction layer. It lets you read, write, and list objects in OSS buckets using the same standard API you would use for local files or other cloud storage backends, making it easy to swap storage backends in data pipelines and applications.

The package offers two modes: a synchronous variant using the official oss2 library, and an asynchronous variant using aiooss2 for concurrent bulk operations. According to the documentation, the async version can be significantly faster for workloads involving many small files—the example shows a 10x speedup for uploading 1200 small files. Both modes integrate seamlessly with fsspec, so you can use them with tools and libraries that already support fsspec.

Use it for:

- Access OSS objects in data pipelines and machine learning workflows using standard fsspec APIs.
- Migrate data between local storage and OSS without changing application code.
- Perform concurrent bulk uploads or downloads of many small files using the async variant.
- Integrate OSS storage with DVC or other fsspec-aware tools for reproducible data workflows.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

OSSFS provides a Python interface to Alibaba Cloud's Object Storage Service (OSS) through the fsspec standard API, enabling file-like operations on OSS objects with both synchronous and asynchronous backends.

Yes, if you work with Alibaba Cloud OSS and want a standard fsspec interface. The package is stable (Beta status), supports current Python versions (3.8–3.13), has no known vulnerabilities, and low install friction. The 464-day release gap suggests slower maintenance, so verify that aiooss2 support meets your needs before committing to the async variant.

## Install

pip install ossfs
uv add ossfs
poetry add ossfs

## Installing ossfs

Before you install: Low install friction with a pure-Python wheel. Maintenance is aging—last release was 464 days ago—but the repository remains active with a recent commit on 2025-05-07 and no archived status.

License in practice: Distributed under Apache-2.0, a permissive open-source license that allows commercial use, modification, and distribution with minimal restrictions.

Quickstart:

pip install ossfs

import ossfs
fs = ossfs.OSSFileSystem(endpoint='http://oss-cn-hangzhou.aliyuncs.com')
with fs.open('/bucket/file') as f:
    data = f.read()

Requires OSS credentials (access key ID and secret) and a valid OSS endpoint URL; async variant (AioOSSFileSystem) depends on the third-party aiooss2 backend which is not officially supported.

Verify before relying:

- Whether aiooss2 dependency is installed by default or requires explicit opt-in for async functionality.
- Current status of aiooss2 official support and feature parity with oss2.
- Whether the 464-day gap since last release indicates active maintenance or dormancy.

## Package facts

- License: Apache-2.0 (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: aging
- Downloads: 117.2K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

oss object storage python, alibaba cloud oss filesystem, fsspec oss adapter, async oss file operations, cloud storage python interface, oss2 fsspec wrapper, object storage service python, cloud-storage, alibaba-oss, async-io

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