Learn what Zenko CloudServer does, its S3-compatible API, multi-cloud backends, deployment options, and why it's free and open source under Apache 2.0.
Zenko CloudServer is an open-source object storage server that implements the Amazon S3 API, letting developers run S3-compatible storage anywhere, not just on AWS. It was originally released by Scality in June 2016 as S3 Server and was renamed CloudServer and folded into the broader Zenko multi-cloud data controller project in 2017.
Scality, the company behind CloudServer, was founded in 2009 and is headquartered in San Francisco, California, with major engineering operations in Paris. CloudServer remains one of Scality's flagship open-source projects and continues to see active development on GitHub.
The project is written in Node.js and released under the Apache License 2.0, making it free to use, modify, and redistribute, including as part of commercial products, without licensing fees.
CloudServer's core feature is full S3 API compatibility, which means existing applications and tools written against Amazon's S3 API, including AWS SDKs for Python, Java, Node.js, and .NET, work against a CloudServer instance without code changes.
It supports multiple storage backends: a local file system backend suited to development and testing, and cloud backends including Amazon S3, Microsoft Azure Blob Storage, and Google Cloud Storage, letting teams present one consistent S3-style API across otherwise incompatible cloud storage systems.
Deployment is designed to be fast, with an official Docker image that lets developers spin up a working instance within minutes, making CloudServer popular for local development, CI/CD pipelines, and testing S3-dependent code without a live AWS account.
Zenko CloudServer is completely free and open source under the Apache License 2.0. There are no license fees, seat costs, or paid tiers for the core software.
Costs come only from the infrastructure you run it on, such as compute, storage, and any commercial cloud backend it's connected to (for example, actual AWS S3 or Azure Blob Storage usage fees when using those as a backend).
Scality also offers commercial, enterprise-grade storage products separately from the open-source CloudServer project for organizations that want vendor support and additional features beyond the free software.
Zenko CloudServer is a free, open-source object storage server that implements the Amazon S3 API, allowing S3-compatible applications to run on-premises or across multiple cloud providers.
Yes, CloudServer is completely free and open source under the Apache License 2.0, with no licensing fees for the software itself.
Zenko CloudServer is maintained by Scality, a data storage company founded in 2009, along with an active open-source community.
CloudServer supports a local file system backend as well as cloud backends including Amazon S3, Microsoft Azure Blob Storage, and Google Cloud Storage.
CloudServer is most commonly deployed via Docker, with an official image that allows a working instance to be running within minutes.
No, it is a separate open-source server that implements the S3 API, so S3-compatible applications can run against it, but it is not operated by AWS.
CloudServer works with standard AWS SDKs for languages including Python, Java, Node.js, and .NET, since it implements the same S3 API those SDKs already use.
It's typically used by developers building S3-compatible applications, enterprises wanting multi-cloud storage flexibility, and teams testing S3-dependent code locally.