What is flow.ci used for?

flow.ci is a free, Apache-licensed, self-hosted CI/CD server written in Java, offering high availability, auto-scaling runners, online debugging and plugin-based pipeline steps. It is a good fit for self-hosted CI/CD with auto-scaling agents and teams needing high-availability build infrastructure.

Is flow.ci open source?

Yes. flow.ci is open source under the Apache-2.0 licence. Its source code is on GitHub at FlowCI/flow-core-x and is written mainly in Java.

Yes. flow.ci is open source, so the software itself is free to use.

Can I self-host flow.ci?

Yes. flow.ci can be self-hosted on your own server or infrastructure; there is no official hosted version.

What is flow.ci an alternative to?

flow.ci is an open-source alternative to GitHub Actions, TeamCity, Bamboo and CircleCI. Other open-source alternatives to GitHub Actions include Jenkins, Concourse CI and Buildbot.

Is flow.ci actively maintained?

The most recent commit to flow.ci was on 6 April 2025, and the latest release is v1.23.01, published on 3 January 2023. The project has 1.6k stars on GitHub.

flow.ci: open-source alternative to GitHub Actions, TeamCity

About flow.ci

flow.ci is an open-source CI/CD automation server built for teams that want to set up self-hosted continuous integration and delivery with minimal configuration. It is designed to run on public, private or hybrid cloud infrastructure, supporting deployment across multiple instances so job and configuration data is not lost if a single instance fails.

It features auto-scaling build agents on Kubernetes or a plain Linux host, parallel execution of job steps across multiple agents, build caching to speed up pipelines, an online TTY terminal for debugging a running job in real time, and a plugin system where plugins can be written in any language and simply referenced by name in a pipeline step. Each step or step group can run on any Docker image or directly on the native OS, and the server can be started with just three commands alongside ready-made build templates for languages such as Maven, npm, Go, Ruby and Android.

flow.ci is written in Java, requires Docker and Docker Compose, and is released under the Apache-2.0 license. Documentation is available in English and Chinese, with support offered through issues and email.

Key features

High-availability, multi-instance CI/CD server
Auto-scaling build agents on Kubernetes or Linux
Parallel job step execution
Online TTY terminal for debugging jobs
Any-language plugin system
Ready-made language build templates

Good fit for

→Self-hosted CI/CD with auto-scaling agents
→Teams needing high-availability build infrastructure

Built with: Java; Docker
Tags: ci-cd; self-hosted; java; docker; build-automation; continuous-integration

flow.ci: questions and answers

What is flow.ci used for?: flow.ci is a free, Apache-licensed, self-hosted CI/CD server written in Java, offering high availability, auto-scaling runners, online debugging and plugin-based pipeline steps. It is a good fit for self-hosted CI/CD with auto-scaling agents and teams needing high-availability build infrastructure.
Is flow.ci open source?: Yes. flow.ci is open source under the Apache-2.0 licence. Its source code is on GitHub at FlowCI/flow-core-x and is written mainly in Java.
Is flow.ci free?: Yes. flow.ci is open source, so the software itself is free to use.
Can I self-host flow.ci?: Yes. flow.ci can be self-hosted on your own server or infrastructure; there is no official hosted version.
What is flow.ci an alternative to?: flow.ci is an open-source alternative to GitHub Actions, TeamCity, Bamboo and CircleCI. Other open-source alternatives to GitHub Actions include Jenkins, Concourse CI and Buildbot.
Is flow.ci actively maintained?: The most recent commit to flow.ci was on 6 April 2025, and the latest release is v1.23.01, published on 3 January 2023. The project has 1.6k stars on GitHub.