Open-source TeamCity alternatives

Harness Open Source is a developer platform written in Go that bundles source code hosting, automated pipelines, hosted development environments and artifact registries in one product. The idea is to give a team a complete, self-run DevOps toolchain rather than separate services for repositories, builds and package storage.

Its hosted development environments are called Gitspaces, and the platform also includes registries for build artifacts. Harness is presented as the next generation of Drone: Drone focused only on continuous integration, whereas Harness adds code hosting and developer environments. The maintainers say the goal is eventual parity with Drone's pipeline capabilities so users can migrate, and a snapshot of Drone lives on a separate branch so it can keep developing.

You can run Harness locally from the published Docker image and open it on port 3000. The image stores its database and repositories in a volume, so a bind mount or named volume is strongly recommended to avoid losing data when the container stops. The project is Apache-2.0 licensed, with documentation at developer.harness.io.

Jenkins is an open-source automation server written in Java. Teams use it to automate parts of their development workflow, including building projects, running tests to catch bugs early, performing static code analysis and deploying software. The README states that more than 2,000 plugins extend it to automate nearly any task. It is released under the MIT license, and its topics include continuous integration, delivery and pipelines as code.

The project distributes official downloads as WAR archives, Docker images, and native packages or installers for several Linux distributions and Windows. Two release lines exist: weekly releases carrying all new features and fixes, and Long-Term Support releases that receive periodic backported bug fixes. The repository links to contributing guidelines, good first issues, developer documentation, governance and adopters information. As a self-managed server, you operate and secure your own Jenkins instance.

Concourse is an automation system written in Go, most often used for CI/CD and built to scale from simple to complex pipelines. It is deliberately opinionated: the project emphasizes idempotency, immutability, declarative configuration, stateless workers and reproducible builds.

It is distributed as a single concourse binary on the releases page, and other supported formats include a Docker image, a Kubernetes Helm chart and a BOSH release. A quick start walks through running it locally. Topics show that tasks run in containers using containerd and runc, and the web interface was built with Elm.

Concourse is licensed under Apache-2.0. It is run on your own infrastructure by teams that prefer pipelines described as code, with each job's inputs and outputs explicit, over scripts configured through a UI. It suits platform and DevOps teams wanting repeatable, container-isolated build and deploy pipelines.

GoCD is a continuous delivery server that helps automate and streamline the build, test and release cycle so that software can be delivered continuously with fewer worries. The repository is the project's main code base, and the project is sponsored by Thoughtworks.

Newcomers can use the Test Drive GoCD page to build a first pipeline while learning the key concepts, download releases from the website and read the documentation for detailed help. It is predominantly a Java and TypeScript project that uses the Spring Framework, SparkJava and MithrilJS, is built with Gradle and Webpack and runs inside Eclipse Jetty, with a few older parts rendered server-side in JRuby on Rails. GoCD itself is built with GoCD.

The security policy explains how issues are reported, and contributing guides cover the development environment. GoCD is licensed under Apache-2.0 and is hosted by you. It suits teams that model deployment pipelines with explicit stages and dependencies across several services.

Buildbot is an open-source continuous integration framework written in Python. Rather than a fixed service with a rigid workflow, it is a toolkit for automating the whole software development cycle, from compiling and testing code to packaging and releasing it, with configuration expressed in Python.

The project's site presents it as a framework with batteries included, covering automated build, test and release jobs, a web interface, and a tutorial and documentation to get started. A master process coordinates build workers that can run on different platforms, which makes it a good fit for projects that need to test across many operating systems and configurations. The site also lists success stories and a Metabuildbot used to build Buildbot itself.

Buildbot is licensed under GPL-2.0 and is typically self-hosted, with community support through a mailing list and IRC. It suits teams that want a highly customizable CI system they control, particularly for complex or multi-platform build setups.

CDS, the Continuous Delivery Service, is an enterprise-oriented continuous delivery and DevOps automation platform written in Go and developed by OVH. It lets teams model build, test and deployment processes as workflows and run them across their infrastructure.

The platform offers a UI where complex workflows can be built, started and inspected down to the logs, and a command-line client called cdsctl that can script everything and includes commands such as a shell for browsing projects and workflows without a browser. Workflows can also be defined as code, according to the README, and the project is described as under active development with published documentation.

CDS is licensed under BSD-3-Clause and is self-hosted by organizations that want to run their own CI/CD platform. It suits platform engineering teams looking for an open, scriptable alternative to commercial pipeline tools.

bk-ci, also called Blueking Continuous Integration (蓝盾), is a free and open-source CI service for automating build, test, and release workflows. It handles compiling, static code analysis, running tests to catch bugs early, and deployment and release. The documentation is available in Chinese and English, and the input lists its license only as other. It is written in Kotlin and Java.

The platform is described as eight core services: pipelines that visualize a team's development process, code checking powered by BK-CodeCC, a code repository service that links existing source hosting, credential management, environment management for build machines, a store of pipeline plugins and templates, compile acceleration for C/C++ and Unreal Engine builds, and an artifact repository supporting formats such as Maven, npm, PyPI, Docker, Helm, and NuGet on COS or S3 storage. A cloud desktop service is also listed.

The README warns that the master branch can be unstable and that users should install from releases. bk-ci suits enterprises, particularly Chinese-speaking teams and game studios, that want a self-managed CI platform covering pipelines, artifacts, and build acceleration.

Semaphore is a continuous integration and delivery platform that helps product teams build, test and ship software. Pipelines are defined in YAML, can run jobs in parallel, and work with containers, Kubernetes and multi-cloud environments. The project presents it as a delivery platform for AI-driven development as well as traditional workflows.

The code base is written mainly in Elixir and Go, and the repository describes three flavors. The Community Edition is free and open source under Apache 2.0 and meant for teams running Semaphore on their own infrastructure with community support. The Enterprise Edition adds features for larger organizations under a commercial licence with professional support. Semaphore Cloud is the hosted option at semaphoreci.com.

Installing the self-hosted version is said to take roughly 10 to 30 minutes, with detailed guides for different methods, and the repository links to documentation, a roadmap, governance information and a project board. It suits engineering teams that want a modern CI/CD system they can run themselves, or prefer a hosted service with the same engine.

Abstruse is a free and open-source continuous integration and delivery platform. It runs tests and builds for your code on infrastructure you operate, using Docker to isolate jobs, and reports results through a web interface.

Version 2 is a rewrite in Go; the 1.x line was based on Node.js. By default it runs as a single-node cluster with a server and a configurable number of workers, and the cluster can be extended with additional nodes when more capacity is needed. A quick-start Docker setup launches the abstruse-server, one abstruse-worker and a MySQL database, followed by a browser-based installation wizard.

Abstruse is licensed under MIT and is self-hosted. A live demo is available with a read-only user, so you can look around before installing. Building from source requires Node.js, yarn and Go, and the project describes itself as lightweight compared with a typical CI server.

PHP Censor is a self-hosted continuous integration server built for PHP projects. It is a fork of PHPCI and lets teams automatically fetch code, install dependencies, run tests and quality checks, and send notifications about the results from a server they control.

Projects can be cloned from GitHub, Bitbucket, GitLab, generic Git, Mercurial, Subversion or a local directory. Builds can set up database tests for PostgreSQL, MySQL and SQLite, install Composer dependencies, run PHPUnit, Atoum, Behat, Codeception and PHPSpec, and apply linting and static analysis tools such as PHP CodeSniffer, PHP Mess Detector and PHPLoc. Plugins such as Deployer, Phing, Grunt and Gulp are included, along with notifications to email, Slack, IRC and Telegram, and LDAP authentication.

The server needs a Unix-like OS, PHP 7.4 or newer, Nginx or Apache, a MySQL, MariaDB or PostgreSQL database and a Beanstalkd queue; Windows is not supported. It is released under the BSD-2-Clause license, with version 2.1 as the current stable line.