9 Best Free & Open Source CI/CD Tools For 2025

With the increasing demand for rapid deployment cycles and high-quality software, CI/CD tools have become essential for automating the integration and delivery of code changes. This automation not only accelerates development but also improves collaboration among teams, ensuring that software updates can be released more frequently and reliably.

In this article, you'll explore the best open-source CI/CD tools and their key features to help you make an informed choice.

What are CI/CD Tools?

CI/CD tools are software platforms that help developers automate the processes of building, testing, and delivering code. These tools are essential in modern software development as they make it easier to manage changes in code, ensure quality, and deploy applications quickly.

Continuous Integration (CI) focuses on merging code changes from multiple developers into a shared repository on a regular basis. With each change, automated tests are run to catch and fix issues early and maintain stable base code.

Continuous Delivery or Deployment (CD), on the other hand, takes things a step further by automating the process of delivering tested code to production. This ensures software updates are rolled out quickly with minimal risk. Together, CI/CD enables faster development cycles and more reliable software releases.

Benefits Of Using Open-Source CI/CD Tools

Here are some key advantages of adopting open-source CI/CD tools:

Improved Code Quality

CI/CD tools facilitate continuous integration and testing of code changes. This helps catch bugs early in the development cycle, reducing the possibility of issues reaching production. So, you can deliver higher-quality code, which translates into a better final product for your users.

Reduced Risk and Downtime

Automated deployment pipelines minimize human error, ensuring that updates are consistent and less prone to failures. Furthermore, many CI/CD tools support rollback options, allowing teams to quickly revert to a stable version if issues arise. This ensures minimal disruption for end-users.

Cost-Effectiveness

Open-source CI/CD tools are free to use, which significantly reduces the costs associated with software development and deployment. This accessibility and flexibility make them a great choice for startups or small businesses that operate on limited budgets.

Enhanced Collaboration

CI/CD tools foster closer collaboration among development, testing, and operations teams by establishing a shared platform for managing the software delivery process. They enable teams to work together effortlessly, share code changes, and detect errors early, resulting in increased productivity.

Large Community Support

Open-source CI/CD tools are backed by robust community support. A large community of users contributes to the continuous improvement of these tools, providing a wealth of resources and shared knowledge. This collaborative environment makes it easier for you to troubleshoot issues and adopt best practices.

Learn How Faros AI Saw Benefit with Airbyte's CI/CD Pipeline

Airbyte is an open-source data movement platform that helps you consolidate data from multiple sources into your preferred destination. It offers an extensive catalog of 550+ pre-built connectors that facilitate integration with various CI/CD tools, such as Jenkins and Harness, to optimize your workflows.

Now, let’s understand how Faros AI integrated Airbyte into its data engineering platform.

Faros AI is a comprehensive and extensible data and analytics platform for software engineering. It provides an open-source Community Edition (CE) that offers a unified view of engineering operations by connecting data from various tools across the software development lifecycle.

To streamline this process, Faros CE leveraged Airbyte to ingest data from multiple operational sources, such as GitHub and Jira, into Faros. Faros utilized Airbyte’s pre-built connectors to extract data from dispersed sources as well as CDK to create a Faros custom destination connector. This connector processes the data streams extracted by Airbyte's source connectors and stores them in Faros data models.

Using Airbyte, Faros AI now gets a unified view of engineering operations data. For example, the PR (pull request) Cycle Time statistic (as shown in the screenshot) is calculated by combining data from multiple sources ingested via Airbyte. This facilitates engineering teams in identifying inefficiencies and optimizing their CI/CD pipelines.

9 Best Open-Source CI/CD Tools

Here are some of the best CI/CD open-source tools:

1. Jenkins

Jenkins is an open-source automation server that helps you streamline various tasks related to building, testing, and deploying software. Developed in Java, it is compatible with multiple operating systems, including Windows, Linux, macOS, and other Unix-like systems. You can install Jenkins via Docker or run it independently on any machine that has a Java Runtime Environment (JRE) installed.

Key Features of Jenkins

Pipeline as Code: Jenkins enables you to define different pipelined processes as code in Jenkinsfile, which is stored and versioned in the source repository. This makes it easier to access, run, and manage jobs for multiple deployment pipelines used in the CI/CD workflows.

‍Extensible Plugin Ecosystem: It offers over a thousand different plugins that you can use to enhance the functionality of a Jenkins environment according to your specific needs.

‍Distributed Builds: Jenkins supports distributed builds, executing jobs across multiple machines or agents. This significantly reduces build times and optimizes resource use, which is particularly beneficial for large-scale projects.

License

Jenkins is licensed under the MIT license.

G2 Rating

4.4 out of 5.

2. GitHub Actions

GitHub Actions enables you to automate all your software development processes, such as building, testing, and deploying applications. You can set up workflows to build and test each pull request to your repository or deploy merged pull requests to production. GitHub supports Windows, Linux, and macOS virtual machines to run your workflows. You can also self-host runners in your own data center or cloud infrastructure.

Key Features of GitHub Actions

Workflow Templates: The platform offers ready-to-use workflow templates for various languages. For example, if you use Node.js, GitHub will recommend a workflow template file that installs your Node.js packages and runs your tests.

‍Matrix Builds: This feature enables you to use variables in a single job definition to automatically generate multiple job runs based on the different combinations of the variables. This helps test your code across multiple language versions or operating systems.

‍Secrets Management: GitHub Actions provides a built-in secret store to manage sensitive information, such as API keys and passwords. This ensures that private data is never exposed in the code or logs.

License

GitHub Actions is released under the MIT License.

G2 Rating

4.7 out of 5.

3. CircleCI

CircleCI is a CI/CD tool that helps you to build and deploy software. It supports configuration as code. The entire delivery process from building to deployment is orchestrated through a single file named config.yml for streamlined management of workflows.

Key Features of CircleCI

Docker Layer Caching (DLC): This feature is useful if you frequently build Docker images for your CI/CD processes. Docker images are packages that include the libraries and dependencies to run an application. DLC saves time by caching and reusing unchanged layers of these images on subsequent job runs instead of rebuilding the entire image every time.

‍Automated Testing: CircleCI lets you automatically test your code before merging changes to catch bugs early and maintain code quality. It also facilitates integration with various testing tools and frameworks like Mocha, JUnit, Selenium, XCTest, and more.

‍Orbs: Orbs are reusable packages of configuration elements, such as jobs, commands, and executors. They simplify the setup of common tasks and integrations by providing pre-configured snippets of code that can be easily shared and imported into your projects.

License

CircleCI is under the MIT License.

G2 Rating

4.4 out of 5.

4. GitLab

GitLab, a web-based Git repository management tool, offers GitLab CI/CD, a powerful DevOps solution for automating the entire software development lifecycle. It helps you streamline processes from code creation and testing to deployment and monitoring. By using GitLab-hosted Runners, you can run CI/CD jobs on GitLab.com without the hassle of managing your own infrastructure.

Key Features of GitLab

Merge Trains: This feature helps you manage multiple merge requests by queuing them in a sequence. Each request is tested in order to ensure that changes don't conflict with each other, which helps maintain the integrity of your codebase.

‍CI/CD Components: These are reusable building blocks for pipelines. You can create, share, and use components to simplify and standardize your CI/CD configurations, making your pipelines more modular and easier to maintain.

‍Infrastructure-Agnostic Deployments: With GitLab, you can build flexible pipelines that can be deployed across various infrastructures, including virtual machines and Kubernetes clusters. GitLab also supports Google Cloud Platform, Amazon Web Services, and Microsoft Azure.

License

GitLab is published under an MIT open-source license.

G2 Rating

4.5 out of 5.

5. Harness

Harness is an all-in-one, open-source platform that lets you streamline the software development lifecycle. It brings together everything needed to host code, automate CI/CD, manage artifacts, and set up development environments. This enhances productivity and gives your team a cohesive environment for effective collaboration.

Key Features of Harness

Gitspaces: These are the ready-to-use remote development environments that eliminate the hassle of maintaining local development setups. These environments come pre-configured with everything you need to start coding, including dependencies, tools, and libraries.

‍Secure Code Repository: Harness provides a Git-based source code repository with integrated tools for code reviews and secret scanning on commits. It features built-in integration with Gitleaks, which helps prevent hard-coded secrets like passwords and API keys from entering your repository.

‍One-click Migrations: With just a single click, Harness enables you to automatically migrate code repositories and pipelines from GitLab, GitHub, Bitbucket, CircleCI, and more.

License

Harness is licensed under Apache 2.0.

G2 Rating

4.5 out of 5.

6. Buildbot

Buildbot is a Python-based continuous integration system for automating software build, test, and release processes. Unlike other CI tools that focus on predefined workflows, Buildbot provides a highly customizable framework to meet the unique needs of your project.

Key Features of Buildbot

Accelerated Builds: Buildbot enhances the build and testing process through distributed and parallel execution of jobs, improving efficiency and speed.

‍Integration with Version Control Systems: With Buildbot, you can integrate with popular version control systems like Git and Subversion. This facilitates the automatic triggering of builds based on code commits, ensuring that the latest changes are always tested and validated.

‍Build Sets: Buildbot enables you to organize builds into build sets, which represent a collection of builds that compile and test the same version of the source code. This feature helps track the overall success or failure of related builds.

License

Buildbot is licensed under the GNU General Public License v2.0.

G2 Rating

4.3 out of 5.

7. GoCD

GoCD is a CI/CD server that helps you automate software delivery. It supports parallel and sequential execution of tasks, empowering you to create complex workflows that can be easily visualized and managed. Furthermore, it offers an extensible plugin design that lets you integrate with various popular third-party tools and services.

Key Features of GoCD

Cloud Native Deployments: GoCD streamlines the CD workflow on popular cloud environments like Docker, Kubernetes, AWS, and more.

‍Analytics Plugin: The GoCD Analytics plugin provides insights into your GoCD instance. It gives real-time visibility into metrics like pipeline build times and wait times to optimize your software delivery process.

‍End-to-End Visualization: GoCD’s value stream map provides a comprehensive overview of your entire path to production in a single view. You can navigate across jobs, identify inefficiencies, and enhance your processes.

License

GoCD is available under the Apache 2.0 open-source license.

G2 Rating

4.1 out of 5.

8. Concourse CI

ConcourseCI is a continuous integration and delivery tool that helps you automate software delivery pipelines. It uses a pipeline-based approach, where each pipeline consists of jobs and resources for easy management of workflows.

Key Features of Concourse CI

Detailed Job Plans: Each job within a Concourse pipeline has a comprehensive build plan that outlines all job dependencies involved in execution.

‍Containerized Builds: Every task in Concourse runs in its own container, ensuring a clean and consistent environment for each build. This isolation helps prevent issues related to dependency conflicts.

‍Visual Pipeline Management: Concourse provides a user-friendly web UI that allows you to visualize your pipelines. Thus, you can quickly identify the status of jobs and troubleshoot failures.

License

Concourse is under the Apache License 2.0.

G2 Rating

4.1 out of 5.

9. Spinnaker

Spinnaker is a robust continuous delivery platform that helps you release software changes quickly and reliably. It complements CI tools such as Jenkins by orchestrating the entire deployment pipeline, such as invoking the CI tools, fetching the artifacts they create, and deploying the final package into the target environments.

Key Features of Spinnaker

Canary Analysis: Spinnaker includes built-in support for canary analysis, allowing you to deploy updates to a small subset of users and monitor performance before a full rollout.

‍Multi-Cloud Support: With Spinnaker, you can deploy applications across multiple cloud providers, such as Kubernetes, AWS EC2, OpenStack, Microsoft Azure, and more.

‍Role-Based Access Control: Access to projects can be restricted based on user roles by using various authentication systems like OAuth, SAML, LDAP, or Azure Groups.

License

Spinnaker is licensed under the Apache License 2.0.

G2 Rating

3.9 out of 5.

Features to Look Out for in Open-Source CI/CD Tools

Here are some of the key factors to consider when selecting the CI/CD open-source tools:

Ease of Use

Consider platforms that feature user-friendly dashboards and graphical representations of the pipelines. This minimizes the learning curve and enables you to understand and manage the workflows efficiently.

Scalability

Look for CI/CD solutions that provide the scalability to accommodate your growing needs. Features like parallel execution of jobs, distributed testing capabilities, and dynamic resource allocation are essential for optimal performance during heavy workloads.

Cross-platform and Language Support

Select tools that support multiple operating systems(e.g., Windows, Linux, macOS) and programming languages. This is particularly important if you're working with diverse tech stacks across projects.

Integration Capabilities

Make sure the platform enables you to integrate with your existing environment, like version control systems (e.g., Git), containerization platforms (e.g., Docker), and cloud providers (e.g., AWS, Azure). Additionally, ensure they offer a wide range of plugins and APIs for customization.

Security

Prioritize solutions that incorporate robust security solutions, such as role-based access control, encrypted data transfers, and comprehensive audit trails. These features safeguard your codebase from unauthorized access and ensure compliance with industry standards.

Open-Source CI/CD Tools: Which One Should You Pick?

Jenkins and Harness are the most popular tools, each catering to different needs and user bases.

Deployment Model

Jenkins: It is primarily available for on-premises deployment. While there are commercial offerings that provide Jenkins as a service, the core product requires self-hosting and management.‍

Harness: Offers both on-premises and SaaS options, making it more flexible for organizations that prefer not to manage their own infrastructure.

Ease of Use

Jenkins: Known for its flexibility, Jenkins can be complex to set up and maintain. It often requires significant scripting and plugin management, which can be a barrier for teams without dedicated DevOps resources.‍

Harness: Designed for ease of use, Harness allows you to set up pipelines quickly with minimal configuration. It incorporates declarative pipelines with minimal maintenance overhead.

Security

Jenkins: Jenkins does not provide built-in secrets management capabilities. You must rely on third-party providers like HashiCorp Vault or Helm Secrets.

‍Harness: Harness offers built-in secrets management. It offers robust security features like role-based access controls, encryption, and comprehensive audit trails.

Best Fit

Jenkins: Best suited for small to medium-sized teams with experienced DevOps engineers who require a highly customizable tool and are willing to invest time in setup and maintenance. It is ideal for organizations that have specific needs that can be met through its extensive plugin ecosystem.

‍Harness: Ideal for larger organizations or teams looking for a robust, easy-to-use solution that minimizes maintenance overhead. It is particularly well-suited for teams that prioritize rapid deployment and continuous verification, as well as those that may not have extensive DevOps expertise.

Conclusion

This article highlighted the key benefits of using CI/CD tools, such as improved efficiency, faster deployment cycles, and enhanced collaboration among development teams. You've also explored some of the best open-source CI/CD tools available, including Jenkins, GitLab, and Harness, each offering unique features to streamline development workflows.