Continuous integration (CI) and continuous delivery (CD) are the unsung heroes that operate behind the scenes of every successful company.

CI is a software development practice where engineers merge their code into a central repository multiple times a day. After a pull request is open and after a merge is done, automated builds and tests are triggered automatically to ensure the functionality of the code. This approach promotes a collaborative environment and also helps in identifying issues early on, minimizing the risk of having issues propagated through different environments.

CD is the natural extension of CI, focusing on automating the deployment of the software updates that are done to designated environments after the CI builds and tests finish successfully. By minimizing manual interventions and automating the release process, CD helps organizations achieve quicker feedback loops and ensures the transition between environments and releases goes smoothly.

What are CI/CD tools?

CI/CD tools are specialized software applications that are designed to facilitate the practices of continuous integration and continuous delivery throughout the software development lifecycle (SDLC). These tools are responsible for managing the tasks associated with automated code integration, building, testing, packaging the code, and deploying the infrastructure/application code to various environments. By using CI/CD tools, development teams can easily streamline their workflows, detect and resolve issues quickly, and ensure the reliability of their software.

Note: The tools mentioned in the following sections are listed not in any order of preference.

1. Spacelift

Spacelift is a sophisticated infrastructure management solution that supports Terraform, OpenTofu, Terragrunt, Pulumi, CloudFormation, Ansible and Kubernetes workflows. It is specialized for infrastructure as code and provides a streamlined approach to CI/CD for it, simplifying the pipeline definitions and integrations with other tools.

Spacelift features

Key features include:

Flexibility: Bring your own image, control what happens before and after every runner phase, and integrate with any third-party tool you want.
VCS integration: Integrates with popular VCS providers such as GitHub, GitLab, BitBucket, and Azure DevOps.
Policies at multiple decision levels: You can control how many approvals you need for a run, what resources can be created, what parameters those resources can have, what happens when a pull request is open, and where to send your notifications data.
Cloud integrations: Dynamic temporary credentials for AWS, Azure, and GCP.
Drift detection and remediation: Ensures reliability of your infrastructure by detecting and remediating drift.
Contexts: Reusable Environment variables and Mounted files.
Self-service infrastructure with Blueprints: You can define infrastructure templates that can be easily deployed. These templates can have policies/integrations/contexts/drift detection embedded inside them for reliable deployment.
Stack Dependencies: Create dependencies between stacks and pass outputs from one to another. This can help to build an environment promotion pipeline easily.
Visibility: Easily see all the deployed resources and details about them.
Self-hosted capability: Spacelift can be self-hosted in AWS and AWS Gov Cloud.

See why DevOps Engineers recommend Spacelift.

2. Azure DevOps

Azure DevOps by Microsoft is an all-in-one CI/CD platform that features entire software delivery in one place. As the name suggests, it is more than just a CI/CD tool.

Azure DevOps features

Below are some of its key features:

Azure Repos - cloud-hosted private Git repository service.
Azure Boards - tracking and planning
Azure Pipelines - CI/CD automation. It can be integrated with any remote Git repository and not just Azure Repos. The extensions marketplace offers several pre-defined tasks that are reused along with custom tasks. The development of the CI/CD pipeline in Azure Pipelines follows an industry standard of YAML syntax. (Read more: Running Terraform with Azure DevOps CI/CD Pipelines)
Azure Artifacts - package management
Azure Test Plans - testing and quality assurance

What makes Azure DevOps stand out is its ability to wrap all of the above in a single window. Very few tools encompass the end-to-end software development lifecycle automation like Azure DevOps.

Considering the fact that a high percentage of organizations use Microsoft products and Azure for their office work, using Azure DevOps is a natural choice for CI/CD automation in large teams.

3. GitHub Actions

GitHub Actions is a feature-rich CI/CD platform embedded within GitHub, enabling developers to automate, customize, and execute software development workflows directly in their repositories. An Action inside GitHub Actions is a discrete unit of automation that performs a specific task within a workflow. All the Actions are reusable, and there are many to choose from. You can even create your own reusable ones.

With its event-driven approach, users can automatically trigger multiple tasks in response to specific GitHub events like pull requests or issues. These tasks vary from simple linting to complex building, testing, and deployment processes.

GitHub Actions features

Key features include:

Matrix builds (running tests on multiple versions and platforms simultaneously)
Caching
Shared storage between steps
Rich marketplace filled with community-contributed actions
Built-in Container Registry

By offering native integration with GitHub repositories, GitHub Actions streamlines the automation process and enhances the efficiency of code integration, testing, and deployment.

4. Jenkins

Jenkins is a highly extensible Java-based CI/CD automation server. It is open-source and self-hosted and enables you to automate, build, and deploy your software. The tool seamlessly integrates with various version control systems, cloud providers, and third-party applications, making it a versatile choice for modern development environments.

Jenkins features

Key features of Jenkins:

Rich set of plugins that integrate with every development, testing, and deployment tool in the industry
Simple UI
Built-in nodes for distributed builds across multiple machines
Robust pipeline-as-code approach using the Jenkinsfile (groovy-based pipelines)
Build schedules
Easy environment configurations

Being one of the oldest CI/CD tools in the market, Jenkins still has many advocates, but its popularity is slowly decreasing.

5. Buddy

Buddy CI/CD is an automation platform designed to streamline and accelerate software development and deployment processes. By emphasizing simplicity and efficiency, Buddy offers an intuitive UI that allows teams to set up, monitor, and execute pipelines with minimal friction.

Buddy features

Key features of Buddy:

Visual Pipeline Builder: Intuitive drag-and-drop interface for crafting CI/CD workflows
Docker layer caching: Faster build times by reusing Docker caching layers
Rich integrations: Can integrate with popular VCS, Cloud and Notification services
Self-hosted versions: Can be self-hosted
Atomic deployments: Ensures consistency by deploying only changed parts of the application
Parallelism: Runs tasks simultaneously or queues them for optimal resource utilization

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6. TeamCity

TeamCity is a robust CI/CD platform developed by JetBrains. It offers a comprehensive platform that ensures reliable and efficient software builds, tests, and deployments. Its flexibility, scalability, and integrations make it a top choice for teams aiming for an integrated development environment that adapts to complex project needs.

TeamCity features

Key features of TeamCity:

Creates sophisticated build pipelines with dependent and parallel builds
Analyzes code and provides feedback on potential issues without affecting the main build
Allows distributed builds and tests across multiple servers and agents
Offers numerous methods to reuse project settings in child projects
Allows flexible RBAC
Offers a live dashboard with build progress, statistics, and history

7. CircleCI

CircleCI is a leading cloud-native CI/CD platform that empowers developers to rapidly build, test, and deploy their applications at scale. It is highly configurable and has rich integrations and performance optimization tools. These features have made it a favorite among modern development teams seeking agility and speed.

CircleCI features

Key features of CircleCI:

Create sophisticated CI/CD pipelines with parallel, sequential, and manual job execution
Matrix Builds: Run tests across multiple versions and environments simultaneously
Orbs: Shareable and reusable packages of configuration to simplify pipeline creation and integration
Ability to customize CPU and RAM resources based on specific job requirements.
Access failing builds or workflows via SSH for real-time troubleshooting.
Easy debugging

8. AWS CodePipeline

AWS CodePipeline is a fully managed CI/CD service offered by AWS. It automates the build, test, and deployment features of your release process. It is designed to provide a seamless integration experience with other AWS services and popular third-party tools. AWS Code Pipeline ensures rapid and reliable application and infrastructure updates, empowering developers to iterate swiftly and maintain high software quality standards.

AWS CodePipeline features

Key features of AWS CodePipeline:

Seamless integration with services like AWS CodeBuild, AWS CodeDeploy, AWS Lambda, and more
Built-in encryption for artifacts; and integrates with AWS Key Management Service for enhanced security
Configure multiple actions to run simultaneously or in a specified order for efficient pipeline executions
Easily design and visualize your release process workflows

9. TravisCI

TravisCI is a cloud-based CI service that integrates seamlessly with GitHub repositories. After every new push or pull request, TravisCI will build and test the code according to the definitions made. It is well known for its simplicity and ease of setup.

Travis CI features

Key features of TravisCI:

Quick setup
Matrix builds (Simultaneously test applications across multiple runtime environments and configurations)
Caching mechanism
Deployment integrations
Docker support

10. GitLab CI/CD

GitLab CI/CD is an integrated feature of the GitLab VCS platform that automates the CI/CD workflow. With a unified experience that covers the entire SDLC, GitLab CI/CD facilitates swift iterations, robust testing, and reliable deployments, all within the GitLab environment. Its native CI/CD tools empower teams to deliver code changes faster and with increased confidence.

GitLab CI/CD features

Key features of GitLab CI/CD:

Detailed view of pipeline stages, jobs, and statuses for streamlined monitoring
Auto DevOps feature - automatically configures CI/CD based on best practices, reducing the manual setup process
Direct connection with Kubernetes for efficient application deployment and scaling
Built-in Container Registry - store and manage Docker images
Automatic security scans for vulnerabilities and compliance checks

11. BitBucket Pipelines

BitBucket Pipelines is Atlassian's contribution to CI/CD tools. It transforms Bitbucket repositories into fully-fledged CI/CD platforms, eliminating the need for third-party integrations. With a simple, configuration-as-code approach, it offers teams a unified platform for code collaboration and deployment automation.

BitBucket Pipelines features

Key features of BitBucket Pipelines:

Native integration with the Atlassian Stack (Jira, Confluence)
Accelerates build times by running steps or commands concurrently
Optimizes pipeline execution by caching dependencies and other data between builds
Defines and manages different environments like staging or production
Branch-specific configurations

12. Harness

Harness is a continuous delivery-as-a-service platform that offers many products and services under the same umbrella. It aims to provide a seamless, efficient, and intuitive experience that reduces the risks associated with releases, ensures faster time-to-market, and maximizes engineers' productivity.

Harness features

Key features of Harness:

Automated rollback in case of deployment failures, ensuring system stability
Reusable deployment templates to maintain consistency across applications and environments
Define and manage deployment pipelines using a version-controlled, codified approach
Supports multiple cloud providers, Kubernetes, and traditional infrastructure for deployment

13. Semaphore

Semaphore is a high-performance CI/CD platform designed for developers seeking speed and efficiency in their workflows. It establishes the CI/CD standards by leveraging the pull-request based development workflow.

Semaphore features

Key features of Semaphore:

Optimized for speed, offering fast feedback on code changes
Dynamic adjustment of resources based on workload, ensuring optimal performance
Execute multiple jobs simultaneously for accelerated build and test cycles
Control and manage the release of code from one environment to the next

How to choose the right CI/CD tool?

There is no right or wrong way to choose a CI/CD tool. Each tool has different strengths. Just as restaurants may excel at a few popular specialty dishes, no CI/CD tool can build, test, and deploy absolutely everything to the same level of excellence.

Spacelift specializes in infrastructure management, and it's one of the best choices available in this area. However, if your company develops a Java application and does maven or gradle builds, Spacelift will not be super helpful.

When choosing a CI/CD tool, you should consider the following:

what are you going to deploy
how much are you willing to spend
how much uptime you need
how it integrates with your existing tech stack
how customizable the tool needs to be
whether auto-scaling is important
how easy the tool is to learn
what the UI/UX is like

You need to consider many aspects, and evaluating multiple tools at the early stages makes a lot of sense.

Key points

In this post, we've reviewed the most popular CI/CD tools on the market and some best practices when it comes to choosing the right CI/CD tool for your needs. There are many tools in the DevOps ecosystem, and the ecosystem is constantly growing and improving, so choosing the right CI/CD tool can be hard if you don't evaluate it specifically for your use case.

Written by Sumeet Ninawe and Flavius Dinu.

Most Useful CI/CD Tools for DevOps