Continuous integration (CI) is a development practice where developers frequently merge code changes into a shared repository, with each merge automatically triggering build and test pipelines.
How CI Works
Continuous integration automates the process of integrating code changes. When a developer pushes code to a shared repository, an automated pipeline triggers that:
Builds the application from source
Runs tests — unit tests, integration tests, and linting
Reports results — success or failure feedback on the pull request
This rapid feedback loop catches bugs early, before they compound with other changes.
CI for Infrastructure
CI isn't just for application code. Infrastructure as Code benefits from the same practices:
Terraform validate — check syntax and configuration validity
Terraform plan — preview infrastructure changes in pull requests
Policy checks — enforce security and compliance rules before apply
Module testing — validate Terraform modules against real infrastructure
Best Practices
Keep the CI pipeline fast — aim for under 10 minutes for feedback
Run tests on every pull request, not just on merge
Use branch protection rules to require passing CI before merge
Cache dependencies and build artifacts to speed up pipelines
Parallelize independent test suites
Popular CI Tools
GitHub Actions — integrated with GitHub repositories