Continuous Integration
Definition
A software development practice where developers frequently merge code changes into a shared repository, with each change automatically built and tested.
Use Cases
- Netflix: Validate microservice changes quickly to reduce production risk — Engineers use automated build and test pipelines that run on every change, including unit tests and integration checks, before changes are promoted through later delivery stages. (Faster feedback to developers, fewer regressions reaching later stages, and safer high-frequency releases.)
- Etsy: Ship frequent website and backend updates while maintaining reliability — Teams rely on automated testing and build verification on each change so issues are detected early, before code is merged or released. (Shorter lead time from code to production and improved stability through early defect detection.)
- Google: Keep large codebases stable while many developers commit changes continuously — Uses extensive automated builds and tests (including presubmit checks) to validate changes early and prevent breaking shared mainline code. (Higher confidence in mainline stability and faster iteration by catching failures close to the change that introduced them.)
Provider Equivalents
- AWS: AWS CodeBuild
- Azure: Azure Pipelines
- GCP: Cloud Build
- OCI: OCI DevOps (Build Pipelines)
Frequently Asked Questions
- What's the difference between Continuous Integration and Continuous Delivery (CD)?
- Continuous Integration (CI) is about automatically building and testing every change as developers merge code into a shared branch. Continuous Delivery (CD) goes further by automatically preparing and promoting those validated changes so they are always in a deployable state (and may deploy automatically depending on your process). In short: CI proves the code works; CD automates getting proven code ready to release.
- When should I use Continuous Integration?
- Use CI when multiple people contribute to the same codebase, when you want fast feedback on pull requests, or when regressions are costly. CI is especially valuable for microservices, APIs, mobile apps, and infrastructure-as-code because automated checks (tests, linting, security scans) catch issues early and reduce time spent debugging broken builds later.
- How much does Continuous Integration cost?
- CI cost mainly depends on build minutes, compute size, and how often pipelines run. Common cost drivers include: number of commits/PRs triggering builds, parallel jobs, use of larger CPU/RAM or GPU runners, time spent running tests, and artifact storage (build outputs, logs). Managed CI services typically charge per build minute (or per runner time) plus any underlying storage/network usage; self-hosted runners shift cost to your own compute and operations time.
Category: devops
Difficulty: intermediate
Related Terms
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