Continuous Integration (CI)

Continuous Integration (CI) is the practice of frequently integrating code changes into a shared repository, with each integration triggering automated builds and tests. The goal is to detect errors early, reduce integration problems, and enable faster feedback.

CI is a cornerstone of high-performance DevOps and modern software delivery.

Level 1 – Initial (Ad Hoc)

Continuous Integration is not practiced consistently.
Developers may integrate code infrequently, often leading to integration hell, unstable builds, and delayed feedback.

  • Code changes are merged manually and sporadically
  • No automated build or test process
  • Integration happens late in the development cycle
  • Merge conflicts and defects are common and hard to trace

Level 2 – Managed (Emerging Practice)

CI tools (e.g. Jenkins, GitHub Actions, Azure DevOps) are in place for some teams, but adoption and discipline vary.
Builds may be automated but are not always reliable or enforced.

  • Automated builds triggered on some commits or manually
  • Unit tests may run automatically, but coverage is low
  • Developers often work on long-lived branches
  • Broken builds may go unnoticed or unfixed for extended periods

Level 3 – Defined (Standardised)

CI is standard practice across teams and integrated into the daily workflow.
All commits trigger automated builds and tests, with fast feedback loops and clear responsibilities for fixing failures.

  • All teams use CI pipelines with consistent standards
  • Builds are triggered on every commit to mainline branches
  • Tests are automated and required to pass before merge
  • Failures are visible and addressed quickly (build is sacred)
  • Branch strategies (e.g. trunk-based development) support frequent integration

Level 4 – Quantitatively Managed (Measured & Controlled)

CI performance is tracked and managed. Metrics are used to improve reliability and efficiency of integration workflows.

  • Metrics include build success rate, build duration, mean time to fix, and PR throughput
  • CI pipeline performance is monitored and optimised
  • Flaky tests are detected and addressed systematically
  • Developers receive feedback in under 10 minutes for common changes
  • Test coverage thresholds and quality gates are enforced

Level 5 – Optimising (Continuous Improvement)

CI practices are continuously improved through automation, experimentation, and systemic feedback.
They are deeply embedded in the culture and serve as a foundation for rapid delivery and learning.

  • CI pipelines evolve to reflect new needs (e.g. monorepos, microservices)
  • Builds are highly parallelised and optimised for developer experience
  • Intelligent test selection and incremental builds reduce feedback time
  • CI insights inform test strategy, deployment cadence, and team autonomy
  • Teams experiment with CI tooling, patterns, and observability to improve flow