Trunk-based development is a software development workflow that keeps code integrated in one shared main branch through small, frequent changes. Developers commit directly to the trunk or use short-lived branches that are merged quickly. It supports continuous integration, but it requires reliable automated tests, fast reviews, and controls such as feature flags to keep unfinished work safe.
Trunk-Based Development
What Is Trunk-Based Development?
Trunk-based development is a workflow where developers integrate small, frequent code changes into one shared main branch, called the trunk. Main is the source of truth and should stay deploy-ready, while incomplete features can remain hidden behind feature flags.
How Trunk-Based Development Works
This workflow minimizes the time code changes stay separate from the application.
- Select a small, testable change.
- Update the local codebase from main.
- Create a short-lived branch only when pull request review is required.
- Run automated tests, linting, and build checks.
- Merge promptly after review and fix failed main-branch checks immediately.
- Deploy the change, or release it later behind a feature flag.
Benefits of Trunk-Based Development
Frequent integration makes delivery risks easier to identify while changes are small.
- Merge conflicts appear earlier, while the code is familiar.
- Small pull requests are faster to review.
- Automated feedback helps teams fix defects quickly.
- Release preparation is simpler because main stays near a releasable state.
- It supports continuous integration and continuous delivery.
Practical Limits and Challenges
This approach requires discipline and dependable automation. Frequent merging does not excuse a broken main branch.
- Tests must catch regressions, especially in critical code.
- Continuous integration pipelines must provide rapid feedback.
- Teams must split work into small, safe changes.
- Database migrations need backward-compatible planning while old and new code coexist.
- Feature flags need ownership and removal plans.
Trunk-Based Development vs GitFlow and GitHub Flow
GitHub Flow is similar but not always trunk-based development. The main difference is how quickly branches integrate into main.
| Workflow | Branch lifespan | Integration and releases | Best fit |
|---|---|---|---|
| Trunk-based development | Hours or a few days | Merge continuously; release from main or a narrow release branch | Teams with strong automated testing |
| GitHub Flow | Often short, but can vary | Merge reviewed feature branches into main; main is deployable | Teams using pull-request-based delivery |
| GitFlow | Long-lived feature, develop, and release branches | Integration often happens later through dedicated branches | Scheduled releases or legacy release processes |
Best Practices for a Healthy Main Branch
Healthy trunk-based development relies on consistent habits.
- Keep pull requests narrow and easy to review.
- Set a maximum lifetime for temporary branches.
- Require automated tests and proportionate review before merging.
- Use feature flags for unfinished user-facing work.
- Fix failed builds or production regressions quickly.
- Create release branches only for specific support needs.
Using Trunk-Based Development with Emergent
Emergent supports an agentic workflow for building, testing, and shipping full-stack applications, where small validated changes help maintain a reliable codebase. A clear spec-driven development process can define each change, while software development agents can support testing and delivery. Teams can also assess relevant AI tools for software development to strengthen feedback loops.
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