What Is Trunk-Based Development?
Trunk-based development is a branching model where developers integrate small changes into a single shared branch, the trunk, very frequently.
Trunk-based development is a reaction against long-lived branches that drift apart and become painful to merge. By keeping everyone working close to the trunk and merging often, it makes integration cheap and continuous.
The core idea
There is one main branch, the trunk, that everyone integrates into. Developers either commit directly to it or use very short-lived branches that live for hours or a day, not weeks. Changes are kept small so they can merge quickly without large, conflict-prone diffs.
How it works
- Break work into small, independently shippable changes.
- Branch off the trunk only briefly, then merge back fast.
- Rely on CI to verify every merge into the trunk.
- Use feature flags to hide unfinished work in the trunk.
An example
A developer building a large feature does not work on a month-long branch. Instead they merge a small, flag-protected slice to the trunk each day. The feature is invisible to users until the flag is enabled, but the code is integrated and tested continuously, so there is never a giant merge.
Why it pairs with CI/CD
Trunk-based development and continuous integration reinforce each other. Frequent small merges only stay safe if every merge is automatically verified, which is exactly what CI provides. Keeping the trunk always releasable is also the precondition for continuous delivery and deployment.
Trade-offs
The model demands discipline: small changes, fast reviews, good tests, and feature flags for incomplete work. In exchange it avoids merge hell and keeps the codebase in a constantly shippable state, which is why high-performing teams favor it.
Key takeaways
- Trunk-based development keeps everyone integrating into one branch often.
- Branches are short-lived and changes are small.
- It depends on strong CI and feature flags to stay safe.