Ever wondered why some development teams ship code daily while others struggle with monthly releases? Trunk based development might be the answer. This streamlined approach to source control management has transformed how leading tech companies like Google and Facebook build software.
In essence, trunk based development is a branching strategy where developers integrate their work frequently into a single main branch (called ‘trunk’). Unlike complex methodologies that use multiple long-lived branches, this approach prioritizes small, regular commits to maintain a single source of truth.
The benefits are compelling: faster feedback loops, reduced merge conflicts, and improved team collaboration. Whether you’re using Git, Subversion (SVN), or other version control systems, the principles remain the same.
This guide explores everything you need to know about trunk based development—from basic workflows to implementation strategies. You’ll learn how it compares to GitFlow and GitHub Flow, and why it forms the foundation for effective continuous integration and deployment pipelines.
What Is Trunk Based Development?
Trunk Based Development is a software development approach where all developers commit code to a single branch, often called “main” or “trunk.” Changes are small, frequent, and integrated continuously, reducing merge conflicts and encouraging collaboration. It’s popular in continuous integration environments for maintaining a fast, stable release cycle.
How Trunk Based Development Works
Trunk Based Development represents a source control management approach where developers collaborate on code in a single branch called ‘trunk’ (or ‘main’ in Git). Unlike complex branching strategies, it focuses on simplicity and frequent integration.
The Basic Workflow
The workflow centers around making small batch changes to the codebase. Developers work locally, test thoroughly, then integrate quickly back to the main branch. This creates a single source of truth that keeps everyone synchronized.
Here’s how it typically works:
- Make small, focused code changes on your local machine
- Run automated testing to verify your changes work correctly
- Pull recent changes from the trunk to stay current
- Resolve any conflicts that appear (they’re usually minor due to frequent integration)
- Push your changes to the main branch quickly
Conflicts happen less often than you might think. Since everyone commits frequently to the shared codebase, changes rarely diverge significantly. When conflicts do occur, they’re smaller and easier to resolve than in feature branch development approaches.
Two Main Implementation Approaches
Teams adopt Trunk Based Development in one of two ways, depending on their size and needs:
Direct-to-trunk Commits
Small, cohesive teams often commit directly to the trunk. This approach:
- Works best with 3-8 developers
- Requires strong team collaboration and communication
- Demands excellent test-driven development practices
- Relies on deep code ownership across the team
The direct approach keeps the development workflow extremely simple. Teams using pair programming often prefer this method since code is already reviewed during pairing sessions.
Short-lived Feature Branches
Larger teams typically use short-lived branches with pull requests. These branches:
- Last no more than 1-2 days
- Focus on discrete functionality
- Get reviewed quickly through the code review process
- Merge back to trunk immediately after approval
Companies like Google and Facebook use this approach at scale. The key difference from other branching strategies is the emphasis on keeping branches extremely short-lived, usually hours rather than days or weeks.
Tools That Support This Approach
Several tools make Trunk Based Development more effective:
- Version control systems like Git, Perforce, or Subversion (SVN)
- CI/CD pipeline tools such as Jenkins, CircleCI, or Travis CI
- Testing frameworks that support fast, reliable automated testing
- Feature flags management systems like LaunchDarkly
GitHub and GitLab offer built-in features that align perfectly with trunk-based workflows, making them popular choices for teams implementing this approach.
Key Benefits of Trunk Based Development
Faster Development Cycles
Trunk Based Development dramatically speeds up the development process. By integrating frequently, teams eliminate wait states and bottlenecks.
Consider this: when developers work on long-lived branches, they often wait days or weeks before merging. This leads to painful merge conflicts and delays. Trunk-based teams integrate multiple times daily, keeping the deployment pipeline flowing smoothly.
The State of DevOps Report consistently shows that high-performing teams use this approach to achieve superior deployment frequency and team productivity.
Better Code Quality Through Frequent Integration
Continuous integration is more than a tool. It’s a practice that improves code quality through rapid feedback.
When you commit to trunk frequently:
- Bugs get caught earlier through continuous integration
- Problems stay small and isolated
- Technical debt becomes visible quickly
- The mainline development branch remains stable
The DORA (DevOps Research and Assessment) metrics show that organizations using Trunk Based Development achieve better stability and lower change failure rates.
Support for Continuous Integration and Delivery
You can’t truly implement CI/CD pipeline practices without trunk-based workflows. The two approaches complement each other perfectly:
- Trunk Based Development ensures code is integrated continuously
- Continuous delivery enables rapid, reliable releases
- Together, they create a fast feedback loop for development
Authors like Jez Humble in the book Accelerate have documented how this approach enables the highest levels of software delivery performance.
Improved Team Collaboration
Perhaps the most important benefit is how Trunk Based Development transforms team dynamics. It creates:
- Shared codebase ownership instead of siloed knowledge
- A transparent development process visible to everyone
- Easier knowledge sharing across specialties
- Better alignment with agile methodology
Teams at Spotify and Microsoft have documented how this approach improves collaboration and breaks down silos between development groups.
With everyone working from the same recent version of the codebase, collaboration becomes much easier. Questions about “which version are you using?” disappear completely.
Code Organization and Visibility
Trunk Based Development creates clear codebase organization. Since everything lives in a single branch, there’s no confusion about where to find the latest code.
This approach pairs well with a monorepo strategy used by companies like Google. Their massive codebase houses thousands of projects in a single repository, making cross-team collaboration seamless.
Expert practitioners like Martin Fowler from ThoughtWorks have written extensively about how this approach creates more maintainable systems with better code stability over time.
For teams seeking to improve their development speed while maintaining quality, Trunk Based Development offers a proven path forward.
Common Techniques Used With Trunk Based Development
Trunk Based Development works best when paired with specific practices that enable teams to move quickly while maintaining code stability. These techniques solve common challenges in the development process.
Feature Flags/Toggles
Feature flags are conditional statements in code that control whether functionality is visible to users. They’re essential to trunk-based development.
How they work:
- New code enters the main branch behind a disabled flag
- Code remains inactive in production until ready
- When complete, the flag is switched on, revealing the feature
- After full deployment, flag code is removed in a cleanup commit
Companies like Facebook and Microsoft use thousands of feature flags to manage their massive codebases. Tools from providers like LaunchDarkly help teams implement flags at scale.
Feature toggles solve a critical problem: they separate deployment from release. This gives teams the freedom to commit code frequently without exposing unfinished work to users.
The best teams manage flags carefully:
- Document each flag’s purpose
- Set clear expiration criteria
- Regularly clean up old flags
- Test both flag states (on/off)
This pattern enables continuous integration while protecting users from incomplete features.
Branch by Abstraction
Sometimes changes are too big for a single commit. Branch by abstraction is the solution.
This technique involves:
- Create an abstraction layer over the code you need to replace
- Build the new implementation behind this abstraction
- Gradually switch components to use the new implementation
- Remove the old implementation when no longer needed
This approach maintains code quality while enabling large-scale rewrites. Martin Fowler from ThoughtWorks has documented this pattern extensively.
A key benefit is risk reduction. Each step is small and reversible. If problems occur, you can easily roll back without disrupting the entire system.
Test-Driven Development
TDD perfectly complements trunk-based workflows. Write tests first, then code until they pass.
The process looks like:
- Write a failing test describing desired behavior
- Implement just enough code to make the test pass
- Refactor for cleanliness without changing behavior
- Commit to trunk when the cycle completes
This creates a safety net for the shared codebase. When everyone follows TDD, the main branch remains stable even with frequent commits.
Automated testing becomes increasingly important as teams scale. Google famously runs millions of tests daily to protect their monorepo.
Pair Programming and Code Reviews
Two techniques ensure code quality when working on the trunk:
Pair programming involves two developers working together at one workstation. One writes code while the other reviews in real-time. This creates:
- Instant feedback
- Knowledge sharing
- Fewer bugs through continuous review
- Shared context across the team
For teams using short-lived branches, pull requests provide similar benefits:
- Quick, focused code reviews
- Knowledge sharing through comments
- Documentation of design decisions
- Distributed team collaboration
Stack Overflow and many other tech companies rely heavily on code reviews to maintain quality in their trunk-based workflows.
Trunk Based Development vs. Other Branching Strategies
Comparison with Git Flow
Git Flow represents almost the opposite philosophy from trunk-based development. It uses multiple long-lived branches for different purposes.
Key differences:
- Git Flow maintains at least two permanent branches (main and develop)
- Features, releases, and hotfixes get dedicated branches
- Integration happens less frequently, usually at release boundaries
- Releases require complex merging between branches
When might Git Flow make sense?
- Teams supporting multiple released versions simultaneously
- Software with formal release cycles (like desktop applications)
- Regulated environments with extensive release approval processes
The transition from Git Flow to trunk-based development usually involves:
- Shortening feature branch lifespans
- Implementing feature flags for incomplete work
- Building stronger automated testing capabilities
- Gradually reducing the number of long-lived branches
Comparison with GitHub Flow
GitHub Flow sits somewhere between trunk-based and Git Flow approaches.
Similarities with trunk-based development:
- Single primary branch (main)
- Emphasis on frequent integration
- Use of pull requests for code review
Key differences:
- GitHub Flow branches often live longer than true trunk-based branches
- Deployment typically happens after merge to main, not before
- Less emphasis on feature toggles to hide incomplete work
This approach works well for web applications with continuous deployment. Teams at Atlassian and many open source projects use variants of this workflow.
The boundary between short-lived feature branches in trunk-based development and GitHub Flow is sometimes blurry. The key difference is branch lifetime: hours vs. days or weeks.
Comparison with Feature Branch Development
Traditional feature branch development keeps changes isolated until complete. This creates several challenges that trunk-based development addresses.
How they differ:
- Feature branches often live for weeks or months vs. hours in trunk-based
- Integration happens at the end of development rather than continuously
- Merge conflicts are typically larger and more complex
- Team collaboration is hindered by code isolation
The Accelerate book by the DevOps Research and Assessment (DORA) team found that feature branching correlates with lower performance in software development lifecycle metrics.
Feature branches do provide some benefits:
- Clearer separation of work in progress
- Easier to stop and restart work
- Simpler conceptual model for beginners
However, these benefits often don’t outweigh the integration costs as teams scale. The continuous integration benefits of trunk-based development typically lead to better outcomes in the long run.
Impact on Team Communication
Different branching strategies fundamentally change how teams communicate:
- Feature branches tend to reduce communication until integration time
- Git Flow formalizes communication around releases
- Trunk-based development requires constant, lightweight communication
Teams using trunk-based development often adopt tools and practices that support this communication style:
- Team chat tools with code integration
- Visible build automation status dashboards
- Regular, brief synchronization meetings
- Cross-functional teams with shared code ownership
The Agile Alliance has documented how trunk-based development aligns more closely with agile principles than branching strategies that isolate work for longer periods.
For most modern software teams focused on continuous delivery, trunk-based development offers the best balance of speed, quality, and collaboration. Companies following this approach consistently outperform peers in development speed and release cadence according to industry benchmarks.
Best Practices for Trunk Based Development
Successful trunk-based development requires thoughtful practices and infrastructure. Teams must establish clear patterns that enable rapid, confident delivery.
Setting Up Effective Continuous Integration
The foundation of trunk-based development is a reliable CI/CD pipeline. Without it, the approach falls apart quickly.
Key requirements:
- Build automation that runs in under 10 minutes
- Test suites that deliver reliable results
- Immediate feedback on build failures
- Clear ownership of pipeline maintenance
Tools like Jenkins, CircleCI, and Travis CI support this workflow well. The critical factor isn’t which tool you choose but how you configure it.
Fast builds matter enormously. When continuous integration takes too long, developers create workarounds that undermine the process. Invest in build infrastructure that runs quickly, even as your codebase grows.
Most successful implementations include:
- Parallel test execution
- Distributed build systems
- Caching of dependencies
- Selective testing based on changed files
Google runs millions of tests daily across thousands of changes while maintaining fast feedback loops. Their approach demonstrates that trunk-based development scales when properly supported.
Creating a Strong Testing Strategy
Testing becomes even more critical in trunk-based workflows. With code integrating continuously to the main branch, tests are your safety net.
Effective testing strategies include:
Unit Tests
- Cover core business logic thoroughly
- Run in milliseconds, not seconds
- Execute with every commit
- Maintain at least 80% coverage of critical paths
Integration Tests
- Verify components work together correctly
- Target key user journeys
- Run slightly less frequently than unit tests
- Focus on boundaries between systems
Performance and Security Testing
- Scheduled runs rather than per-commit
- Baseline comparison to detect regressions
- Clear thresholds for acceptable changes
- Automated reporting of issues
Test-driven development aligns perfectly with trunk-based approaches. Many teams practicing trunk-based development report that their test automation improves dramatically over time.
Establishing Team Agreements
Technical practices aren’t enough. Teams need clear agreements about how they’ll work together.
Critical agreements include:
Code Standards
- Automated formatting (eliminating style debates)
- Static analysis rules with team consensus
- Documentation requirements for public APIs
- Performance expectations for critical paths
Communication Around Breaking Changes
- How much notice is required
- Communication channels for announcements
- Support periods for deprecated interfaces
- Rollback procedures when needed
Handling Production Issues
- Clear definition of severity levels
- Response time expectations
- Hotfix processes that preserve quality
- Post-mortem requirements
Teams at Microsoft and Atlassian document these agreements explicitly and review them regularly. This creates consistency even as team members change over time.
Managing Dependencies and External Code
External dependencies bring their own challenges to trunk-based workflows.
Best practices include:
- Clearly defined process for adding new dependencies
- Regular updates scheduled in the work cycle
- Automated vulnerability scanning
- Dedicated owners for critical dependencies
Many teams create “update days” when they systematically review and upgrade external packages. This prevents dependencies from falling too far behind, which can lead to painful integration later.
Versioning strategies should be explicit as well. Teams practicing trunk-based development typically prefer:
- Semantic versioning for released components
- Internal APIs versioned by date or build number
- Feature flags for managing compatibility
- Clear deprecation paths for internal consumers
Package managers like npm, Maven, and Gradle can help manage these dependencies systematically when properly configured.
Implementing Trunk Based Development
Transitioning to trunk-based development requires planning and incremental change. Most successful adoptions follow a clear path.
Starting Small with a Pilot Project
Don’t try to convert your entire organization at once. Start with a single team on a well-defined project.
Ideal pilot characteristics:
- Small team (3-7 developers)
- Modernized codebase with good test coverage
- Relatively independent from other systems
- Team members open to process changes
Set explicit goals for the pilot:
- Specific metrics to improve (deploy frequency, lead time)
- Timeline for evaluation (usually 2-3 months)
- Regular retrospectives to adjust course
- Clear criteria for success or failure
Companies like Spotify often use this approach when introducing new development workflow patterns. They create small, focused teams to validate approaches before scaling them.
Scaling to Larger Teams
Once your pilot shows promise, expanding to larger groups requires additional infrastructure.
Focus areas for scaling:
Build Infrastructure
- Investing in faster, more reliable build systems
- Adding capacity for parallel testing
- Creating visibility tools for build status
- Implementing smart test selection
Team Training
- Documentation of core practices
- Pairing experienced developers with newcomers
- Regular knowledge-sharing sessions
- Clear escalation paths for questions
Progress Monitoring
- Dashboards showing key metrics
- Regular reviews of process adherence
- Identification of common friction points
- Celebration of successful patterns
The DevOps Research and Assessment (DORA) metrics provide an excellent framework for tracking progress: deployment frequency, lead time, change failure rate, and time to restore service.
Handling Common Challenges
Several challenges predictably emerge as teams adopt trunk-based development:
Breaking Up Large Changes
Large changes are the enemy of trunk-based development. Techniques to handle them include:
- Branch by abstraction for system rewrites
- Feature flags for major UI changes
- Incremental schema migrations for database changes
- Parallel implementations with routing between versions
Stack Overflow has published extensive case studies on how they handle large-scale refactoring while maintaining their continuous deployment flow.
Managing Long-Running Features
Sometimes features take weeks to complete. Handle these with:
- Decomposition into smaller, independently valuable pieces
- Feature toggles for hiding work in progress
- Clear interfaces between new and existing code
- Regular integration of partially completed work
This approach maintains development speed while preventing long-lived branches from forming.
Working with Legacy Code
Legacy systems often lack the automated testing needed for confident trunk-based development. Address this incrementally:
- Add characterization tests that document current behavior
- Create safe zones within the codebase with better coverage
- Gradually expand test coverage with each change
- Use more manual testing and longer stabilization for critical areas
The key is not waiting for perfect conditions before starting. Begin where you can and expand gradually.
Tools and Infrastructure Considerations
Specific tooling choices make trunk-based development easier to implement.
Version Control Setup
- Git configurations that support frequent commits
- Repository management tools that enable access control
- Branch protection for the main trunk
- Automated merge policies
Build and Test Automation
- Fast-running test suites (minutes, not hours)
- Reliable test environments that match production
- Parallelization of test execution
- Clear reporting of test failures
Deployment Pipelines
- Infrastructure as code for consistency
- Automated deployment to staging environments
- Simple, reliable rollback mechanisms
- Incremental deployment capabilities (blue/green, canary)
Teams at Facebook and Google have created custom internal tools to support their massive scale, but commercial and open-source options like GitHub, GitLab, and Bitbucket provide excellent support for trunk-based workflows.
The Continuous Delivery Foundation offers resources and case studies for teams implementing these practices. Their research consistently shows that trunk-based development, combined with strong technical practices, leads to better outcomes across all key delivery metrics.
For teams just starting their journey, focus on the fundamentals: small commits, thorough testing, and frequent integration. As these practices mature, the more advanced techniques will follow naturally.
FAQ on Trunk Based Development
What exactly is trunk based development?
Trunk based development is a version control practice where developers integrate code changes directly into a single branch called “trunk” or “main.” It emphasizes small, frequent commits rather than long-lived feature branches. This approach creates a single source of truth for the codebase and supports continuous integration by ensuring all developers work from the most recent code.
How does trunk based development differ from GitFlow?
Unlike GitFlow with its multiple long-lived branches (develop, release, feature), trunk based development uses just one primary branch. GitFlow isolates changes for longer periods, creating larger merge conflicts. Trunk based focuses on integrating small changes frequently, typically multiple times daily. It prioritizes continuous delivery over structured release cycles that GitHub Flow and GitFlow enforce.
Do I need feature flags for trunk based development?
Yes, feature flags are essential for trunk based development in production environments. They allow incomplete features to be merged into the main branch without affecting users. Teams at Facebook and Google heavily rely on flags to separate deployment from release, enabling continuous integration while protecting the user experience from work-in-progress features.
Is trunk based development suitable for small teams?
Small teams often benefit most from trunk based development. With fewer developers, the direct-to-trunk approach works exceptionally well. Less coordination overhead means faster development speed. Small teams using practices like pair programming and strong automated testing can ship multiple times daily with this approach, achieving excellent team productivity without complex branching.
How do you handle large features in trunk based development?
Large features require breaking work into smaller, independent chunks that can be integrated separately. Techniques like branch by abstraction and feature toggles allow developers to commit incremental changes while keeping unfinished work hidden from users. Google and other companies use these patterns to make even massive changes through small, safe steps.
Does trunk based development require more testing?
Yes, robust test automation is non-negotiable for trunk based development. Since code integrates directly to the shared codebase, strong testing prevents breaking changes. Test-driven development pairs naturally with this approach. Teams need comprehensive unit, integration, and system tests that run quickly in the CI/CD pipeline to provide fast feedback on changes.
How does code review work with trunk based development?
Code reviews happen either through pair programming (real-time review) or via short-lived feature branches with pull requests. The key difference from other approaches is speed: reviews must complete within hours, not days. Companies like Stack Overflow and Atlassian maintain high code quality through rapid, focused reviews that don’t delay integration.
Can trunk based development work with remote teams?
Yes, distributed teams successfully use trunk based development with the right practices. Remote teams typically rely more on short-lived feature branches with pull requests rather than direct trunk commits. Tools from GitHub, GitLab, or Bitbucket provide the necessary infrastructure. Clear communication channels and strong team collaboration tools become especially important in distributed environments.
What metrics improve with trunk based development?
The DevOps Research and Assessment (DORA) metrics typically show dramatic improvements: deployment frequency increases, lead time decreases, change failure rate drops, and time to restore service improves. Teams also see better code maintainability, reduced integration problems, and faster feedback loops. The State of DevOps Report consistently links trunk based development to high performance.
How do you start implementing trunk based development?
Start with a small pilot team working on a well-contained codebase with good test coverage. Focus first on shortening branch lifetimes to less than a day. Invest in build automation and test infrastructure. Implement feature flags for hiding incomplete work. The Continuous Delivery Foundation recommends measuring baseline metrics before starting to track improvements over time.
Conclusion
Understanding what trunk-based development is transforms how teams approach software creation. By focusing on small batch changes and incremental development, this methodology enables the high-velocity delivery that modern software demands. Companies like Microsoft and Spotify have demonstrated that this approach scales from startup teams to enterprise organizations.
The core benefits make a compelling case for adoption:
- Dramatically reduced integration testing complications
- Increased development speed through elimination of branching overhead
- Better code visibility across the entire team
- Strong foundation for implementing DevOps practices
While the transition requires investment in build automation and a shift in team mindset, the payoff is substantial. Teams using trunk based development consistently rank higher in DORA metrics than those using complex branching strategies.
For most organizations seeking to improve their software delivery, trunk based development offers the clearest path to success. Whether you’re using Perforce, Git, or other tools, the principles remain the same: integrate frequently, test thoroughly, and deploy confidently.
With over a decade in the tech field, Bogdan blends technical expertise with insights on business innovation in technology.
A regular contributor to TMS Outsource's blog, where you'll find sharp analyses on software development, tech business strategies, and global tech dynamics.
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