Trunk-Based Development Cheat Sheet

Trunk-based development — short-lived branches, daily merges to main, feature flags, and CI/CD practices for high-velocity teams.

Last Updated: May 1, 2025

Core Practices

Item	Description
`Short-Lived Branches`	Branches exist for hours, not days — merge to main at least daily
`Small Commits`	Each commit is small, atomic, and passes all tests
`Feature Flags`	Incomplete features ship to production behind toggles
`Comprehensive Testing`	Fast test suite runs on every commit before merge
`Code Review`	Every commit is reviewed — pair programming counts as review
`Continuous Deployment`	Main is always deployable — deploy multiple times per day
`No Long-Running Branches`	No develop, no release branches — just main
`Release Tags`	Tag specific commits on main for release identification

Branch Workflow

git checkout -b short-fix main

Create very short-lived branch from main

git commit -m 'Fix: correct validation logic'

Small, focused commit

git fetch origin main && git rebase origin/main

Rebase on latest main before merging

git push -u origin short-fix

Push and open PR immediately

gh pr create --fill

Create PR with auto-filled description

gh pr merge --squash --delete-branch

Squash merge and clean up branch

git checkout main && git pull

Update local main after merge

git branch -d short-fix

Clean up local branch

Feature Flags

Item	Description
`Launch Darkly`	Managed feature flag service with targeting and analytics
`Environment Variables`	Simple flags via env vars: FEATURE_NEW_UI=true
`Config File Flags`	YAML/JSON config flags for moderate complexity
`Trunk-Based + Flags`	Ship code immediately; enable feature when ready
`A/B Testing`	Use flags to roll out features to percentage of users
`Kill Switches`	Emergency flags to disable features without redeploying
`Flag Cleanup`	Remove flag code after feature is fully rolled out and stable
`Operators`	Per-team, per-user, percentage-based, and date-scheduled rollouts

TBD vs Other Models

Aspect	Trunk-Based	GitHub Flow	GitFlow
Branch Lifespan	Hours	Days	Weeks to months
Main Branches	1 (main)	1 (main)	2 (main + develop)
Release Cadence	Continuous	Continuous	Scheduled
Merge Frequency	Daily+	Every few days	When feature complete
Complexity	Low	Low	High
Best For	CI/CD, DevOps	Web apps, SaaS	Mobile, packaged software

Pro Tip: The key to TBD is small, frequent merges. If your branches live more than a day, you're doing it wrong. Pair with feature flags for incomplete work.