CI/CD for Monorepos 2026: Build Only What Changed
TL;DR: A monorepo with naive CI rebuilds the world on every commit, so pipelines get slower exactly as the repo succeeds. The fix is affected-only delivery: detect what changed, expand through the dependency graph, build and test only that slice, lean on remote caching for the rest, and protect the main branch with required checks plus a merge queue. Start with path filters in GitHub Actions;…
Monorepos with naive CI rebuild the entire codebase on every commit, causing pipelines to slow down as the repository grows. The solution is affected-only delivery, which detects what has changed, expands through the dependency graph, and builds and tests only the affected slice. Remote caching is utilized for the rest, while the main branch is protected with required checks and a merge queue.
Start with path filters in GitHub Actions and graduate to a build tool like Nx, Turborepo, or Bazel when the graph becomes too complex for filters. The core idea is to implement four steps: detect changed files, map them to owning projects, expand through the dependency graph, and execute builds, tests, and deploys for the affected set only.
Path filters in GitHub Actions provide a starting point for many teams, but for deeper graph complexity, a build tool should own the graph, with caching being the second crucial step.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.