How the Pieces Fit
The three concepts — hermeticity, the dependency graph, and remote caching/execution — are not independent features. They form a stack where each layer depends on the one below it:
Without hermeticity, caching is unsafe (you might serve a stale artifact). Without the dependency graph, you cannot know what to cache or skip. Without caching, remote execution is still fast but wasteful. Together, they produce a system where build time scales with the size of your change, not the size of your codebase.
When to Adopt These Tools
Bazel and similar tools have a real adoption cost: BUILD files must be written and maintained, toolchain configuration is complex, and the learning curve is steep. The payoff is worth it when:
- Your monorepo build takes more than 10-15 minutes in CI.
- You have multiple languages that need to interoperate at build time.
- You have more than ~50 engineers committing to the same repository.
- Flaky, environment-dependent builds are causing significant developer friction.
For smaller teams or polyrepo setups, simpler tools (GitHub Actions caching, Docker layer caching, turborepo for JS monorepos) often provide 80% of the benefit at 20% of the complexity cost. Choosing the right tool for your scale is itself a senior engineering judgment.