Build Cache Strategy: Bazel, Nx, Turborepo Compared

Build caches turn monorepo CI from minutes to seconds. The tool you pick determines your ceiling.

Why build cache matters

Without a build cache, every CI run rebuilds everything. The cost compounds with monorepo size; the savings from caching are dramatic at scale.

• Without cache. Every CI run rebuilds the world; the cost grows linearly with the codebase.
• With cache. Only changed code rebuilds; the rest is fetched from cache in seconds.
• Scale impact. At meaningful monorepo size, the difference is 30 minutes versus 30 seconds.
• Compounding velocity. Every PR benefits; the savings show up in cycle time across the whole team.

Bazel: hermetic and rigorous

• Bazel: hermetic builds; remote cache; remote execution; works for any language.
• High setup cost; high payoff at scale; steep learning curve.

Nx: pragmatic JS/TS focus

Nx is the JavaScript and TypeScript ergonomic choice. Affected-graph computation plus cloud cache cover most web monorepo needs without Bazel's setup cost.

• JS/TS-first. Designed for the JavaScript and TypeScript ecosystem; integrates with the existing tooling.
• Affected graph. Computes which packages need rebuilding from the diff; minimises wasted work.
• Nx Cloud. Hosted cache option; pay for it or self-host; saves the platform team from running cache infrastructure.
• Less ambitious than Bazel. Does not aim for hermetic builds; faster to adopt, lower ceiling.

Turborepo: lightweight default

Turborepo is the easiest option to onboard. Lightweight, quick to set up, shared cache via Vercel; the right choice for small-to-mid teams.

• Lightweight. Minimal config; sensible defaults; one config file in the repo root.
• Quick setup. Hours to a working build cache; versus days for Nx, weeks for Bazel.
• Vercel integration. Shared cache via Vercel's cloud; no self-hosted infrastructure required.
• Scale ceiling. Less powerful than Bazel or Nx at scale; revisit when the monorepo grows past mid-size.

Antipatterns

• Bazel for a 5-package repo. Overkill.
• No remote cache. CI rebuilds everything per run.
• Mixing tools across the same repo. Configuration nightmare.

What to do this week

Three moves. (1) Apply this to one pipeline first. (2) Measure deploy frequency / MTTR before/after. (3) Document the outcome so the next team starts from data.