Manage Monorepos for Scalable Development

Covers building and scaling a monorepo across three tool stacks: Turborepo (create-turbo scaffolding with an apps/packages layout, turbo.json pipeline definitions for build, test, lint, and dev, and remote caching via Vercel or a custom signed cache), Nx (create-nx-workspace scaffolding, generators for apps and libraries, nx.json target defaults with cacheable inputs, affected-only builds and tests, and dependency graph visualization), and pnpm workspaces (pnpm-workspace.yaml package globs, per-package dependency install, update, and remove via --filter, and parallel script execution across packages). Documents three code-sharing patterns with working TypeScript examples: shared UI components (a @repo/ui package exporting a Button component), shared utilities (@repo/utils string helpers like capitalize and truncate), and shared types (@repo/types User and CreateUserInput interfaces used on both frontend and backend). Adds shared configuration setup for TypeScript (a base tsconfig extended per framework) and ESLint (a shared preset extended per app), a GitHub Actions CI pipeline that installs with pnpm and builds, tests, lints, and type-checks through Turborepo, plus an example that deploys only apps affected by a change. Closes with a changesets-based publishing workflow (changeset init, changeset, version, publish, wired into a release GitHub Action) and named best practices - consistent versioning, centralized configs, acyclic dependency graphs, correct cache inputs and outputs, shared types, package-level unit tests versus app-level E2E, per-package READMEs - alongside common pitfalls: circular and phantom dependencies, incorrect cache inputs, over- or under-sharing code, and slow builds in large monorepos without proper tooling.

Use it when setting up a new monorepo, migrating from multiple repos into one, optimizing build and test performance, managing shared dependencies, implementing code-sharing strategies, setting up CI/CD for a monorepo, versioning and publishing packages, or debugging monorepo-specific issues. Skip it for anything unrelated to monorepo management or outside this scope.

Input is the target monorepo tool (Turborepo, Nx, or pnpm workspaces) and the task at hand - scaffolding, dependency management, caching, or CI; output is the matching configuration file (turbo.json, nx.json, pnpm-workspace.yaml), CLI commands, or code-sharing pattern, plus the best-practices and pitfalls lists to check the result against.

Package managers: pnpm workspaces (recommended), npm workspaces, Yarn workspaces. Build systems: Turborepo (recommended for most), Nx, and Lerna (noted as in maintenance mode). CI via GitHub Actions; publishing via Changesets; remote build caching via Vercel's Turborepo Remote Cache.

Teams setting up or scaling a monorepo who need concrete tool-specific configuration rather than abstract advice - from initial scaffolding through caching strategy, CI setup, and versioned package publishing.