NX Monorepo Guide - Introduction & Architecture

Welcome to Part 1 of our NX Monorepo series! In this guide, we'll explore the foundational concepts and architectural patterns for building scalable fullstack monorepos. Part 2 will be a hands-on walkthrough where we build a complete working repository from scratch.

The Repository Strategy Decision

When managing multiple related projects, teams typically choose between two strategies:

Polyrepo (separate repositories): Each project lives in its own repository with independent versioning, CI/CD, and release cycles. It's easy for new learner and small teams to get started.

Monorepo (single repository): All related projects share one repository, enabling code sharing and atomic changes across the entire codebase.

Companies like Google, Meta, Microsoft, and many others use monorepos to manage their massive codebases. But monorepos aren't just for big tech—they're increasingly popular for teams of all sizes.

Why Choose a Monorepo?

The Problem: Monorepos Without Proper Tooling

Simply putting all your code in one repository (code collocation) isn't enough. Without proper tooling, monorepos become painful:

This is why many teams abandon monorepos—not because monorepos are bad, but because they lacked the right tools.

Enter NX: Making Monorepos Work at Scale

NX was created to solve these exact problems. It transforms a simple code collocation into a true monorepo with intelligent tooling:

How NX Solves Each Challenge:

1. Task Caching — Never rebuild unchanged code

• NX caches the output of every task (build, test, lint)
• If inputs haven't changed, NX restores from cache instantly
• With NX Cloud, cache is shared across your entire team and CI

2. Affected Commands — Only run what's needed

• NX analyzes your code changes and dependency graph
• Only affected projects are rebuilt, tested, or linted
• A small change doesn't trigger a full repo rebuild

3. Module Boundaries — Enforce architectural rules

• Define which projects can depend on which
• ESLint rules prevent unauthorized imports
• Keep your architecture clean as the codebase grows

4. Dependency Graph — Understand your codebase

• Visualize project relationships with nx graph
• Understand the impact of changes before making them
• Identify circular dependencies and architectural issues

5. Consistent Tooling — Plugins and Generators

• Standardized commands across all projects
• Generators create new projects with best practices built-in
• Plugins provide framework-specific optimizations