# .github/workflows/ci.yml on: [push] jobs: test-changed-modules: runs-on: ubuntu-latest steps: - uses: dorny/paths-filter@v3 id: filter with: filters: | invoice-service: - 'services/invoice-service/**' billing-models: - 'packages/billing-models/**' - name: Test Invoice Service if: steps.filter.outputs.invoice-service == 'true' run: cd services/invoice-service && npm test Decide on versioning independent or unified. Then automate publishing. For independent versioning using Changesets:

// package.json at root of modrepo

In the rapidly evolving landscape of software development, the way we store, version, and distribute code has undergone a radical transformation. Gone are the days of monolithic codebases where a single change required rebuilding an entire application. Today, the industry standard is modularity—breaking down complex systems into smaller, reusable, and independent components. At the heart of this paradigm shift lies a critical concept that is gaining traction among DevOps engineers, platform architects, and tech leads: Modrepo .

| Feature | Monorepo | | Multirepo | |---------|----------|-------------|-----------| | Scope | Entire company codebase | Single bounded context (e.g., team domain) | Per component/service | | Code sharing | Trivial (everything visible) | Controlled via internal packages | Requires package registry | | Build time | Often slow, requires caching | Fast, parallel by design | Usually fast but fragmented | | Access control | Coarse (folder-level) | Fine-grained (repo-level) | Perfect isolation | | Tooling complexity | High (Bazel, Nix, Turborepo) | Medium (standard tools suffice) | Low (but coordination is hard) | | Cross-repo changes | Atomic | Atomic within the modrepo | Requires multiple PRs |

"name": "@mycompany/billing-modrepo", "workspaces": ["packages/*", "services/*"]

But what exactly is a modrepo? Is it a tool, a methodology, or a philosophy? In this comprehensive guide, we will dissect the term "modrepo" (short for ular Repo sitory), explore its technical underpinnings, outline its benefits over traditional monorepos and multirepos, and provide a step-by-step roadmap for implementing it in your organization. What is a Modrepo? Defining the Middle Ground A modrepo is a repository management strategy that strikes a deliberate balance between a monorepo (one repository containing all code) and a multirepo (many repositories, each containing a single project or module). In a modrepo architecture, related modules that form a logical boundary—such as a microservice and its client libraries, or a plugin ecosystem—are stored together in a single repository, while unrelated systems remain in separate repositories.

Start small. Pick one domain team. Convert their three related services and libraries into a modrepo. Measure the impact on deployment frequency, lead time for changes, and developer satisfaction. You will likely find that the Goldilocks approach—the modrepo—is exactly what your architecture has been missing. Have you already implemented a modrepo in your organization? Share your experiences and tooling choices in the discussion below.

: Define strict size limits. When a module becomes too independent or stable, spin it off into its own modrepo. Pitfall 2: Circular Dependencies Across Modrepos If modrepo A depends on a package from modrepo B , and modrepo B also depends on a package from modrepo A , you’ve created a cycle that forces simultaneous releases—defeating the purpose of modularity.