How do you structure a monorepo vs multiple repos? Pros, cons, and your experiences.

[Suhebdevtechnosys]

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Do you prefer keeping all your code in one big repo, or do you split it into multiple smaller repos? What are the advantages and disadvantages of each method based on your experience?

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[fernandosalomao]

Hi @Suhebdevtechnosys

Choice often depends on team topology, the kind of systems you’re building (microservices vs. a tightly‑coupled product), governance needs, and how your CI/CD is set up.

Monorepo (one big repo): Best when components evolve together, you need atomic refactors across the whole stack, and you want one place to version, test, and release.

Multi‑repo (many smaller repos): Best when services are independently owned/released, with clear boundaries, different cadences, and stricter access controls.

Monorepo: Advantages & Disadvantages

Advantages

• Atomic changes across boundaries. One PR can refactor interfaces across backend services, shared libs, IaC modules, and pipelines in a single commit—handy when you’re modernizing foundations or renaming resources across environments.
• Unified tooling & standards. One place to enforce pre‑commit hooks (fmt/validate/tflint/Checkov), secret scanning, dependency policies, and trunk‑based or Gitflow branching. Easier to make standards non‑optional.
• Onboarding speed. New developers get “everything” with one clone.
• Single source of truth for shared modules. Shared Terraform modules or platform templates can live alongside consumers, reducing drift when APIs change.

Disadvantages

• Scale & CI complexity. Build and test times grow; you need smart scoping (path‑based pipelines, Bazel/Nx/workspaces) to avoid rebuilding the world.
• Access control is coarser. Repo‑level permissions mean more people can “see” everything. Fine‑grained isolation of sensitive systems or vendor‑specific IP is harder.
• Release cadence coupling. Teams may wait on others; coordinating tags/versions across unrelated features can slow delivery.
• History & noise. Git history and notifications become heavy; small changes are buried among unrelated churn.

Multi‑repo: Advantages & Disadvantages

Advantages

• Clear ownership boundaries. Each service/module has its own repo, reviewers, release cadence, and access control—simplifies compliance and vendor engagement.
• Faster CI & focused quality gates. Pipelines are scoped; tests run only for what changed; security scanning can be tuned per component.
• Independent versioning. You can cut releases and hotfixes without coordinating across the entire product; easier to maintain LTS branches per service.
• Risk isolation. A bad change in one component doesn’t block builds/releases for others.

Disadvantages

• Cross‑repo change friction. Multi‑service refactors require choreography (multiple PRs, dependency bumps).
• Discoverability & duplication. Shared utilities can fork subtly; enforcing platform standards and policy‑as‑code uniformly is harder.
• Template drift. Terraform module consumers may lag behind; without automated update flows, versions diverge quickly.
• Onboarding overhead. New engineers must find the “right” repos and wire up local dev across many codebases.

My recommendation:

I am definitely using both methodologies.

Use multi‑repo for microservices, Terraform modules, and platform components, each with its own lifecycle and ownership.

Use monorepo (or a small set of product repos) for tightly coupled application codebases (e.g., a single web app with multiple packages), or for cross‑cutting config, policy-as-code and templates that must stay in lock‑step.

Glad I could help! If this clarifies your question, feel free to mark it as an answer.

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[pratikrath126]

Great breakdown by @fernandosalomao! I'd add that the tooling ecosystem has shifted this decision significantly in recent years.

Previously, monorepos were scary because of build times and git bloat. Now, tools like Turborepo, Nx, and Moon have solved the "build everything" problem with intelligent caching and affected-graph execution. If you're using TypeScript/JS, a monorepo with workspace tools is often strictly better than multi-repo because you get atomic commits without the CI penalty.

For Multi-repo, the hidden cost is often 'dependency hell'—updating a shared library requires a PR in the lib, publishing, then N PRs in consuming apps.

Rule of Thumb:

• Monorepo: If your projects share >20% of code/types/config or deploy together.
• Multi-repo: If teams strictly do not talk to each other, or if the projects are completely distinct ecosystems (e.g., a Rust embedded backend vs a Swift iOS app where code sharing is impossible).

[Shreyas-S-809]

I’ve worked with both setups and honestly — neither is “better”, they just optimize for different kinds of pain.

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Monorepo (everything in one repository)

What it feels like
You open one repo and the entire system is there: frontend, backend, shared utils, infra configs, maybe even ML models. It feels clean conceptually because the product lives in one place.

Why teams love it

• Atomic changes — if I change an API response, I update backend + frontend in the same PR. No version mismatch headaches.
• Shared code is trivial — no publishing packages, no waiting for releases. Import and go.
• Refactors are safe — rename a function across the company in one commit.
• Onboarding is easier — clone once → run once → everything works.

Why it hurts

• CI gets slow unless you invest in caching, task runners (Nx/Turbo/Bazel), etc.
• Permissions are messy — everyone technically has access to everything.
• Tooling becomes mandatory — without good build orchestration the repo becomes unusable.
• Git history gets heavy over time.

Monorepo works best when
You’re building one product with many parts that evolve together (SaaS, apps, platforms).

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Multiple Repositories (repo per service/package)

What it feels like
Each repo is a small independent world. Clean boundaries, clear ownership.

Why teams love it

• True isolation — services can evolve independently
• Fast CI per repo
• Clear ownership — “this team owns this repo”
• Security & access control easier

Why it hurts

• Cross-repo changes are painful
  You update API → publish package → bump versions → update consumers → pray.
• Version hell — someone always depends on an old contract
• Local development harder — running full system requires orchestration
• Refactors are expensive — sometimes avoided entirely

Multi-repo works best when
You have separate products or independently deployable services owned by different teams.

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The real difference (in practice)

Monorepo optimizes for development speed
Multi-repo optimizes for organizational boundaries

You’re basically choosing where you want complexity to live:

• Monorepo → tooling complexity
• Multi-repo → human/process complexity

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My personal rule of thumb

I default to monorepo until the org structure forces multi-repo.

Because most early teams don’t actually have independent services — they have tightly coupled components pretending to be microservices. A monorepo makes that reality easier instead of fighting it.

Later, when teams truly operate independently and release cycles diverge, splitting repos starts to make sense.

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Short version:
If your system changes together → monorepo
If your teams operate independently → multi-repo