Terraform Advanced — Monorepo vs Polyrepo Modules

Should all modules live in one repo or each get their own?

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Polyrepo (One Module per Repo)

github.com/org/terraform-aws-vpc      ← v2.1.0
github.com/org/terraform-aws-eks      ← v1.3.0
github.com/org/terraform-aws-rds      ← v3.0.0

Pros	Cons
Independent versioning per module	Many repos to manage
Terraform Registry compatible	Cross-module changes need multiple PRs
Clear ownership per repo	Harder to discover modules

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Monorepo (All Modules in One Repo)

github.com/org/terraform-modules/
├── modules/
│   ├── vpc/
│   ├── eks/
│   └── rds/
└── README.md

# Reference a subdirectory
module "vpc" {
  source = "git::https://github.com/org/terraform-modules.git//modules/vpc?ref=v2.1.0"
}

Pros	Cons
One repo to manage	All modules share one version tag
Cross-module changes in one PR	Can’t version modules independently
Easy to discover	Not Registry compatible

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Recommendation

Team Size	Recommendation
1–5 engineers	Monorepo — simplicity wins
5–20 engineers	Monorepo with module-level tags
20+ engineers	Polyrepo — independent teams need independent releases

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What’s Next?

Learn the module wrapper pattern.

← Publishing to Registry Module Wrapper Pattern →