---
title: "Packwerk"
description: "2 posts about Packwerk, summarised, each linking to the original."
---

# Packwerk
> 2 posts about Packwerk, summarised, each linking to the original.

## Articles

### [Enforcing Modularity in Rails Apps with Packwerk](https://yomu.fyi/post/enforcing-modularity-in-rails-apps-with-packwerk.md)
- Company: [Shopify](https://yomu.fyi/company/shopify.md)
- Author: 2023-10-18
- Published: Sep 23, 2020

Large Rails monoliths can develop high coupling, low cohesion, cross-component calls, shared Active Record models, and classes that know too much because Ruby and Rails provide limited boundary enforcement. Shopify created Packwerk, an open-source static analysis tool that groups Ruby files into packages and enforces dependency and privacy boundaries, including controlled public APIs for constants. It reports the violation type and location with actionable next steps, integrates with CI, and can run locally; installation begins by adding the gem and running packwerk init. Because Ruby static analysis is complex, Packwerk ignores constants that are not autoloaded, reducing false positives at the cost of false negatives. The excerpt says it runs in six Shopify Rails applications, with 48 packages and 30 boundary enforcements in the core codebase, while adoption also prompted work on dependency inversion.


### [Under Deconstruction: The State of Shopify’s Monolith](https://yomu.fyi/post/under-deconstruction-the-state-of-shopify-s-monolith.md)
- Company: [Shopify](https://yomu.fyi/company/shopify.md)
- Author: 2023-10-18
- Published: Sep 16, 2020

Shopify describes the ongoing effort to modularize its core Ruby on Rails monolith, which contains more than 2.8 million lines of Ruby and 500,000 commits. The initiative organizes code into independently owned components intended to narrow developer focus, reduce affected test suites, preserve contracts, and clarify operational ownership, while recognizing that large-scale refactoring is also a people problem. The work has already improved exception triage, distributed codebase chores, and design awareness, while its current practices emphasize grassroots participation, tooling, targeted reviews, and a holistic architectural view. Packwerk restricts dependencies for about a third of the 37 main-monolith components. Shopify is pursuing a cleaner dependency graph, componentized Rails applications by default, and isolated component tests, while reserving service extraction for cases such as storefront rendering and credit-card vaulting.