Monorepos vs. Microservices: Exploring the Trade-offs in Backend Architecture
In the world of backend system architecture, choosing the right approach is as much about context as it is about technology. Among the many decisions teams face, the debate between microservices and monorepos has persisted in tech circles, often cycling back into relevance as new tools and techniques emerge.
At Hypercolor Digital, we’ve navigated this decision firsthand. While both approaches have their strengths, our experiences with monorepos have revealed some unexpected advantages, particularly in reducing lines of code, increasing development velocity, and simplifying refactoring and maintenance. That said, we’ve also seen scenarios where microservices remain the better choice. Let’s dive into these trade-offs and explore how recent tooling advancements are shifting the conversation.
The Microservices Perspective: Independence and Scalability
Microservices have been heralded in recent history for their ability to promote independence and scalability. By breaking an application into discrete, independently deployable services, teams can work in parallel, scale specific components as needed, and reduce the blast radius of changes. In theory, this sounds great; the successful execution however is extremely difficult to achieve without at least some code or logic overlap between services.
For certain projects, this approach can be very wise. Consider systems with high traffic variability, like an e-commerce platform during peak shopping seasons. The ability to scale only the order processing service, without over-provisioning the entire application, can lead to significant cost savings. Similarly, when teams are distributed or have distinct domain responsibilities, the independence of microservices aligns well with organizational structures in organizations with large development teams.
However, with independence comes complexity. Managing multiple repositories, coordinating cross-service changes, and ensuring there is no coupling between services can introduce significant overhead. For smaller teams or projects with tightly coupled domains, this complexity may outweigh the benefits.
The Monorepo Advantage: Shared Context, Simplified Development
In contrast, a monorepo consolidates an entire codebase into a single repository, fostering a shared context and tighter integration across teams. At Hypercolor Digital, we’ve found this approach particularly effective for projects where services are interdependent or frequently share modules. Here’s why:
Reduced Code Duplication
By leveraging shared module injection, we’ve seen a notable reduction in redundant code. In one project, a shared utility package with common interfaces and models were easily reused across services, cutting down boilerplate code and improving maintainability. In a microservices setup, these shared modules would require careful versioning and duplication across repositories, adding to the cognitive load, and increasing the risk for possible issues as the product matures.
Increased Development Velocity
With everything in one place, our team has been able to move faster. Changes that touch multiple services can be made, tested, and deployed more seamlessly. In a microservices architecture, this process often involves coordinating updates across repositories, synchronizing service versions, and navigating dependency management—a workflow that can slow progress.
Easier Refactoring and Maintenance
Refactoring in a monorepo is inherently simpler. When updating a shared component, we can immediately see how the change impacts other parts of the system. This visibility reduces the likelihood of breaking changes and simplifies code reviews. In microservices, such changes often require extensive testing across separate repositories, increasing the effort and risk.
The Role of Modern Tooling
One reason monorepos are gaining renewed attention is the advancement of tools that address historical pain points. In the past, managing a large monorepo was daunting—build times could balloon, and dependency management was a headache. However, tools like NPM Workspaces and Yarn Workspaces have significantly improved the developer experience.
With features like efficient package management, dependency hoisting, and workspace linking, these tools make it easier to maintain modularity within a monorepo without sacrificing the benefits of a unified codebase. Additionally, tools like Nx and Lerna provide robust support for managing builds and testing, even as monorepos scale.
This evolution in tooling has made the monorepo approach far more feasible for teams, prompting a resurgence of interest within the community.
Choosing the Right Approach for Your Team
As with most architectural decisions, the choice between monorepos and microservices depends on context:
When Microservices Shine
If your application requires independent scaling, has clear domain boundaries, or involves large, distributed teams, microservices may still be the better choice. Their ability to isolate changes and scale specific components can provide a clear edge in these scenarios.
When Monorepos Win
For smaller teams, projects with tightly coupled domains, or those looking to optimize for shared context and rapid iteration, a monorepo can simplify workflows and improve productivity. The ability to leverage shared modules and maintain a single source of truth can outweigh the trade-offs of increased repository size.
Reflecting on the Future
As the tools and technologies supporting both approaches continue to evolve, the lines between them may blur. It’s worth revisiting this decision regularly, especially as your team’s needs and the ecosystem change.
At Hypercolor Digital, our experiences with monorepos have reshaped how we approach backend architecture, but we remain open to the possibilities microservices offer. Ultimately, the best choice is the one that aligns with your team’s goals, constraints, and vision for the future.
"Architecture isn’t a battle of absolutes—it’s an opportunity to explore what works best for your unique challenges and ambitions."