Building a modular monolith with Fastify - Matteo Collina, Node Congress 2023

Learn how to build a modular monolith with Fastify, separating concerns and avoiding spaghetti code, while leveraging domains, plugins, and encapsulation to achieve scalable complexity.

Key takeaways

Building a modular monolith with Fastify involves setting up folders for routes, plugins, and inventories to separate concerns and avoid spaghetti code.
Model-View-Controller (MVC) architecture is not suitable for scaling complexity, leading to carbonara code.
Domains are the organizational structure of a monolith, where each domain has its own set of plugins, routes, and inventories.
Encapsulation is the process of hiding implementation details and exposing only necessary interfaces.
Breaking encapsulation is necessary to communicate between domains.
Fastify offers a concept called autoload, which automatically sets up routes and plugins.
Plugins can be used to share code between domains.
Decorators can be used to share data between plugins.
The inventory is an object that stores data for a specific domain.
The Fastify plugin can be used to automatically generate routes.
Modular monoliths can be easily migrated to microservices.
MVC architecture is not good enough to handle complexity, leading to spaghetti code.
Building a modular monolith requires thinking about domains, features, and code organization.
Not all systems are suitable for microservices.
Not all domains are suitable for isolation.
Modular monoliths are often confused with monolithic architecture.
It’s not about telemetry or production readiness, but about structuring the code.
Good architecture starts with a clear understanding of the problem domain.
Fastify is suitable for building web applications.
Not all plugins can be loaded through the Fastify plugin.
The best way to handle complexity is to break it down into smaller domains.

Building a modular monolith with Fastify - Matteo Collina, Node Congress 2023

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