When Express Isn't Fast Enough: The Need for Speed
For years, Express.js has been the de facto standard for building web applications in Node.js. But for high throughput, low latency APIs, every millisecond counts. Fastify was born out of a need for speed, designed from the ground up to be one of the fastest web frameworks in the ecosystem. It achieves this through a focus on low overhead, intelligent JSON parsing, and a powerful plugin architecture.
However, an engineer who simply treats Fastify as a "faster Express" will fail to leverage its most powerful features. An expert understands its asynchronous bootstrapping, how to use its hooks to modify the request lifecycle, and how to use its built in schema-based validation to both secure and accelerate their API by optimizing JSON serialization. This playbook explains how Axiom Cortex vets for the deep understanding required to build truly high performance services with Fastify.
How Axiom Cortex Evaluates Fastify Developers
Our vetting process is designed to find engineers who think about performance at every level of the stack, from routing to serialization. We test for the skills that are essential for building blazing-fast Node.js APIs.
Dimension 1: The Fastify Lifecycle and Plugin Architecture
This dimension tests a candidate's understanding of Fastify's core architecture.
- Asynchronous Bootstrapping: Can they explain how Fastify's `ready()` and `listen()` methods work and why its asynchronous startup process is important?
- Plugin and Hook System: Can they design a solution that uses decorators and hooks to add functionality to the framework in a clean, encapsulated way?
Dimension 2: Performance and Schema-Driven Optimization
This dimension tests a candidate's ability to use Fastify's schema features to maximize performance.
- Schema-based Validation and Serialization: A high scoring candidate will immediately talk about using JSON Schema to define their routes. Can they explain how this not only validates requests but also allows Fastify to use a highly optimized JSON serializer (`fast-json-stringify`)?
- Logging: Are they familiar with Fastify's built in, low-overhead logger (Pino) and how to use it effectively in production?
From a Standard API to a High-Throughput Service
When you staff your team with engineers who have passed the Fastify Axiom Cortex assessment, you are investing in a team that can build backend services that can handle extreme levels of traffic with minimal latency. They will be able to squeeze every ounce of performance out of the Node.js runtime, building APIs that are not just functional, but blazingly fast. This focus on performance is also key for developers working with similar modern frameworks like FastAPI in the Python world or Fiber in the Go world.