Reduced per-request overhead
Fast routing, schema-based optimized serialization and lightweight hooks keep the cost of the framework itself low — lower than Express in the benchmarks published by the project.
Expertise · Fastify
Fastify Development: Fast Node.js APIs with Explicit Contracts
Etixio handles Fastify development for your Node.js APIs, with explicit data contracts and a modular structure. We build new services, take over existing ones and build the APIs that expose your AI features, from response streaming to production monitoring.
Understanding the technology
Fastify in your project.
Fastify is a framework for building web services with Node.js. It provides, among other things, a plugin-based structure and schema-based mechanisms to describe data exchanges. We use it as a foundation for APIs, complementing these tools with the project’s business rules and quality practices.
The benefits for your product
Why choose Fastify?
Fastify aims for low per-request overhead and a modern developer API. It is well suited to high-traffic APIs, microservices and integration services.
JSON Schema validation
Schemas describe requests and responses, and are used for automatic validation and OpenAPI documentation.
A plugin architecture
Each plugin encapsulates its dependencies and routes, which keeps responsibilities separate as the API grows.
Built-in TypeScript and logging
Types provided for the framework and the Pino logger for structured logs, correlated from one request to the next.
What we cover
The work we take on.
Contracts
Define the input and output schemas of endpoints.
Modules
Organize plugins, dependencies and application responsibilities.
Measurement
Test data exchanges and measure behavior under a representative load.
Our Fastify expertise
The Fastify ecosystem we master.
Framework core
Routing, lifecycle hooks, plugin system with encapsulation, validation with Ajv and dedicated serializers.
Essential plugins
@fastify/swagger for OpenAPI documentation, @fastify/auth and JWT, CORS, Helmet, rate limiting, compression and multipart.
Data
PostgreSQL, MongoDB and Redis plugins, or Prisma, TypeORM and Knex, with connection pooling.
Testing & load
HTTP tests via injection without a network server, Jest or the Node.js test runner, load testing with k6 or Artillery.
Fastify runs on Node.js and can serve as the HTTP layer for NestJS when the project needs more structure.
Fastify and AI
A Fastify API for your AI features.
For an AI feature built into a product, the API checks permissions, validates inputs with schemas, calls the model and streams the response to the interface. Pino’s structured logs make it easier to track exchanges and costs. We build these services and take over prototypes to bring them to production. See our AI agents and chatbots.
In the field
From technology to real-world use.
For a partner integration service, we define the accepted formats and error responses before developing the operations. Schemas and checks reduce ambiguity between systems. Tests also cover access control, repeated calls and situations where a dependency stops responding.
The choices that matter
The choices to examine before building.
The choice of framework does not guarantee the throughput of a complete application. Data access and external calls can be the main sources of latency. We measure user flows under a representative load and keep transport, business rules and storage as distinct responsibilities.
From work to deliverables
Delivered work your team can take over.
The scope of the engagement specifies the components to build or take over and the acceptance criteria. We prepare what is needed to understand the changes, verify them and continue the work.
- Services and API contracts
- Business rule tests
- Deployment procedures
Frequently asked questions
Fastify development: your questions.
What is Fastify and why is it fast?
Fastify is a web framework for Node.js. Its speed comes from efficient routing, serialization compiled from JSON schemas and a lightweight hook and plugin system. In a real application, data access often remains the main source of latency.
Is Fastify suitable for enterprise applications?
Yes, for high-traffic APIs, microservices and integration services. Its schemas, encapsulated plugins and structured logging help maintain a critical API.
What is the difference between Fastify, Express and NestJS?
Fastify is more focused on performance and schema validation than Express, while remaining lightweight. NestJS provides a complete architecture and can use Fastify as its HTTP server. The choice depends on the need for structure and the load profile.
How should a Fastify application be structured?
With plugins, routes grouped by domain, hooks for cross-cutting concerns (authentication, logging) and a clear separation between infrastructure plugins and business plugins.
How do you optimize the performance of a Fastify API?
Declare response schemas for serialization, keep handlers asynchronous, use connection pools and caching, then measure regularly with load tests to target the real points of contention.
Which Fastify plugins are essential?
OpenAPI documentation, authentication, CORS, Helmet for security headers, rate limiting, compression and file upload handling, complemented by project-specific business plugins.
How do you test a Fastify application?
The inject() method makes it possible to test routes without starting a network server. This is complemented by unit tests of services, schema checks and load tests with k6 or Artillery.
Is Fastify a good fit for exposing an AI assistant?
Yes. Fastify handles model response streaming and input validation well. For production, we add permission checks, rate limits, logs, cost tracking and evaluations.
What collaboration models do you offer?
A fixed-price project for a defined scope, a dedicated team to evolve your APIs over time, or a targeted engagement (performance, plugins, migration to Fastify).
Let’s talk about your technical context.
Tell us about the application, the issue to address and the known constraints. We will review the dependencies and the initial scope of work with your team.