NestJS Development

Backends with a clear structure – for APIs that stay maintainable for years.

dectria builds backends with NestJS: REST and GraphQL APIs with a clear module structure, roles and permissions, background jobs and documented interfaces. We use NestJS in production in our own products.

NestJS gives projects a fixed structure of modules, controllers and services. We solve cross-cutting concerns such as authentication, validation and error handling once, centrally, instead of in every endpoint.

Together with a frontend in React or Next.js, this creates a consistent TypeScript stack in which types are shared between frontend and backend.

Official website

Your contact Michael Jauk Contact for backend & architecture

What is NestJS – and when is it worth it?

NestJS is a TypeScript framework for Node.js backends. It builds on Express or Fastify and adds a fixed architecture with modules, dependency injection and building blocks for authentication, validation and error handling.

NestJS is worth it for backends with a lot of business logic, several developers and a long lifetime. It is not worth it for small APIs with a handful of endpoints: Fastify or an API endpoint in Next.js is leaner there.

Express, Fastify or NestJS?

	Express	Fastify	NestJS
Structure	no conventions	few conventions, plugins	fixed architecture with modules and dependency injection
Learning curve	low	low	higher, then consistent across the team
Validation & documentation	build it yourself	built in via schemas	built in via pipes and OpenAPI modules
Suited for	small services, prototypes	lean, fast APIs	larger backends with a lot of business logic

What We Build with NestJS

REST API Development GraphQL APIs Modular Architecture & Dependency Injection Authentication & Authorization (OAuth / JWT) Roles & Permissions via Guards Databases with TypeORM / Prisma / Drizzle Background Jobs & Queues OpenAPI Documentation Unit & E2E Testing Integration with Keycloak & Entra ID

Use Cases

Typical Use Cases

APIs for Business Applications

REST and GraphQL APIs with a clear module structure, role-based access control and documented interfaces.

Background Data Processing

Imports, calculations and reports as queued jobs that run reliably without blocking the API.

Backends for SaaS Products

Multi-tenant backends where permissions, validation and logging are handled centrally and consistently.

References

Selected Projects

Web Application

Klanglicht - Art Festival of Bühnen Graz

Klanglicht Audio Guide

Mobile App

Radio Soundportal

Soundportal App

Web Application

Österreichische Raiffeisen-Sicherungseinrichtung eGen (ÖRS)

Deposit Insurance Payout Platform

View all references

FAQ

NestJS FAQ

Why NestJS instead of Express?

NestJS builds on Express or Fastify and brings a fixed architecture with modules, dependency injection, guards and pipes. For larger backends, this saves effort in the long run because every team member finds the same structure. For small services, Express or Fastify alone is often the better choice.

Which databases does dectria use with NestJS?

PostgreSQL, MariaDB and Microsoft SQL Server. As ORM, we use TypeORM, Prisma, Drizzle or Sequelize depending on the project. We choose the database based on requirements and existing infrastructure.

Does dectria support GraphQL with NestJS?

Yes. NestJS includes a GraphQL module, and we have built GraphQL APIs with it. GraphQL is worth it when different interfaces need very different data. For simple interfaces and external partners, REST with OpenAPI usually remains the clearer choice.

How does dectria document NestJS APIs?

Mostly spec-first: the OpenAPI specification is written before the code and serves as the shared contract. From it, we generate type-safe clients and backend interfaces. This keeps code and documentation in sync.

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