NESTJS AGENCY FOR BACKENDS WITH STRUCTURE
NestJS brings structure to large Node codebases. We model domains clearly, encapsulate integration logic and deliver testable services.
What is NestJS?
NestJS is an open-source framework for server-side applications on Node.js, written in TypeScript. It provides a fixed structure of modules, controllers and services and uses dependency injection. Under the hood it runs on Express or, optionally, Fastify. nextlevels uses it to build APIs and microservices, including the backend of its own CMS framework next-cms.
We areNestJSprofessionals
From monoliths to service-oriented – we use NestJS primitives for clean boundaries between HTTP, queues and database access.
- Modules, providers and clean dependency injection
- DTOs, validation pipes and Swagger/OpenAPI
- Auth strategies (JWT, OAuth) and policy guards
- Integration with Prisma/ORM and messaging
NestJS or plain Express?
NestJS sits on top of Express or Fastify. So the question is not either-or, but how much structure your backend needs.
| Criterion | NestJS | Plain Express or Fastify |
|---|---|---|
| Structure | Given: modules, controllers, services, dependency injection | Free, the team defines everything itself |
| Getting started | More concepts at the beginning | Ready in minutes |
| Several developers | All services look alike, onboarding is faster | Every project looks different |
| API docs and validation | OpenAPI and input validation are documented building blocks | Assemble them yourself from individual libraries |
| Microservices | Transports for Redis, MQTT, NATS, RabbitMQ, Kafka and gRPC documented | Connect them yourself |
| Fits when … | the backend grows and is maintained for a long time | it is a small service or a single webhook |
As of October 2026, according to docs.nestjs.com.
Modular architecture in Node.js
NestJS brings proven concepts inspired by Angular to the server: clear modules, providers and clean export edges between domains.
OpenAPI & validation out of the box
DTOs with class-validator, automatic Swagger documentation and consistent error formats accelerate partner integrations.
Microservices & transport layers
TCP, Redis, MQTT or message queues: Nest unifies different transporters under consistent patterns for handlers and guards.
Testability & scalable teams
DI eases mocking and isolating use cases – ideal when multiple squads work on the same backend.
NestJS in our own products
next-cms and NEXT Orbit
next-cms is our own full-stack CMS framework: backend on NestJS, admin interface in React on TanStack Router and Query. NEXT Orbit, our CRM for customers, projects, monitoring and forms, is built on next-cms as well.
Kumho Tire Europe app
The Kumho Tire Europe app loads its content from the next-cms backend.
B2B APIs & partner ecosystems
Stable contracts, rate limits and documented endpoints: NestJS helps scale external integrations without sprawl.
Internal platform teams
Consistent building blocks for health checks, metrics and logging: platform squads can enforce standards without slowing down each team.
What we build for you with NestJS
Bookable individually or as a project.
APIs for web and app
REST or GraphQL, with OpenAPI documentation, input validation, authentication and permissions.
Modular monolith or microservices
We usually start with cleanly separated modules in one application and split off services only when load or team size demand it.
Background jobs and events
Queues, scheduled tasks and messages between services, with retries on failure.
Migration from Express
Existing Node.js services move to NestJS module by module. The application stays in operation.
Upgrade to the current version
NestJS 12 was released in August 2026 and ships its core packages as ES modules. We check dependencies and bring your project up to date.
Code review and architecture
We check module boundaries, tests and data access and deliver a prioritised list.
How a NestJS project runs
Cost and duration depend on scope. Our project calculator gives you a first range; the binding figure comes with the offer after the workshop.
First call
You describe the goal, the users and the systems you already have. We tell you straight away whether NestJS fits or whether another route is better.
Architecture workshop
We define the data model, interfaces and hosting and cut the scope into packages. The offer is based on that.
Delivery in iterations
We ship in short steps to a test environment, so you see every stage. Tests and code review are part of each step.
Go-live and operations
We deploy to your infrastructure or run the application for you. After that we handle updates and monitoring if you want.
Frequently asked questions about NestJS
Your question isn't here? Ask us directly
When is NestJS worth it?
As soon as a Node.js backend grows, several developers work on it and it should run for years. The fixed structure pays off then. For a single webhook or a short script, NestJS is too much.
Microservices or monolith?
Usually a modular monolith first: one application with clearly separated modules. That is easier to operate. NestJS lets you split individual modules off as separate services later, when load or organisation demand it.
Express or Fastify underneath?
Express is the default and has the most extensions. Fastify is the alternative that NestJS officially supports. We decide based on load profile and the libraries you need.
Can we migrate an existing Node service to NestJS?
Yes, step by step. New features are built as NestJS modules, existing logic moves over bit by bit. The system keeps running the whole time.
How do you secure a NestJS API?
With authentication via JWT or OAuth, permissions per role, input validation on every endpoint and rate limiting. Tests and code review are part of every step.
What does a NestJS project cost?
NestJS is MIT-licensed and free. Effort depends on interfaces, data model, permissions and load requirements. Our project calculator gives you a first range.
Your edge with NestJS
Teams grow faster when architecture is predictable. NestJS provides exactly that frame – we fill it with your domain.
Consistent patterns across all services
Better onboarding times for new developers
Stable releases with automated tests
Clear interfaces to frontends and partners
Read on and check
APIs and microservices
Our service in detail.
Microservices architecture
When the split pays off.
Project calculator
A first cost range for your backend.
Ready for your NestJS project?
Let's talk about your requirements – we'll get back to you within 24 hours with concrete next steps.
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