Order even in a large codebase
A modular structure and TypeScript keep the code readable as the system and the team grow. New developers get up to speed faster.
NestJS: reliable APIs and integrations
We build reliable backend systems, APIs and integrations with NestJS that connect your online store, ERP and CRM into one connected whole. Opus Online is a Tallinn-based software development company with more than 15 years of experience with business-critical systems.
We don’t start from the technology but from your goal. First we find out whether NestJS is the right choice for your project.
Why choose NestJS?
NestJS is a backend framework built on Node.js and TypeScript for building APIs, integrations and business-critical server applications. For a business, that means three things.
Reliable integrations
Integrations with ERP, CRM, payment and warehouse systems, queues and scheduled jobs all follow one consistent logic in NestJS and are easy to test.
One language for frontend and backend
The same TypeScript in the React or Next.js frontend and the NestJS backend means fewer bugs and faster development.
- 25+specialists in our team
- 3+years of NestJS projects
- 6public NestJS references
- ISO 27001certified information security
What we build with NestJS
APIs and integrations
REST and GraphQL APIs and integrations with ERP, CRM, PIM and payment solutions.
Backends for SaaS products
Users, roles, plans, payments and multi-tenant architecture.
Self-service and B2B portals
Customer-specific prices, orders, contracts and documents securely in one place.
Backends for headless online stores
Order, stock and pricing logic alongside MedusaJS or Magento.
AI solutions and data processing
Connecting language models, document processing and automation to your business processes.
Taking over an existing project
Audit, version upgrades and maintenance for a solution built by another team.
NestJS projects
We have extensive experience in developing IT software and e-commerce solutions for businesses, spanning from the financial sector to insurance and pharmaceutical industries. We serve as a long-term partner for both large corporations and rapidly growing startups.
Is NestJS the right choice for your project?
NestJS isn’t right for every project, and we say so honestly at the first meeting. For a small service, plain Express.js may be enough, and for a classic web application PHP and Laravel are a good choice too.
| Feature | NestJS | Express.js | PHP (Laravel) |
|---|---|---|---|
| Best suited for | large APIs, integrations, SaaS | small services and prototypes | classic web applications and portals |
| Structure and code maintainability | very good | depends on the team | good |
| Same language as the React frontend | yes (TypeScript) | yes | no |
| Microservices and queues | built-in support | by hand | with packages |
| Testability | very good | depends on the team | good |
| Initial budget | medium | lower | medium |
| Further development over the years | easy | more complex | easy |
Taking over and upgrading an existing NestJS project
We take over NestJS and Node.js projects built by another agency or an in-house team. We start with a code and security audit, which shows you what is in order, what needs fixing and what is critical.
After the takeover we keep looking after the solution: monitoring, security updates and hosting are part of our maintenance service.
How we work
You talk directly to the people building your solution, not to intermediaries.
Kick-off meeting
We listen to your goals and tell you honestly whether NestJS fits.
Analysis and estimate
Functionality, integrations, risks, timeline and budget.
Development in cycles
A working version every couple of weeks.
Testing and go-live
Speed, accessibility (WCAG, EAA) and security (OWASP).
Maintenance
We stay with the solution after launch too.
Technologies:
- NestJS
- TypeScript
- Node.js
- PostgreSQL
- GraphQL
- Redis
- Docker
- AWS
Frequently asked questions
How much does a NestJS backend or API cost?
A NestJS project usually costs between €10,000 and €70,000. A smaller project can cost less and a large platform more, as the price depends on the specifics of the project. We give an exact estimate after a short analysis.
How long does a NestJS project take?
Usually 1–6 months; a larger project can take longer.
Which to choose, NestJS or Express.js?
Express.js suits small services. NestJS is the choice when the system grows, the team is larger and long-term maintainability matters.
Is NestJS suitable for high-load systems?
Yes. NestJS supports horizontal scaling, queues and microservices, so the system grows with the load.
Which frontend do you connect a NestJS backend to?
Mostly React or Next.js, but a NestJS API also serves mobile apps and other companies’ systems.
Can you take over a project built by another agency?
Yes. We start with a code and security audit and propose a plan for what comes next.
Where is a NestJS solution hosted?
On AWS or Zone, depending on the load and your requirements.
Get in touch
Planning a new API, integration or SaaS product, or want to hand over an existing NestJS solution? Write to us, and let's discuss which solution suits you.
