Senior Node.js Developer - (NestJS) - Remote - 3 Months - Octopus by RTG

This role is suitable for a Senior Backend Developer with 5+ years of experience specializing in Node.js, NestJS, TypeScript, and JavaScript.

The candidate should be skilled in building scalable backend systems, designing and integrating RESTful APIs, working with databases, applying software design principles, writing clean code, and using Git.

They should be familiar with independently developing and troubleshooting high-performance applications, solving complex technical problems, and collaborating effectively with cross-functional teams.

1. How does NestJS structure a backend application, and how would you organize a large-scale project?

NestJS uses modules, controllers, providers, and decorators to organize application logic. I would separate features into domain-focused modules, keep controllers thin, and place business logic in services with clear interfaces and dependency injection.

2. How would you implement request validation in a NestJS REST API?

I would use DTOs with class-validator and enable NestJS's global ValidationPipe, typically with transformation and whitelisting enabled. This ensures invalid or unexpected input is rejected before reaching the business logic.

3. What is the difference between middleware, guards, interceptors, and pipes in NestJS?

Middleware runs before route handling, guards determine whether a request is authorized, pipes transform or validate data, and interceptors wrap request execution for concerns such as logging, response mapping, or performance measurement.

4. How would you design authentication and authorization for a NestJS API?

I would use Passport strategies with JWT or another appropriate identity provider, protect routes with authentication guards, and implement role- or permission-based authorization with custom guards or decorators. Tokens should be validated securely, and sensitive credentials must never be logged.

5. How do you handle errors consistently across a Node.js and NestJS application?

I would use NestJS exceptions and custom exception filters to map errors to consistent HTTP responses. Unexpected errors should be logged with correlation information while exposing only safe, meaningful details to API clients.

6. What practices would you follow when designing scalable RESTful APIs?

I would use resource-oriented URLs, appropriate HTTP methods and status codes, consistent error formats, pagination, filtering, and versioning where necessary. The API should also be idempotent where appropriate and documented with OpenAPI or Swagger.

7. How would you improve the performance of a Node.js backend?

I would profile the application first, then optimize database queries, add suitable indexes and caching, avoid blocking synchronous operations, and use pagination for large datasets. For CPU-intensive work, I would consider worker threads or moving the workload to asynchronous background jobs.

8. How do you manage database transactions and consistency in a Node.js service?

I would use the transaction facilities provided by the database or ORM and keep all related operations within a clearly defined transaction boundary. Transactions should be short, handle rollback correctly, and be combined with appropriate isolation levels and constraints.

9. What testing strategy would you use for a NestJS application?

I would write unit tests for services and domain logic, integration tests for repositories and external integrations, and end-to-end tests for critical API flows. Dependencies should be mocked selectively, while tests should also verify validation, authorization, error handling, and edge cases.

10. How would you build and deploy a reliable Node.js service using modern Git practices?

I would use small feature branches, clear pull requests, automated linting, type checking, tests, and security checks in CI. Deployment should use environment-based configuration, health checks, structured logging, graceful shutdown, and a rollback strategy.

Robusta Technology Group’s Octopus is hiring a Senior Node.js Developer for a fully remote, three-month engagement with a UAE-based client. You’ll build scalable, reliable backend applications, develop and integrate RESTful APIs, and apply clean-code and modern engineering practices using Node.js, NestJS, TypeScript, JavaScript, databases, and Git. Salary: not disclosed. Apply to work with a leading technology consultancy behind 300+ international projects and help deliver high-impact digital solutions across Europe, the Middle East, and North America.