Senior Backend Engineer (NestJS)

About the role

Techkraft is looking for a Senior Backend Engineer (NestJS) in Kathmandu to design, develop and maintain scalable backend services and APIs. The role covers secure APIs, integrations, background processing, real-time features, testing and backend architecture, within a hands-on senior position where fintech/payments experience is highly preferred.

Key responsibilities

• Build and extend REST APIs and WebSocket features in a modular NestJS application (modules, controllers, services, DTOs, guards, interceptors, pipes).
• Model and evolve data in PostgreSQL (TypeORM) and MongoDB (Mongoose), including migrations, data backfills, indexing and query tuning.
• Implement policy-based authorization and data scoping.
• Build asynchronous and scheduled processing: queues with retries and dead-letter handling, idempotent jobs, cron jobs and event-driven flows.
• Integrate third-party services such as OAuth2 APIs, signed webhooks and file-based exchanges.
• Generate documents and data files (PDFs, Excel and CSV imports and exports, large-file processing).
• Protect sensitive data with field-level encryption, log redaction, audit trails and strict input validation.
• Write unit and integration tests against real databases and keep OpenAPI documentation current.

Required profile

• 4+ years building production APIs with NestJS and Node.js in TypeScript.
• Strong PostgreSQL experience, including schema design, transactions, indexing and query plans.
• Experience with MongoDB, Redis and a job queue (BullMQ or similar).
• Authentication and authorization (JWT, OAuth2, SSO, CASL or similar).
• Nice to have: payments or fintech experience, multi-tenant SaaS design, Socket.IO, Puppeteer, AWS, Terraform and GitHub Actions.

Required skills

• TypeScript, NestJS, PostgreSQL, MongoDB, Redis, BullMQ
• TypeORM, Mongoose, JWT, OAuth2, OpenAPI, Jest, Supertest, Docker and Docker Compose
• Class-validator, class-transformer, Swagger, and class-based testing tools

Candidates should submit a CV detailing each relevant project (dates, role, team size, responsibilities and technologies) and state their years of hands-on experience with NestJS, TypeScript and other required technologies.