Senior Backend Engineer (NestJS)

About the Role

We are looking for a Senior

Backend Engineer - NestJS to design, develop, and maintain scalable

backend services and APIs using NestJS, Node.js, TypeScript,

PostgreSQL, MongoDB, and Redis. You will work on secure APIs,

integrations, background processing, real-time features, testing, and backend

architecture while contributing to a high-quality, production-ready platform.

This is a hands-on senior role requiring strong backend engineering, problem-solving, and experience building

production-grade applications. Fintech/payments experience is highly

preferred.

Responsibilities

• Build

  and extend REST APIs and real-time (WebSocket) features in a modular NestJS

  application: modules, controllers, services, DTOs, guards, interceptors, and

  pipes.

• Model

  and evolve data in PostgreSQL (TypeORM) and MongoDB (Mongoose), including

  deploy-safe migrations, data backfills, indexing, and query tuning.

• Implement

  policy-based authorization and data scoping for new features.

• Build

  asynchronous and scheduled processing: queues with retries and dead-letter

  handling, idempotent jobs, cron jobs, and event-driven flows.

• Integrate

  third-party services: OAuth2 APIs, signed webhooks, schema-driven XML and JSON

  payloads, and file-based exchanges.

• Generate

  documents and data files: PDFs, Excel and CSV imports and exports, and

  large-file processing.

• Protect

  sensitive data with field-level encryption, log redaction, audit trails, and

  strict input validation.

• Write

  unit tests and integration tests against real databases, and keep the OpenAPI

  documentation current.

Required

• 4+

  years building production APIs with NestJS: dependency injection, custom

  providers, dynamic modules, guards, interceptors, pipes, exception filters, and

  the request lifecycle.

• 4+

  years of Node.js backend development in TypeScript.

• Strong

  PostgreSQL: schema design, transactions, indexing, query plans, and locking.

  Production experience with TypeORM or a comparable ORM, including migrations.

• MongoDB

  with Mongoose, including aggregation pipelines and data migrations.

• Redis

  and a job queue (BullMQ or similar): retries, backoff, idempotency, and

  concurrency control.

• Authentication

  and authorization: JWT access and refresh tokens, multi-factor authentication,

  OAuth2 and SSO, and role- or policy-based access control (CASL or similar).

• REST

  API design with OpenAPI (Swagger), and request validation with class-validator

  and class-transformer.

• Unit

  testing with Jest; integration testing with Supertest and Testcontainers or

  equivalent.

• Docker

  and Docker Compose for local development.

Nice to have

• Payments

  or fintech experience: merchant acquiring, ISO and agent models, merchant

  onboarding and underwriting, KYB and KYC, residuals and commissions,

  chargebacks.

• Multi-tenant

  SaaS design, including tenant isolation with PostgreSQL row-level security.

• Socket.IO

  with the Redis adapter.

• PDF

  generation with Puppeteer; streaming Excel, CSV, and XML processing; worker

  threads.

• Schema-driven

  integrations: XSD and JSON Schema, with validation in Ajv.

• Transactional

  outbox and event-driven design; exact decimal arithmetic for financial

  calculations.

• Observability:

  structured logging, correlation IDs with AsyncLocalStorage, metrics, and health

  checks.

• AWS

  container services, Terraform, and GitHub Actions.

• Incremental

  refactoring of large legacy services while raising test coverage.

• Working

  knowledge of Angular, for full-stack contributions.

Candidate Submission Guidelines

• Please submit a CV

  detailing each relevant project, including the start and end dates

  (month and year), role, team size, key responsibilities, and technologies

  used, to help us accurately verify your experience.

• Clearly indicate

  your years of hands-on professional experience with the core

  technology (NestJS), TypeScript, and other

  required technologies relevant to the role.