Senior Full Stack Developer (Node.js / NestJS / Next.js / AI)

Senior Full Stack Developer (Node.js / NestJS / Next.js / AI) Company: CodeQuery (Querycode Techno Private Limited) Location: Patna, Bihar (with projects spanning our Perth, Australia operations) Experience: 2–5+ years (skill matters more than years) Employment Type: Full-time About the Role CodeQuery builds full-stack white-label SaaS platforms for home and field service businesses (the SerQ platform), alongside custom software, digital marketing, and agency services for clients across India and Australia. We're looking for a Senior Full Stack Developer who can independently design, build, and ship production-grade systems—and who's excited to help us push our backend stack from Express toward NestJS as we scale SerQ's multi-tenant, white-label architecture. You'll own features end-to-end, from architecture through deployment, without needing every ticket fully spec'd out for you. What You'll Build Multi-tenant, white-label SaaS modules for the SerQ platform AI-powered tools and internal automation REST APIs and backend services migrating to NestJS Client-facing platforms across home services, healthcare, salon/spa, and field service verticals Payment, maps, and messaging integrations Production deployment pipelines Core Requirements JavaScript & TypeScript Strong grasp of JavaScript fundamentals: closures, async/await, the event loop, prototypes—enough to debug real production issues TypeScript fluency is required (not optional). NestJS only pays off if you actually think in types. Backend – NestJS First We're standardizing new services on NestJS. If you haven't used it before but have strong OOP/dependency injection instincts (e.g., from Spring or Angular), we'll consider you and expect a fast ramp-up. NestJS: modules, providers, dependency injection, guards, interceptors, pipes Solid understanding of OOP, SOLID principles, Clean Architecture, Repository Pattern REST API design, JWT/OAuth, middleware, queues, cron jobs Comfortable reading and refactoring legacy Express code into NestJS modules. This is a real near-term task, not a hypothetical. Frontend React.js Next.js (App Router, SSR/ISR) Database MongoDB or PostgreSQL as a primary database (schema design, indexing, query optimization) Basic Redis for caching and sessions Git & Workflow Real team Git experience: branching, pull requests, rebase, and conflict resolution Deployment Comfortable managing applications on a Linux VPS using Nginx, PM2, SSL, and basic CI/CD with GitHub Actions AI Integration Practical experience calling LLM APIs (OpenAI, Gemini), building agent or tool-calling workflows, and working with structured outputs—not just casual ChatGPT use. Integration Experience Experience with any 2–3 of the following (not all required): Payment gateways: Razorpay, Cashfree, or Stripe Cloud storage: AWS S3 or equivalent Maps and location APIs Firebase (Authentication, FCM) WhatsApp Business API Nice to Have Docker Prisma or Drizzle ORM Prior experience with multi-tenant SaaS, booking systems, CRM, or field-service platforms GraphQL WebSockets Responsibilities Design and build NestJS-based backend services, including migrating select legacy Express modules Develop reusable, performant frontend components in Next.js Design and optimize database schemas across client verticals Integrate third-party APIs (payments, maps, messaging, cloud storage) Build and maintain AI-powered workflows and automations Deploy and maintain applications on production Linux servers Write clean, documented, and testable code while participating in code reviews Collaborate directly with founders, designers, and QA in a small, fast-moving team What We're Evaluating A GitHub profile with real, non-tutorial projects At least one live production application you built end-to-end Ability to explain technical decisions you made and the reasoning behind them—not just list technologies How to Apply Please mention your experience with the following directly in your application: Node.js, NestJS, TypeScript Next.js, React.js MongoDB or PostgreSQL, Redis Any of: Razorpay, Cashfree, AWS S3, Google Maps API, WhatsApp Business API, Firebase Git & GitHub workflow Linux, Nginx, PM2 deployment experience AI agent / LLM API integration experience Links to your GitHub profile and live production applications Share your CV: hr@codequery.in Candidates who can demonstrate real production experience, sound system design judgment, and genuine end-to-end ownership will be prioritized over those who simply list a broad set of tools. Pay: ₹22,000.00 - ₹35,000.00 per month Benefits: Flexible schedule Paid sick time Paid time off Work Location: In person