Senior Backend Engineer

Node.js, System Design & Production Platforms

Mumbai (On-site) | Full-time | 5+ years

About the role

Unico Connect is an AI-first technology partner that builds custom mobile, web, and AI products for clients across multiple geographies. We are hiring a Senior Backend Engineer who will own the backend architecture of complex production platforms across customer engagements, from API design and data modelling to multi-tenancy, workflow orchestration, and deployment automation.

The mandatory requirement for this role is hands-on production experience as a senior backend engineer building complex, scalable systems in Node.js, with end-to-end ownership of architecture, data, and operations on at least one live customer platform. The role is hands-on and architectural. Expect to design system architecture, lead a small group of backend engineers, build the hardest parts yourself, set engineering standards, and partner closely with frontend, AI, and DevOps engineers.

A typical week includes an architecture decision on a new service, hands-on implementation of a critical path, a code review with mid-level engineers, and a working session with the AI engineer on an integration contract.

Responsibilities

• System architecture: Own the backend architecture across customer engagements. Make and document decisions on service boundaries, data models, API contracts, deployment topology, and trade-offs.
• Hands-on backend delivery: Lead by example on complex modules, performance-critical paths, and high-risk areas using Node.js (Express, NestJS, Fastify) with TypeScript. Pick up Python (FastAPI) where engagements require it.
• Database design and performance: Drive PostgreSQL schema design, indexing strategy, query optimisation, migrations, and capacity planning. Set the data modelling standard across the pod.
• Caching, queues, and workflows: Design caching strategies (Redis), event-driven patterns (Kafka, RabbitMQ, SQS, NATS), and long-running workflow orchestration (Temporal, BullMQ, Celery, or equivalent). Handle retries, idempotency, and failure recovery.
• Multi-tenancy and platform patterns: Design and implement multi-tenant data isolation, RBAC, audit logging, and resource quotas appropriate to enterprise-grade products.
• API and integration design: Set the standard for REST, GraphQL, and gRPC contracts. Drive versioning, authentication (OAuth, JWT, SSO), security-by-default, and developer ergonomics.
• Observability and operations: Instrument services with OpenTelemetry, Prometheus, and Grafana. Define SLOs, lead incident response, and write postmortems.
• Code quality and mentorship: Run code reviews, define conventions, mentor mid-level engineers, and raise the engineering bar.
• AI-assisted engineering discipline: Use Claude, Cursor, and similar tools day to day. Set the team standard for prompts, patterns, AI-assisted review, and validation of AI-generated backend code.
• Client engagement: Represent Unico Connect in technical conversations with customers. Defend architectural decisions, communicate trade-offs, and manage scope with stakeholders.

Requirements

• Hands-on production experience as a senior or lead backend engineer in Node.js (mandatory). Must have personally built and shipped complex production systems in Node.js, owning architecture, data, and operations on at least one live customer or platform engagement. POCs and internal tools alone do not qualify.
• 5+ years of professional backend engineering experience, with at least 1 to 2 years in a senior or lead role with direct responsibility for technical decisions and team output.
• Deep Node.js and TypeScript proficiency. Strong with Express, NestJS, or Fastify. Comfort with async patterns, streams, worker threads, and performance profiling.
• Python as a strong plus. Hands-on production experience with FastAPI, Django, or Flask is a meaningful advantage. Willingness and demonstrated ability to pick up Python as engagements demand is required.
• PostgreSQL depth. Schema design, normalisation, indexing, query performance, migrations, and at least one production system where you owned the data model end to end.
• Caching and event-driven architecture. Hands-on with Redis (or equivalent) for caching and session management, and message queues or event-driven patterns (RabbitMQ, SQS, Kafka, NATS) for asynchronous workflows.
• AWS depth. Hands-on production experience with EC2, S3, RDS, IAM, VPC, ECR, and at least one of EKS, ECS, or Lambda. Comfort owning deployment, monitoring, and cost.
• System design and end-to-end ownership. Able to take an ambiguous problem, break it into components, evaluate alternatives, produce an architecture that holds up under review and load, plan execution, and ship to production with limited supervision.
• AI-assisted engineering experience. Daily use of Claude, Cursor, Copilot, or equivalent in production work. Strong discipline for reviewing, testing, and validating AI-generated backend code.
• Excellent written and spoken English, with experience working directly with international clients. Confident defending architectural choices in writing and in review.



Nice to have: workflow orchestration (Temporal, Airflow); GraphQL (Apollo, gRPC); sandboxed execution environments; experience building developer platforms or multi-tenant SaaS; OpenTelemetry instrumentation; prior agency or consulting experience.