Node.JS Developer

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 to own the backend architecture of a complex production AI platform on a dedicated client engagement: API design and data modelling, multi-tenancy, orchestration of long-running agent workloads, and the services that manage user projects and generated output.

We are open to full stack engineers whose primary strength and interest is backend. If you have shipped full stack work but the backend is where you do your deepest engineering, you are a fit for this role.

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 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 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, query optimisation, migrations, and capacity planning.

Set the data-modelling standard across the pod.

Caching, Queues, and Workflows

Design caching (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.

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 engagement.

Full stack engineers whose deepest work is on the backend qualify.

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) and message queues or event-driven patterns (RabbitMQ, SQS, Kafka, NATS).

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 with limited supervision.

AI-Assisted Engineering Experience

Daily use of Claude, Cursor, Copilot, or equivalent.

Strong discipline for reviewing and validating AI-generated backend code.

Excellent Written and Spoken English

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
• Multi-tenant SaaS experience
• OpenTelemetry instrumentation
• Prior agency or consulting experience

Backend Developers

• Contract To Hire (Initial Engagement: 6 months)

Experience: 5+ years

Mandatory Skills:

● Node.js

● Python

● MongoDB

● PostgreSQL

● REST API design and development

● Backend architecture and service design

● Database design, indexing and query optimisation

● Performance tuning

● Authentication/authorisation

● Third-party integrations

● Asynchronous processing and background jobs

● Logging, monitoring and debugging

● Git and collaborative development

● Scalable, maintainable and testable backend services

● Architecture discussions, code reviews, debugging and production support

Good to have:

● Microservices

● Docker

● Cloud platforms

● Redis

● Message queues

● CI/CD

● Observability

• Experience in Spring Boot, Jenkins, Git, Hibernate, Kubernetes, and Docker
•  Experience in the development of scalable and extensible systems using Java
•  Proficiency in Database technology such as MySQL, Oracle, and MongoDB
• Routines Sync & Async
• Solid and fluent understanding of algorithms and data structures
• Excellent software design, problem-solving and debugging skills
• Demonstrated high ownership in previous projects
• Excellent Communication Skills"

We’re seeking a Back-End Developer with hands-on experience in Node.js or any other modern backend framework. You’ll be responsible for building robust, scalable APIs and server-side logic powering Zilo’s high-velocity quick commerce platform.

Key Responsibilities

Develop, maintain, and optimize back-end applications and APIs.

Work on microservices, API integrations, and data modeling.

Ensure system scalability, reliability, and performance under high traffic.

Collaborate with front-end and mobile developers for seamless API integration.

Implement best practices in code quality, security, and database design.

Troubleshoot production issues and support deployment cycles.

Technical Skills Required

Strong proficiency in Node.js, Express.js, or similar backend frameworks.

Experience in MongoDB, MySQL, or PostgreSQL.

Understanding of RESTful APIs, authentication (JWT/OAuth), and middleware.

Familiarity with AWS, Docker, or other deployment environments.

Hands-on experience with Git and CI/CD pipelines.

Knowledge of other programming languages like Python, Java, or Go is an added advantage.

Key Responsibilities: 

• Rewrite existing APIs in NodeJS. 
• Remodel the APIs into Micro services-based architecture. 
• Implement a caching layer wherever possible. 
• Optimize the API for high performance and scalability. 
• Write unit tests for API Testing.
• Automate the code testing and deployment process.

Skills Required: 

• At least 3 years of experience developing Backends using NodeJS — should be well versed with its asynchronous nature & event loop, and know its quirks and workarounds. 
• Excellent hands-on experience using MySQL or any other SQL Database. 
• Good knowledge of MongoDB or any other NoSQL Database. 
• Good knowledge of Redis, its data types, and their use cases. 
• Experience with graph-based databases like GraphQL and Neo4j. 
• Experience developing and deploying REST APIs. 
• Good knowledge of Unit Testing and available Test Frameworks. 
• Good understanding of advanced JS libraries and frameworks. 
• Experience with Web sockets, Service Workers, and Web Push Notifications. 
• Familiar with NodeJS profiling tools. 
• Proficient understanding of code versioning tools such as Git. 
• Good knowledge of creating and maintaining DevOps infrastructure on cloud platforms. 
• Should be a fast learner and a go-getter — without any fear of trying out new things Preferences. 
• Experience building a large-scale social or location-based app.

Role description:

We are looking for a LEAD- Fullstack with expertise and experience in designing and developing applications including new developments, enhancements, maintenance and support. The role involves continuous collaboration with team, partners.

Candidate description:

Should have:

• Passion for technology and financial domain with demonstrated ability to learn quickly
• Delivery focus with ability to take full ownership
• Strong commitment to quality and delivery
• Strong communication skills

Skills/Knowledge and experience:

• Object oriented design and development skill
• Webservices - Node JS/Express JS, Rest API
• Frontend –, React, Angular (Javascript and Typescript)
• Unix and Shell scripting
• SQL Proficiency, good to know MongoDB

ROLES AND RESPONSIBILITIES 

• Proven working experience in backend app development and experience with Node JS.  
• Build advanced ecommerce backend applications for the multiple client platforms (both React and Android).  
• Understanding of design principles and good architecture patterns.  
• Proper Data Structures and Algorithm knowledge is a must.  

• Graph QL and Apollo Server knowledge.  
• Collaborate with cross-functional teams to define, design, and ship new features. Work with outside data sources and APIs like the one of Unicommerce.  
• Create Unit-test code for robustness, including edge cases, usability, and general reliability.  
• Work on bug fixing and improving application performance.  
• Continuously discover, evaluate, and implement new technologies to maximize development efficiency.  

• Translate designs and wireframes into high quality code.  
• Have a good understanding of CI/CD tools (any).  
• Robust knowledge of popular databases like MongoDB, Elastic Search, DynamoDB, Redis etc;  
• Knowledge about AWS Services like EC2, Lambda, Kinesis, Redshift, S3 is super plus. 
•  

CANDIDATES MUST HAVE  

• Node JS. 
• Data Structures and Algorithm  
• HTML5 and CSS3 
• Graph QL and Apollo Server  
• MongoDB, Elastic Search, DynamoDB, Redis 

• AWS Services like EC2, Lambda, Kinesis, Redshift, S3  

REQUIREMENTS  

• Bachelor's degree in computer science, information science, or similar.  
• Extensive knowledge of JavaScript, web stacks, libraries, and frameworks.  
• Knowledge of front-end technologies such as HTML5 and CSS3.  

• Superb interpersonal, communication, and collaboration skills.  
• Exceptional analytical and problem-solving aptitude.  
• Great organisational and time management skills.  
• Availability to resolve urgent web application issues outside of business hours