Backend 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

Roles and Responsibilities

• Develop and manage highly trafficked, highly scalable web properties with PHP5 using Laravel/ZEND CodeIgniter/Yii/Symfony framework.
• Understand the specifications to define system requirements.
• Collaborate and communicate project updates and progress to team members and clients.
• Analyze, design, code, debug, test, document and deploy changes to the system.

• Build efficient, testable, and reusable PHP modules
• Write all clean object-oriented PHP as well as efficient SQL
• Integrate features and improvements that can support our large-and-growing SAAS product.
• Take initiative and contribute to technical solutions, R&D.
• Contribute to internal tools/processes that help us manage the product and QA cycle
• Perform Unit testing.
• Opportunity to learn and work on interesting solutions like Application Scaling, Microservices, Batch Processing, Javascript frameworks like ReactJS.
• Keep abreast of new trends and best practices in web development
• Adhere to milestones assigned

Skills:

• Must require solid programming proficiency with Core PHP.
• Strong knowledge of OOPS and how to apply it in application code is a must.
• Basic understanding of front-end technologies, such as JavaScript, HTML5, and CSS3
• Familiarity with SQL databases and their declarative query languages.
• Exposure to designing and building APIs (REST/HTTP/Soap) is highly preferred.
• Understanding the fully synchronous behavior of PHP
• Experience with any MVC framework is an added advantage.
• Proficient understanding of software testing
• Understanding of code versioning tools, such as Bitbucket, Git is an advantage
• Understanding of product development environments and methodologies like Agile highly preferred
• Good problem-solving skills.

Desired Profile:

• Minimum 1.5 years of experience developing web applications and understanding modern PHP standards.
• The candidate should be willing to work with a startup/mid-size company.
• The candidate must love to code and must possess a thorough knowledge of web technologies.
• Motivated and ambitious to learn new technologies, grow as a leader in quick time.
• Good communication skills - must be able to explain work and provide answers in English

• Relevant Experience : Minimum 2 Years
• You have prior experience developing and working on consumer facing web/app products
• Hands-on experience on Python. Exceptions can be made if you’re really good on any other language with experience on building web/app based tech products
• Experience in at least one of the following frameworks - Django, Flask, Falcon, web2py, Twisted, Tornado
• Working knowledge of MySQL, MongoDB, Redis
• Good understanding of Data Structures, Algorithms and Operating Systems
• You've worked with core AWS services in the past and have experience with EC2, ELB, AutoScaling, CloudFront, S3
• You can dabble in Frontend codebases using HTML, CSS and Javascript
• You love doing things efficiently. At Fynd, the work you do will have a disproportionate impact on the business. We believe in systems and processes that let us scale our impact to be larger than ourselves
• You might not have experience with all the tools that we use but you can learn those given the guidance and resources