Role Overview

We are looking for a Senior Full Stack Engineer with strong backend-first fundamentals and mandatory frontend expertise, who can build and scale AI-powered product features for a Contact Center as a Service (CCaaS) platform.

This role follows a backend-first evaluation model: candidates must demonstrate strong backend fundamentals (API design, Kafka, system design) as a gating requirement before frontend and AI depth are evaluated. Frontend expertise is mandatory for the role and will be assessed once backend fundamentals are cleared.

Hands-on experience building production AI features is required, not just theoretical exposure.

Key Responsibilities

Design and build robust REST APIs with correct HTTP semantics and idempotency handling Develop backend services using NestJS with clean modular design and effective dependency injection Design systems with performance and scalability in mind (caching, indexing, horizontal scaling) Work with Postgres to design schemas, write efficient queries, and optimize performance Implement and maintain Kafka-based asynchronous workflows Make pragmatic architectural decisions and avoid unnecessary complexity Clearly document and explain end-to-end backend flows and system designs Collaborate with cross-functional teams to deliver reliable backend solutions

Required Skills (Must-Have)

Backend Fundamentals (Primary Gating Skills)

Strong experience designing RESTful APIs with correct HTTP semantics Clear and practical understanding of idempotency, retries, and failure handling Strong backend system design skills with ability to explain end-to-end flows

Messaging & Scalability

Hands-on experience with Kafka (producers, consumers, partitions, consumer groups) Understanding of scalability, throughput, ordering, retries, and DLQs

Frontend (Mandatory)

Strong experience building frontend applications using React.js (or similar frameworks) Ability to design and implement frontend-backend contracts Experience building real-time or AI-assisted user interfaces Comfort working across the full stack, owning features end to end

Backend Framework & Database

Strong experience with Node.js, TypeScript, and NestJS Deep understanding of Dependency Injection and clean modular design Hands-on experience with Postgres, including schema design and indexing

AI / RAG Experience (Required)

Hands-on experience building production-grade AI features Practical understanding of RAG architectures and vector databases Experience integrating with LLM providers (OpenAI, Azure OpenAI, AWS Bedrock, etc.) Understanding of prompt design, prompt lifecycle management, and evaluation Ability to reason about latency, cost, accuracy, and reliability trade-offs in AI systems

What We Value

Pragmatic problem-solving over theoretical answers Clarity of thought and communication Ability to simplify complex problems Hands-on experience and real-world decision making

What Will Not Work in This Role

Purely theoretical or textbook-level knowledge Over-engineered or generic system designs Inability to explain architectural decisions clearly Reliance on scripted or AI-generated answers without practical depth

 

Ideal Candidate Profile

A senior backend engineer who:

Has built and scaled real backend systems Thinks about correctness, performance, and simplicity by default Communicates clearly and concisely Makes informed trade-offs and converges quickly on workable solutions

Interview Focus Areas

Backend fundamentals: REST API design, idempotency, system design Kafka fundamentals and scalability concepts Architectural clarity and problem-solving approach Frontend fundamentals (React, UI architecture, frontend-backend contracts) Hands-on AI implementation experience and design reasoning