Qentelli - MERN Stack Developer - MongoDB/Express.js/React.js

Note : If screened-in, you will be invited for initial rounds on 21st November 2026 (Saturday) in Hyderabad.

Role Overview :

We are looking for a skilled MERN Stack Developer responsible for developing and maintaining scalable web applications using MongoDB, Express.js, React.js and Node.js. The ideal candidate should have strong full-stack development experience, be comfortable working across frontend and backend layers, and contribute to high-quality product delivery in an Agile environment.

Key Responsibilities :

- Hands-on experience with Node.js and Express.js for building scalable backend services and REST APIs

- Solid experience working with MongoDB (schema design, indexing, aggregation pipelines, query optimization)

- Experience designing and developing RESTful APIs and integrating third-party APIs

- Good understanding of authentication & authorization mechanisms (JWT, OAuth, session handling)

- Experience handling API security, exception handling, logging, and performance optimization

- Working knowledge of state management libraries (Redux / Context API)

- Hands-on experience with unit testing frameworks such as Jest / Mocha / Chai

- Experience with Git-based version control workflows

- Ability to work in Agile/Scrum environment and contribute to design, development, and code reviews

- Strong debugging skills and ability to independently handle both UI and API development responsibilities

- Strong experience in JavaScript (ES6+) or TypeScript with hands-on development across frontend and backend layers

Platform-Specific Responsibilities :

- Build Complex Integrations : Design and maintain robust API connections and webhook architectures with legacy POS and reservation systems (e.g., Toast, Lightspeed, ForeUp, OpenTable).

- Develop Embeddable Widgets : Create and optimize lightweight (8KB) cross-origin JavaScript widgets using Vanilla JS/Preact and Shadow DOM for CSS isolation.

- Manage Real-Time Concurrency : Implement Server-Sent Events (SSE) and strict database concurrency controls to prevent race conditions and ensure instant multi-device syncing.

- Architect Payment Flows : Integrate complex payment gateways (Stripe, Fiserv, FreedomPay, Toast Hosted Checkout) handling tokenization, authorization holds, and delayed captures.

- Drive Cloud & DevOps : Establish CI/CD pipelines, automated testing, and active production monitoring within a Microsoft Azure infrastructure.

- Ensure Security & Compliance : Lead API security remediation, implement rate limiting, manage secrets, and uphold SOC2 and GDPR compliance standards. Interface with AI: Connect Node.js backend services with Python-based AI microservices and assist in transitioning the monolith toward a scalable microservices architecture