Full Stack Developer

Job Title: Full Stack Developer Company: E PAYMENT SERVICES L.L.C Job Category: MERN Roles & Responsibilities: The candidate will work closely with product, backend, frontend, DevOps, and QA teams to design, develop, integrate, test, and maintain reliable production\-grade applications. Key ResponsibilitiesFull Stack Development * Develop responsive and scalable web applications using React.js, Node.js, Express.js, and JavaScript/TypeScript. * Build reusable and maintainable frontend components. * Develop secure and scalable RESTful APIs and backend services. * Implement authentication, authorization, RBAC, session management, and API security. * Integrate frontend applications with backend APIs and third\-party services. * Troubleshoot and optimize application performance. Database Development * Work with MongoDB and PostgreSQL for application development. * Design database schemas, relationships, indexes, and queries. * Write optimized SQL queries and MongoDB queries. * Handle transactions, data consistency, migrations, and database optimization. * Troubleshoot database performance and connectivity issues. * Deploy and maintain applications on AWS. * Hands\-on experience with services such as: * EC2 * ECS * ECR * S3 * RDS * CloudWatch * IAM * VPC * ALB * Route 53 * Understand basic cloud networking, security groups, IAM permissions, and environment configuration. * Work with development, staging, and production environments. * Support CI/CD pipelines and automated deployments. * Develop and integrate payment gateways and payment APIs. * Understand payment flows such as: * Payment initiation * Authorization * Capture * Success/failure handling * Refunds * Webhooks * Transaction reconciliation * Work with payment gateway APIs, SDKs, webhooks, and third\-party payment providers. * Implement secure handling of payment\-related data. * Troubleshoot payment API and transaction integration issues. * Understanding of payment orchestration, routing, or payment processing systems is an advantage. * Design and consume REST APIs. * Integrate external services and third\-party APIs. * Implement webhook\-based integrations. * Handle API authentication, retries, errors, rate limits, and logging. * Document APIs using Swagger/OpenAPI or similar tools. * Follow secure coding practices. * Implement proper input validation and error handling. * Protect APIs against common vulnerabilities such as SQL injection, NoSQL injection, XSS, CSRF, and unauthorized access. * Optimize frontend and backend performance. * Implement logging, monitoring, and proper exception handling. * Work with developers, DevOps engineers, QA engineers, and product teams. * Participate in code reviews and technical discussions. * Analyze requirements and convert them into technical solutions. * Debug production issues and provide root\-cause analysis. * Maintain clean, documented, and maintainable code. * React.js * JavaScript / TypeScript * HTML5 * CSS3 * REST API integration * State management such as Redux, Context API, or similar * Node.js * Express.js * TypeScript * REST API development * Authentication \& Authorization * JWT * Webhooks * Strong problem\-solving and debugging skills. * Good understanding of software development lifecycle. * Ability to write clean, scalable, and maintainable code. * Good understanding of API architecture and database design. * Ability to work independently as well as within a team. * Strong attention to security, performance, and reliability. * Willingness to learn and work with new technologies. * Good communication and documentation skills. * JavaScript / TypeScript fundamentals * React.js development * Node.js and Express.js * REST API architecture * MongoDB and PostgreSQL * AWS fundamentals * Docker and deployment concepts * Payment gateway integrations * Webhooks and transaction lifecycle * AI/LLM integration * Application security * Debugging and production troubleshooting * System design fundamentals * Git and development workflow * Real\-world coding/problem\-solving ability Work Location: Hybrid remote in Mumbai, Maharashtra (Mumbai, Mumbai District) Work Location: Maharashtra, India Availability: Full time

Experience working with AI\-powered features and payment gateway/payment processing systems will be highly preferred. * Integrate AI/LLM\-powered features into web applications. * Work with AI APIs and third\-party AI services. * Build features such as AI assistants, intelligent search, automation, recommendations, or AI\-based analytics. * Understand basic concepts such as: * LLMs * Prompt engineering * Embeddings * RAG * Vector databases * AI API integration * Experience with OpenAI, Claude, Gemini, Qwen, Ollama, or similar technologies is a plus. Required Technical SkillsFrontend * Payment gateway API integration * Payment webhooks * Transaction lifecycle * Refunds * Reconciliation * Payment failure handling * Experience with providers such as Stripe, Razorpay, PayPal, Adyen, Checkout.com, or similar is an advantage. * Experience with payment platforms, fintech, banking, or financial applications. * Understanding of PCI DSS and payment security. * Experience with payment orchestration or multi\-provider payment systems. * Experience working with microservices. * Docker and containerization. * Redis or caching technologies. * Message queues such as RabbitMQ, Kafka, or SQS. * Basic understanding of AWS networking and security. * Experience with automated testing. * Experience troubleshooting production systems. Education * Bachelor's degree in Computer Science, Information Technology, Engineering, or a related field is preferred. * Equivalent practical development experience will also be considered. Experience Level Interview Focus Areas Benefits: Key Skills: MERN Stack, MongoDB, Express.js, React.js, Node.js, JavaScript, REST API, Git, GitHub, TypeScript, SQL Salary: INR 380819 - 1.03522e+06 per yearly