Responsibilities: Maintain and enhance the backend services powering the SaaS platform (Node.js/Express/NestJS with TypeScript). Ensure uptime, scalability, and performance of APIs handling campaign generation, template storage, and credit-based billing. Optimize MongoDB queries, indexes, and caching strategies for high-performance APIs. Implement and manage Redis, job queues, and async workflows. Monitor and maintain AWS infrastructure: EC2, S3, CloudWatch, Lambda, SES. Implement security best practices: API authentication, rate-limiting, GDPR compliance, email data handling. Maintain API versioning and documentation (OpenAPI/Swagger). Write unit and integration tests to ensure code quality and reliability. Debug and resolve complex production issues efficiently. Required Skills: Strong proficiency in Node.js with TypeScript (Express.js or NestJS). Experience with MongoDB, schema design, and ORMs (Mongoose, Prisma). Experience with Redis (pub/sub, caching) and job queues (BullMQ/RabbitMQ). Familiarity with AWS services: EC2, S3, CloudWatch, SES, Lambda. Dockerized microservices and CI/CD pipelines (GitHub Actions, or similar). Knowledge of authentication & authorization (JWT, OAuth2, role-based access). Basic Logging & monitoring experience (Winston, Pino, Prometheus/Grafana). Unit & integration testing experience (Jest, Mocha, Vitest). Knowledge of email compliance tools (SpamAssassin, DKIM/SPF/DMARC) is a plus. Experience: 3–5 years in backend development. Prior experience in SaaS applications, high-traffic APIs, or campaign/marketing platforms is preferred.