Full Stack MERN Developer

Workana is the largest remote work platform for talents in Latin America. Our Workana Premium segment focuses on connecting exceptional professionals with leading companies around the world, offering competitive compensation, dedicated support, and the flexibility of remote work. We are pleased to present the following opportunity. About Our Client OurOffice is a U.S.-based SaaS startup developing technology solutions for organizations that need secure, scalable, and reliable software. The company is seeking a senior-level Full Stack MERN Developer to work directly with its hands-on CTO and take ownership of complex production systems. The ideal candidate will be comfortable working across the frontend, backend, database, integrations, and AWS infrastructure. A key initiative for this role is the development of a secure Data Export and Analytics API that will allow external platforms, including Microsoft Power BI, to access organization-scoped SaaS data efficiently and securely. Role Overview As a Full Stack MERN Developer, you will maintain and scale an established MERN application while building new features and improving the platform’s security, performance, reliability, and observability. You will be responsible for designing and implementing secure multi-tenant APIs, large-data processing workflows, integrations with third-party services, and end-to-end product features using React, Redux, Node.js, Express, MongoDB, and AWS. This is a long-term remote opportunity for a senior or expert engineer based in Latin America who can work during U.S. West Coast business hours and communicate fluently in English. Responsibilities Maintain, debug, and scale a production MERN application. Build secure Data Export and Analytics APIs for Microsoft Power BI and other external systems. Design large-data workflows using MongoDB cursors, batching, Node.js streams, CSV exports, and Amazon S3. Implement secure multi-tenant access with authentication, authorization, API credentials, rate limiting, and strict organization-level data isolation. Design and optimize MongoDB and Mongoose schemas, indexes, aggregation pipelines, Atlas Search configurations, and database queries. Analyze query performance using tools such as explain() and implement appropriate optimization strategies. Build reliable asynchronous workflows with concurrency controls, retries, idempotency, leases, locks, timeouts, and failure recovery. Develop new features end-to-end across React, Redux, Node.js, and Express. Integrate and maintain third-party services, including AI/NLP tools, Twilio, SendGrid, Stripe, Microsoft services, Slack, and AWS services. Improve application performance, security, reliability, logging, monitoring, and observability. Investigate and resolve production issues in a large, established application. Collaborate directly with the CTO to define technical solutions, prioritize work, and deliver reliable production features. Contribute to technical…