Senior/ Staff Backend Software Engineer

At ExpiWell, we are transforming how organizations gather real‑time, in‑the‑moment insights about human experiences. Our Experience Sampling Methodology (ESM) platform and mobile apps replace outdated survey methods, allowing organizations to capture dynamic and contextual data. Trusted by leaders in HR, Product & CX, Healthcare, and Academia, ExpiWell enables the collection of engagement, emotion, and behavior information through geofencing‑triggered surveys and multimedia data capture. We aim to enhance research and promote a greater understanding of the human condition. Position Overview We’re seeking an experienced Senior Backend developer to modernize and extend our ExpiWell research platform API using NestJS and Apollo GraphQL, AWS and MongoDB Atlas architecture. The main server will serve a native iOS and Android application as well as a modern unified React Native app that is currently in development. Key Responsibilities Migrate legacy API endpoints from Express to NestJS v11 with full TypeScript typing. Build RESTful APIs, WebSocket gateways, and background job systems. Improve AWS infrastructure to a more modern VPS. AWS certification a huge plus. Redesign our MongoDB architecture to better align with global customers. Complete Apollo GraphQL certificate training in Parts 1 to 4 (must complete). Implement authentication, payment processing, and real‑time messaging features. Write comprehensive unit tests (Jest) and maintain >80% code coverage. Design and document APIs using Swagger/OpenAPI specifications. Review and validate AI‑generated code for quality, security, and best practices. Implement AWS integrations (S3, SES) and third‑party services (SendGrid, Stripe, Twilio). Required Skills Expert‑level NestJS (v11+) with dependency injection, guards, interceptors, pipes. Advanced TypeScript (v5.7+) with generics, decorators, and type safety patterns. Apollo GraphQL basic 1‑4 certificate training. Free training provided by Apollo Odyssey. MongoDB with Mongoose ODM and complex aggregations. Testing: Jest, unit testing, E2E testing, test coverage strategies. RESTful API design and versioning strategies. WebSocket/Socket.IO for real‑time features. AWS Services: S3, SES, CloudWatch. Git workflow with conventional commits and PR reviews. AI‑Assisted Development Experience using AI coding assistants (Claude, VSCode CLI). Ability to write effective prompts for code generation. Strong code review skills to validate AI‑generated code. Understanding of when to trust AI vs. manual implementation. Familiarity with AI‑assisted testing and documentation. Nice to Have Redis for caching and distributed locking. Stripe payment integration. Sentry error monitoring. Docker containerization. Experience with research/survey platforms. What Makes You Great for This Role You can rapidly prototype features using AI assistance while maintaining code quality. You understand modern backend architecture (microservices, event‑driven, CQRS). You write clean, maintainable code that follows SOLID principles. You're comfortable working with large codebases and legacy migration. You proactively write tests and documentation. You can debug complex issues across multiple services. Project Context You’ll be working on a research platform that powers mobile experience sampling studies. The API handles: Survey delivery and response collection, Real‑time participant messaging, Media upload and transcription, Geofencing and sensor triggers, Anonymous survey participation. Framework: NestJS v11 monorepo with shared libraries, Package Manager: pnpm, Testing: Jest v30 with coverage reporting, Deployment: AWS infrastructure. How to Apply Resume highlighting NestJS and TypeScript projects. GitHub and LinkedIn profile. Brief description of your experience with AI coding tools. What We Offer Fully remote, flexible work setup. Supportive, collaborative global team. Opportunities for long‑term growth and increased responsibility. Referrals increase your chances of interviewing at ExpiWell by 2x. Seniority level Mid‑Senior level Employment type Full‑time Job function Engineering and Information Technology Software Development #J-18808-Ljbffr