About Scalepex Scalepex is a nearshore partner that empowers businesses to scale efficiently and effectively through exceptional services. With a strong focus on customer success, innovation, and cultural alignment, we support companies in building high-performing teams across industries. At Scalepex, we believe in fostering an environment where our people can thrive, grow their careers, and make a real impact. Job Summary We are looking for a Senior Full Stack Engineer to join a fast-growing B2B SaaS startup building a modern multi-tenant platform that automates financial and operational workflows. This is a highly autonomous role where you'll own core platform development, backend architecture, database design, integrations, and platform scalability. You'll work in an AI-native engineering environment, leveraging modern AI coding tools to deliver high-quality software quickly. Requirements Responsibilities Design, develop, and maintain scalable backend services using Node.js and TypeScript. Own PostgreSQL database architecture, schema design, migrations, and performance optimization. Build and maintain REST APIs, OAuth integrations, and third-party platform connections. Develop and improve multi-tenant SaaS infrastructure. Create reliable background jobs, schedulers, and asynchronous workflows. Write automated unit and end-to-end tests. Audit existing systems and propose scalable technical solutions. Improve application reliability, performance, and security. Collaborate with the team during US business hours. Leverage AI-assisted development tools to increase development speed while maintaining high quality. Must Have 5+ years of Full Stack or Backend software development experience. Expert knowledge of TypeScript and JavaScript. Strong experience with Node.js. Experience with Next.js (App Router). Advanced PostgreSQL knowledge: Schema design Raw SQL Query optimization Database migrations Experience using Prisma ORM (or similar ORM). Experience building scalable SaaS applications. Multi-tenant architecture experience. Experience building REST APIs. OAuth 2.0 and Webhooks. Playwright or Puppeteer. Background job schedulers (Cron, BullMQ, pg-boss or similar). Automated testing experience. Git and Pull Request workflows. Excellent written English. Availability during US business hours. Nice to Have Experience working with financial systems. React 19. Python. Linux, Nginx, PM2. CI/CD pipelines. PgBouncer. Experience with Model Context Protocol (MCP). Experience with Cursor, Claude Code, Copilot, or similar AI development tools. Benefits Contractor scheme 100% Remote