Senior Full Stack Engineer – Base44, OAuth & API Integration Systems

We are looking for a senior full stack engineer with strong experience in Base44, API integrations, Google OAuth 2.0, and production-grade SaaS systems to help extend and stabilize an existing creator-focused platform. This role requires someone comfortable working directly inside a Base44/configuration-driven environment while also handling backend integrations, synchronization systems, and full-stack application updates. This is primarily an integration and backend architecture role with some React/full-stack platform work as needed. What You'll Work On -Google OAuth 2.0 authentication and secure account linking -Scheduled sync and ingestion workflows -Token lifecycle management and refresh handling -API quota optimization and rate-limit handling -Data/entity mapping between external APIs and internal systems -Production stability improvements and error recovery flows -Extending existing React/full-stack application workflows -Working directly inside a Base44 environment and configuration-driven platform structure Required Experience -Strong Base44 experience -Google OAuth 2.0 experience -React and modern full-stack development -API integration and backend architecture -Background jobs, queues, or scheduled processing systems -Production SaaS environments -Error handling, retries, and operational reliability -Experience working inside existing codebases and systems Nice to Have -Node.js / TypeScript backend experience -Analytics platform integrations -Experience with scalable ingestion pipelines -Experience with configuration-driven or low-code platforms Please Include -Relevant Base44 projects or experience -Relevant OAuth projects -Sync workflow experience -Preferred backend stack -Availability in US timezone -Timeline and budget