Staff Application Engineer – Full-Stack Leader

About the role

We are looking for a Staff Application Engineer to own the application layer of CertifyOS, a platform that automates provider licensing, enrollment and credentialing for healthcare organisations. In this senior full-stack role you will define the architecture of both frontend and backend, shape API contracts and drive engineering practices across the team.

Key responsibilities

• Design and evolve the full-stack application layer, including component architecture, state-management strategy and API contract design.
• Define versioning, resource modeling and error-handling for external-facing APIs used by enterprise customers.
• Architect async workflows, optimistic UI patterns and real-time status updates (WebSockets/SSE) for long-running credentialing processes.
• Optimize performance and reliability at the boundary between the data layer (Spanner, BigQuery) and the product, including caching and pagination strategies.
• Integrate AI/LLM capabilities into the product UI while maintaining latency, fallback behavior and observability.

Required profile

• 8+ years of production full-stack engineering experience with proven staff-level technical leadership.
• Track record of setting architectural direction and influencing engineering practices across multiple teams.
• Deep backend expertise in Java (or comparable strongly-typed language) and strong frontend architecture skills in React and TypeScript.
• Experience designing external-facing APIs (REST, GraphQL, gRPC) and handling enterprise integration requirements.
• Ability to communicate technical trade-offs clearly to product and non-technical stakeholders.

Required skills

• Java 21 / Quarkus
• React & TypeScript
• Google Cloud Platform (Spanner, BigQuery)
• Kafka
• REST, GraphQL, gRPC, WebSockets, Server-Sent Events
• Docker & Kubernetes
• GitHub Actions
• Sentry
• AI/LLM tooling (Cursor, Claude Code, Codex)