Staff Application Engineer

CertifyOS

About The Position

CertifyOS is building the data infrastructure that powers modern healthcare. Today, healthcare organizations rely on fragmented and outdated provider data. This creates unnecessary administrative work, regulatory risk, and higher costs across the system. We’re solving that problem. Our API-first platform automates provider licensing, enrollment, credentialing, and network monitoring by connecting directly to hundreds of primary data sources. We help healthcare organizations maintain accurate, compliant, and reliable provider networks at scale. Our vision is simple: One API. One provider ID. Frictionless provider data. We’re backed by leading investors and built by a team with deep experience in provider data systems. At CertifyOS, we value authenticity, accountability, collaboration, results, and openness to feedback. We’re building a high-ownership team focused on solving real infrastructure problems that impact millions of patients. About the Role We’re looking for a Staff Software Engineer to own the application layer of the CertifyOS platform the full-stack systems that translate our provider data infrastructure into products that payers, health systems, and digital health companies actually use. This is a Staff-level role with real architectural scope. You won’t be handed a spec you’ll define how the application layer is structured, how the frontend and backend evolve together, how API contracts are designed for external consumers, and how the engineering practices that govern application development scale with the team. You’ll drive technical strategy, shape engineering culture, and set patterns that other engineers build on.

Requirements

Staff-level ownership & technical leadership
8+ years building production full-stack systems, with demonstrated impact at Staff or Tech Lead level
Track record of setting technical direction (defined architecture others built on)
Proven ability to influence engineering practices across teams without direct authority (design docs, code review, technical credibility)
Experience leading cross-functional technical initiatives involving product, design, and backend engineering simultaneously
Deep backend expertise in Java or a comparable strongly-typed language (service design, API contract modeling, performance optimization, reliability engineering)
Strong frontend architecture skills in React and TypeScript (component system design, state management at scale, build tooling, rendering tradeoffs)
Experience designing and evolving external-facing APIs under active consumers (versioning, backward compatibility, error semantics, developer experience)
Fluency across API paradigms (REST, GraphQL, gRPC, WebSockets, SSE) and the judgment to choose the right one
Experience building application layers for enterprise B2B products (multi-tenancy, role-based access control, audit logging, PHI/PII compliance)
Experience with async workflow patterns in product UIs (long-running jobs, real-time status, optimistic updates)
Understanding of SOA and microservices boundaries from an application perspective (designed service contracts, managed coupling and versioning tradeoffs)
Strong instincts for application-layer performance (caching strategy, pagination design, N+1 query patterns)
Experience defining and owning SLOs for user-facing systems (TTFB, interaction latency, error rates)
Experience building observability into application systems (distributed tracing, structured logging, frontend error tracking)
Experience integrating AI/LLM capabilities into production application layers (streaming UX, latency handling, fallback behavior, eval instrumentation)
Fluency with AI-assisted development tools (Cursor, Claude Code, MCP servers)
Strong written communication (design docs that create alignment)
Track record of growing engineers around you

Nice To Haves

Experience with microfrontend architectures or design system libraries at scale
Familiarity with healthcare data standards (FHIR, HL7) or credentialing and enrollment workflows
Experience with feature flagging, A/B testing infrastructure, or progressive rollout patterns
Familiarity with accessibility standards (WCAG) in enterprise product contexts
Experience with cost optimization for cloud-native application deployments
Track record of reducing frontend or backend technical debt through iterative architecture migration

Responsibilities

Own the application layer of the CertifyOS platform, including full-stack systems.
Define the structure of the application layer, frontend/backend evolution, and API contract design for external consumers.
Scale engineering practices for application development.
Drive technical strategy and shape engineering culture.
Set patterns for other engineers to build upon.
Build a frontend that scales with product complexity without becoming unmaintainable.
Design systems, state management strategy, API contract alignment between frontend and backend, and component architecture.
Design API contracts that serve both internal product teams and external enterprise consumers.
Define versioning strategy, resource modeling, error semantics, and pagination patterns for external-facing APIs.
Architect application patterns (optimistic UI, async job tracking, real-time status updates) for enterprise product experiences on top of complex, async data workflows.
Own the performance boundary between the data layer and the product, managing query latency, pagination strategy, and caching architecture.
Define how AI-powered capabilities integrate into the application layer, including latency handling, fallback behavior, streaming UX patterns, and eval instrumentation.
Integrate AI/LLM capabilities into production application layers.
Grow engineers through code review, pairing, and technical mentorship.
Represent technical tradeoffs clearly to product and non-technical stakeholders.