Senior Software Engineer, Expense

b Overview /b p As an Expense Engineer at Navan, you will help own and ship the end-to-end expense lifecycle for employees, admins, and finance teams. You’ll work across Berlin or London to enhance receipt capture, itemization, policy enforcement, and financial postings at scale, blending backend, frontend, and AI components. You’ll improve accuracy, latency, and safety of AI-powered expense features and collaborate with cross-functional partners to deliver enterprise-grade experiences. This role offers a chance to shape how multinational customers manage expenses, VAT, per diem, and audit-ready data in real time. /p b Responsibilities /b ul li Design and ship backend and web features (Java/Spring Boot, TypeScript) and AI services (Python/TypeScript) /li li Own APIs and event-driven flows for money, receipts, and policy decisions at scale /li li Build or extend LLM-backed agents with tool use, grounding, streaming, memory, and evals /li li Improve document extraction and auto-itemization (tax fields, latency, cost, provider failover) /li li Instrument production with observability, dashboards, and quality metrics /li li Collaborate with Product and Design on employee, admin, and mobile AI surfaces /li li Ensure correctness in financial systems (idempotency, auditability, permissions) /li li Mentor teammates and produce infrastructure-ready designs /li /ul b Key requirements /b ul li 5+ years building production software (8+ for Staff) /li li Strong CS fundamentals /li li Expertise in Java/Spring Boot, modern TypeScript, or Python services /li li Experience with relational data modeling, APIs, and AWS /li li Knowledge of messaging systems (Kafka or similar) is a plus /li li Shipped AI in a real product (LLM APIs, tool calls, retrieval-augmented generation, or document/vision extraction) and understanding of failure modes /li li Comfort with financial or workflow-heavy domains (expenses, payments, ERP, tax) /li li Strong design, code review, CI/CD, observability, and incident ownership /li li Based in Berlin or London or willing to relocate /li li Collaborative across time zones (US, Israel, India) /li /ul ul li collaboration across cross-functional teams /li li strong communication and design documentation /li li mentorship and willingness to share knowledge /li li Java/Spring Boot /li li TypeScript /li li Python /li /ul