Senior Software Engineer, Expense

Navan (Nasdaq: NAVN) is the AI-powered business travel, payments, and expense platform that makes it easy to book, pay, and close the books. Expense is a core part of that story: from the moment a receipt is captured to the moment it lands in the general ledger.

About the Role

We are growing Expense Engineering in Berlin and London. You will join the org that owns the full expense lifecycle for employees, approvers, and finance admins — used by companies worldwide, including complex EMEA tax, VAT, per diem, mileage, and multi-entity setups. You will ship in the same systems that already run receipt intelligence, conversational expense capture, missing-info assistants, and admin automation.

What You'll Work On

The expense product, end to end: employee flows (transaction entry, drafts, receipts, trips, reimbursements, cards, bank-linked spend); international spend (line-itemization, per diem, mileage, VAT/GST, tax receipts); admin and control (policy, approvals, custom and HR fields, audit logs, reporting); money movement and close (statements, purchase cards, reimbursements, accounting postings).

AI that is already in the product: receipt intelligence (extract merchant, amount, date, tax, and line items from receipts using LLMs where they outperform traditional OCR); conversational expense (multi-agent assistants that help people create and complete expenses in natural language); missing-info assistants (agents that find required fields still empty and write back through existing expense APIs with safe partial updates and guardrails against prompt injection); admin and finance agents (assistants that can approve, reject, flag, route, and explain spend); quality, cost, and safety (evaluation harnesses, kill switches, careful handling of PII and payment-sensitive data).

What You'll Do

• Design and ship features in backend services (Java and Spring Boot) and/or web (TypeScript), with AI services in Python or TypeScript where that is the right fit.
• Own APIs and event-driven flows that move money, receipts, and policy decisions at company scale.
• Build or extend LLM-backed agents: tool use, grounding, streaming, session memory, retrieval, and evals.
• Improve document extraction and auto-itemization: quality, tax fields, latency, cost, and provider failover.
• Instrument production: observability, quality dashboards, chat satisfaction, extraction accuracy vs. human correction.
• Partner with Product and Design on employee, admin, and mobile AI surfaces.
• Review for correctness in financial systems: idempotency, auditability, permissions, no silent partial writes.
• Mentor others and write designs that teams across time zones can implement from.

What We're Looking For

• 5+ years building production software (8+ for Staff). Strong CS fundamentals.
• Depth in at least one of: Java/Spring Boot, modern TypeScript, or Python services.
• Experience with relational data modeling, APIs, and cloud (AWS). Messaging systems (Kafka or similar) are a plus.
• Shipped AI in a real product, not only notebooks: LLM APIs, tool/function calling, retrieval-augmented generation, evaluation, or document/vision extraction.
• Comfort with financial or workflow-heavy domains: expenses, payments, ERP, tax, or similarly high-stakes data.
• Clear written design, strong code review, and bias to production quality (tests, CI/CD, observability, incident ownership).
• Based in Berlin or London (or willing to relocate). Collaboration across US, Israel, and India time zones.

Nice to Have

Document OCR; VAT/GST or multi-currency; policy engines; agent frameworks; eval platforms; mobile AI UX.

Navan uses AI-assisted Automated Employment Decision Tool (Metaview) to assist with evaluating resumes against job qualifications for this role.