Senior Software Engineer, Expense

Responsibilities

• Design and ship features in backend services using Java and Spring Boot, web applications using TypeScript, and AI services using Python or TypeScript.
• Own APIs and event-driven flows for money, receipts, and policy decisions at company scale.
• Build and extend LLM-backed agents with tool use, grounding, streaming, session memory, retrieval, and evaluations.
• Improve document extraction and automatic itemization, including quality, tax fields, latency, cost, and provider failover.
• Instrument production with observability, quality dashboards, chat satisfaction metrics, and extraction accuracy tracking.
• Partner with Product and Design on employee, administrator, and mobile AI experiences.
• Ensure correctness in financial systems through idempotency, auditability, permissions, and prevention of silent partial writes.
• Mentor engineers and write technical designs for distributed teams.

Requirements

• 5+ years building production software; 8+ years for Staff-level roles.
• Strong computer science fundamentals.
• Depth in at least one of Java/Spring Boot, modern TypeScript, or Python services, with willingness to work across technologies.
• Experience with relational data modeling, APIs, and cloud platforms such as AWS.
• Experience shipping AI in a production product, including LLM APIs, tool or function calling, retrieval-augmented generation, evaluation, or document/vision extraction.
• Ability to discuss AI failure modes such as hallucination, cost, latency, prompt injection, and PII handling.
• Comfort with financial or workflow-heavy domains such as expenses, payments, ERP, or tax.
• Strong written design and code review skills, with a focus on tests, CI/CD, observability, and incident ownership.
• Based in or willing to relocate to Berlin or London.

Nice to Have

• Kafka or similar messaging systems.
• Document OCR.
• VAT/GST or multi-currency experience.
• Policy engines.
• Agent frameworks.
• Evaluation platforms.
• Mobile AI user experience.

Benefits

• Opportunity to work on expense, payments, accounting, and AI products used by companies worldwide.