Backend Software Engineer

Traveltechessentialist; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Healthcare coverage

Equity plans

Flexible time off

Parental leave

Commuting support

Job summary

Navan is seeking an experienced Expense Engineer to help own the end-to-end expense product across Berlin and London. You will ship backend and frontend features, build AI-backed agents, and improve extraction, policy, and audit capabilities at scale.

The role emphasizes production quality, observability, and cross-team collaboration across time zones. Ideal candidates have 5+ years in production software, strong CS fundamentals, and experience with Java/Spring Boot, TypeScript, or Python

Qualifications

• 5+ years building production software (8+ for Staff).
• Depth in Java/Spring Boot, TypeScript, or Python services.
• Experience with relational data modeling, APIs, and AWS.
• Shipped AI in a real product, including LLM APIs and retrieval.
• Comfort with financial or workflow-heavy domains.

Responsibilities

• Design and ship features in backend services (Java/Spring Boot) and/or web (TypeScript).
• Own APIs and event-driven flows at scale.
• Build or extend LLM-backed agents: tool use, grounding, streaming.
• Improve document extraction and auto-itemization.
• Instrument production with observability and dashboards.
• Collaborate with Product and Design on AI surfaces.
• Review for correctness in financial systems; mentor others.

Job description

Navan (Nasdaq: NAVN) is the AI-powered business travel, payments, and expense platform that makes it easy to book, pay, and close the books. Travelers get a product they actually want to use. Finance teams get real-time control, policy, and reconciliation. 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.

This is not a research-lab role and not a generic chatbot posting. You will ship in the same systems that already run receipt intelligence, conversational expense capture, missing-info assistants, and admin automation — then raise the bar on accuracy, latency, cost, and safety.

You may land on employee experience (web/mobile expense), international spend (itemization, per diem, mileage, tax receipts), admin and control (policy, custom fields, audit), or adjacent platform work (cards, statements, ERP). The product problems and the AI problems are shared.

What you'll work on:

The expense product, end to end

• Employee flows: transaction entry, drafts, receipts, trips, reimbursements, cards, and bank-linked spend
• International spend: line-itemization, per diem, mileage, VAT/GST, and tax receipts
• Admin and control: policy, approvals, custom and HR fields, audit logs, reporting
• Money movement and close: statements, purchase cards, reimbursements, accounting postings, and inbound company/user data

AI that is already in the product

• Receipt intelligence: extract merchant, amount, date, tax, and line items from receipts and documents at high daily volume. Improve quality, latency, and cost; compare and fail over between extraction providers, including large language models where they outperform traditional OCR.
• Conversational expense: multi-agent assistants that help people create and complete expenses in natural language (mileage, policy, personal context, knowledge retrieval). Streaming experiences on web and mobile, and the same command path in workplace chat tools.
• Missing-info assistants: agents that find required fields still empty (cost objects, GL, project, department, description), ground suggestions in the user's history and trips, stream progress, and write back through existing expense APIs — with safe partial updates, clear provenance, and guardrails against prompt injection and off-scope use.
• Admin and finance agents: assistants that can approve, reject, flag, route, and explain spend using tools over our APIs, search, and warehouse data — without bypassing permissions or audit.
• Quality, cost, and safety: evaluation harnesses for accuracy and latency; kill switches; careful handling of PII and payment-sensitive data on receipts and transactions. Prefer deterministic code for policy, catalogs, and tax rules; use models for language, ranking, and tool orchestration.

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 — not one-off prompt demos
• 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 (including unified travel-and-expense chat)
• 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. Willingness to cross the boundary.
• 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. You can talk about failure modes (hallucination, cost, latency, prompt injection, PII).
• 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.

Why this team, why these cities

Expense is where Navan's "AI-powered T&E" claim has to be true: receipts, chat, and admin agents sit on the same ledger as reimbursements and accounting close. Berlin and London put you next to EMEA customers who care about VAT, per diem, and audit — and next to a growing Expense engineering presence, not a satellite office doing overflow tickets.

Navan uses AI-assisted Automated Employment Decision Tool (Metaview) to assist with evaluating resumes against job qualifications for this role. All final decisions are made by human recruiters and hiring managers.

Human oversight:

Metaview does not automatically reject candidates or make final hiring decisions. Our recruiters and hiring managers review all outputs and make the final hiring decision regarding every application.

Your rights:

Your rights: If you prefer to have your application reviewed without AI assistance, you may request a human evaluation by entering your email here. Your decision to do so will not affect how your candidacy is evaluated.

Please refer to our Candidate Privacy Notice for more information about our processing of personal data, and your rights.

About Navan

Navan (Nasdaq: NAVN) is the global AI-powered business travel and expense platform that makes travel easy for frequent travelers. From finding flights and hotels, to automating expense reconciliation, with 24/7 support along the way, Navan delivers an intuitive experience travelers love and finance teams rely on. See how Navan customers benefit and learn more at navan.com.

Culture of Excellence

Our team is our competitive edge — a high-performance group of smart, driven people committed to winning together. This dedication to excellence is why we’ve been recognized as a Best Place to Work by Built In (2023–2026), a G2 Best Global Software Company (2025–2026), Forbes Cloud 100 (2022–2025), and CNBC Disruptor 50 (2022–2025). At Navan, we provide an environment where top talent excels, offering the autonomy and fast-paced trajectory needed to build a defining career and do the best work of your life.

Our Benefits

• healthcare coverage
• insurance offerings
• wellness resources for you and your family
• retirement savings programs
• opportunities to participate in our equity plans
• flexible time off
• country-specific holidays
• paid parental leave for all new parents
• connectivity and commuting support*
• mental health resources
• exclusive travel-related perks

Workplace Policy

Navan believes in the value of in-person connections, whether that’s sitting down to have lunch with one another, taking a walking 1:1, or collaborating in a room together. The connections forged through face-to-face interactions improve company culture and drive business results. Navan invests in global office spaces — in the U.S., Europe, and Asia, among others — that feel welcoming. In-office perks such as company-provided lunches and happy hours create a strong team environment to help you do your best work. Our employees work from the office four days a week. Please expect this policy for all roles that are tied to an office.

Equal Opportunity

Navan is an equal opportunity employer. We make all employment decisions based solely on merit. We provide equal employment opportunity to all applicants and employees without discrimination on the bases of race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics. We prohibit any such discrimination or harassment. This policy applies to all terms and conditions of employment, including hiring.

Accommodations

Navan complies with the Americans with Disabilities Act (ADA), as amended by the ADA Amendments Act, and all applicable state or local law. Navan will reasonably accommodate qualified individuals with a disability in connection with applications for employment as required by law.

If you need any assistance or accommodations due to a disability, you are welcome to email us at [e-mail].

Candidate Privacy Notice and Use of AI

As part of the recruitment process, certain personal data may be processed using automated tools, including tools that use AI. For details on how Navan collects and uses your personal data, please review Navan's Candidate Privacy Notice here.

Job Search Best Practices

We have been made aware of recruitment scams involving fraudulent attempts to lure job seekers into sending money or personal information in return for fake job offers or coerce them into purchasing equipment by electronic funds transfer (Zelle, Venmo, etc.) Legitimate Navan recruiters will never ask for money in any recruitment or onboarding activities. All available job openings at Navan will be posted on Navan’s website and all Navan recruiters will be reachable through an email address ending in “@navan.com” or “@navan.tech” or "@talent.navan.com".

*Applies to select locations.