Staff Backend Engineer (Financial Ledger)

Location: Europe (Remote) Company: Voyagu Product: Radar The Mission Voyagu is a travel-tech company evolving Radar, our core platform, into a multi-agency SaaS system. The Financial Core is the spine of this transformation. We are looking for a Staff Backend Engineer to become the long-term technical owner of the system responsible for revenue calculations, payments, ledger-style events, and deterministic profit. The Context Active Evolution, Not a Blank Page This stream is already in motion. We started the Financial Core evolution a couple of months ago and have already defined the core architectural direction, introduced a ledger foundation, and implemented initial domain event flows. By the time you join, V1 will likely be in advanced implementation or early testing. Success in the first 3-6 months is not about inventing architecture from scratch, but about taking hands-on ownership of an actively evolving system, stabilizing V1, and identifying gaps to drive the direction toward V2. What You Will Work On Technical Ownership: Independently drive the direction of the Financial Core, challenge assumptions, and work closely with finance and engineering leadership. System Integrity: Validate the correctness of lifecycle flows and reconciliation behavior. Financial Logic: Handle ledger-style economic events, revenue/profit recognition, cost normalization, and client/supplier balances. Architecture: Improve the trustworthiness of the financial model and ensure strict financial invariants in a distributed, event-driven environment. Tech Stack Primary: Python (backend services), PostgreSQL (complex relational modeling). Cloud: AWS (Lambda, SQS, S3), AWS CDK (Infrastructure as Code). Focus: Data correctness and transactional consistency. What We Are Looking For: 8+ years of backend engineering experience, with significant time spent owning financial or transactional domain logic. Domain Depth: You have built real financial systems (payment platforms, billing infrastructure, ERP, or subscription platforms). Experience with "Live" Evolution: You know how to evolve complex production systems responsibly without breaking existing flows. Architecture & Hands-on: This is a hands-on ownership role, not a purely theoretical exercise. Mandatory Domain Requirements: We expect you to have deep, practical experience with: Ledgers and Reconciliation: Building systems that ensure deterministic correctness. Financial Operations: Reasoning about liabilities, revenue/profit recognition, and money flows. Complexity: Ability to describe and manage high-level financial domain complexity (e.g., multi-currency, complex tax logic, or multi-party settlements). Why This Role Matters The Financial Core determines our revenue correctness, scalability, and ability to successfully transition into a SaaS model. You will have direct architectural ownership of the foundation that powers all business operations.