Senior Backend Engineer - Payments & Fintech

Accountabilities: Design and implement a canonical billing and entitlement ledger using an append-only, journals-as-truth architecture and PostgreSQL, ensuring every entitlement can be traced to a valid paid order. Own the complete subscription lifecycle, including purchases, renewals, resubscriptions, upgrades, downgrades, plan changes, trials, cancellations, lapses, proration, and dunning across multiple payment gateways. Build reliable payment gateway ingestion pipelines with idempotent and replay-safe webhook processing, normalization, dead-letter handling, and daily reconciliation between gateway records and internal books. Implement robust handling of refunds, chargebacks, disputes, credits, and partial or zero-value settlements while preventing double counting and ensuring accurate allocation of payment amounts. Create trustworthy financial and entitlement data pipelines supporting accounting close, revenue recognition, indirect tax requirements, exchange reporting, and conversion and retention analytics. Own the customer-facing billing experience, including checkout and account management functionality, ensuring the frontend experience remains fully aligned with the underlying financial ledger. Lead the migration of the live business from legacy account and billing models, including historical data backfills, parallel operation, reconciliation, validation, and controlled regional cutovers. Establish engineering practices that prioritize financial correctness, auditability, observability, reliability, and safe operation under concurrency and scale. Requirements 6–10 years of backend engineering experience, with deep expertise in Go and strong relational database design and SQL skills. Proven experience building or rebuilding payment, subscription, billing, and ledger systems end-to-end, including gateway integrations, idempotent webhooks, renewals, upgrades, proration, cancellation, dunning, refunds, and disputes. Strong understanding of financial systems surrounding payment ledgers, including reconciliation, revenue recognition, taxation, financial reporting, and append-only or event-sourced ledger architectures. Experience designing systems where derived state is based on authoritative financial records and where transactions must remain accurate and auditable under concurrency. Background working on B2B products involving complex billing, metering, plans, add-ons, multi-tenant environments, or partner billing. Advanced SQL skills and the ability to independently investigate financial discrepancies and trace issues directly through underlying data. Working knowledge of TypeScript, React, and modern frontend development, with the ability to build and maintain customer-facing billing and checkout experiences. Experience with multi-entity, multi-currency, or international billing is highly valuable, including familiarity with EU VAT/OSS, GST/IGST, or comparable tax frameworks. Experience with AWS Cognito, identity systems at scale, legacy data migrations, financial reconciliation, finance-close workflows, or trusted revenue-reporting pipelines is a plus. Fintech or trading-industry experience is advantageous but not essential; strong payments and billing expertise is the priority. Strong ownership, analytical thinking, attention to detail, and communication skills, with the ability to collaborate closely with finance, operations, and technical leadership. Comfortable working in a fast-paced environment where financial correctness and system reliability have a direct impact on the business. Benefits Full-time employment. Remote opportunity for Europe-based candidates. Minimal travel requirements. Opportunity to take ownership of a business-critical financial platform. Direct collaboration with senior technical, finance, and operations stakeholders. Significant impact on payment reliability, revenue integrity, customer entitlements, and financial reporting. Opportunity to work on complex payment, subscription, ledger, and migration challenges at international scale. ASAP start date.