Full-stack Engineer - Payments (Spain)

Full-stack Engineer – Payments (Spain) About the Role The Payments team owns the infrastructure that moves real money through Crossmint, including on/offramps, cross‑chain stablecoin flows, and the payment rails that clients like MoneyGram and WireX build on top of. This is not a billing or internal tooling role. You will be working on systems where correctness, uptime, and consistency actually matter, across multiple providers, chains, and fiat currencies. The challenges are real: multi‑provider routing, idempotency at scale, reconciliation across async settlement windows, and failure recovery in distributed financial flows. What You Will Do Design and build payment infrastructure: processor integrations, transaction pipelines, settlement and reconciliation workflows, and the APIs clients depend on. Own critical financial flows end to end, including failure modes, retry logic, state management, and edge cases that matter in production. Work across the stack: backend‑heavy, but you will contribute to APIs, dashboards, and the interfaces clients use to interact with payment systems. Ensure data integrity across providers and chains: balances, transaction states, and audit trails that stay consistent even when third‑party systems don’t. Contribute to architecture decisions: write design docs, review peers’ proposals, and help the team make good long‑term calls. Participate in on‑call rotations (paid, once or twice per quarter) and own incidents on the systems you build. Help onboard and mentor newer engineers as the team grows. What We Are Looking For Must‑haves 4+ years building and maintaining production backend systems, ideally involving financial data, payments, or transaction‑critical infrastructure. Strong proficiency in TypeScript or JavaScript (our primary stack), or another typed modern language with willingness to move quickly. Solid understanding of distributed systems fundamentals: idempotency, consistency guarantees, failure handling, async workflows. Fluent in English, written and spoken. Strong plus Hands‑on integration experience with Stripe, Adyen, or similar payment processors. Exposure to stablecoin infrastructure, crypto payments, wallets, or cross‑chain systems. Experience operating financial systems in regulated environments. Location Madrid office or full remote from Spain. Type of Employment Full‑time, indefinite contract. Seniority 4+ years of experience. Benefits Extensive access to leading AI tools and subscriptions. Stock options program. Two performance reviews annually. Unlimited paid time off. Parental leave program. Company laptop + annual home‑office stipend. Daily stipend for in‑office meals and/or commuting. Three company‑paid off‑sites each year. Health and dental insurance fully covered. Flexible retribution with tax benefits through Cobee. Crossmint is an equal‑opportunity employer committed to diversity and inclusion. #J-18808-Ljbffr