Full-stack Engineer - Payments (Spain)

About CrossmintCrossmint is the leading enterprise-grade, all-in-one stablecoin and wallet infrastructure platform enabling fintechs and enterprises to integrate stablecoin rails and smart wallets with speed, compliance, and scale.Backed by Ribbit Capital, Franklin Templeton, NYCA, First Round, and Lightspeed Faction, with $23.6M raised in 2025. Trusted by more than 40,000 clients including global leaders such as MoneyGram, WireX, Toku, and more, Crossmint provides embedded smart wallets, on/offramps, cross-chain stablecoin orchestration, tokenization, and other blockchain primitives through simple, developer-friendly APIs that integrate in minutes and scale to millions of users.In January 2026, Crossmint secured MiCA authorization from Spain's CNMV, becoming one of a select few stablecoin infrastructure providers fully licensed to operate across all 27 EU member states and held to the same regulatory standards as traditional financial institutions. Crossmint also powers the Republic of the Marshall Islands' first digital UBI program, backs MoneyGram's new stablecoin cross-border experience launching in LATAM, and recently partnered with WireX to expand multichain stablecoin payment infrastructure to non-EVM networks like Stellar.The future of finance is stablecoin-native. Crossmint makes it easy to get there.LocationWe have offices in Madrid, and we are also open to a full remote setting from Spain.Type of employmentFull-time, indefinite contract.Seniority4+ years of experience.About the RoleThe 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, failure recovery in distributed financial flows.What You Will DoDesign 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 ForMust-haves4+ 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 plusHands-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.Please keep in mind:This is the full list of everything we’re looking for. You don’t need to check every single box to be a strong candidate, and having a good number of these would already indicate a solid fit for the role.Why Join Crossmint?The Payments team sits at the core of what Crossmint does. The infrastructure you build will be used by enterprises moving real money through stablecoin rails, in one of the first companies fully licensed under MiCA to operate across the EU. The team is small, the ownership is high, and the problems are genuinely hard. If you want to work on financial infrastructure that matters, without layers of process slowing you down, this is the role.BenefitsExtensive access to leading AI tools and subscriptions, with AI actively encouraged and integrated into daily workflows.Stock options program.We conduct two performance reviews annually. The first addresses performance ratings, bonuses, and promotions. The second encompasses these elements along with salary adjustments reflecting inflation and market conditions.Unlimited Paid Time Off.Parental Leave program.Company laptop + Annual home office and productivity stipend.Daily stipend for in-office meals and/or commuting to the office.Three company-paid off-sites each year. R