Web3 Solana Jobs in Spain

About MoonPayHi, we’re MoonPay. We’re here to onboard the world to the decentralized economy by making digital money move as universally and effortlessly as the internet.Why?Because crypto, stablecoins and blockchain aren’t just technologies. They’re tools for global financial empowerment. They give people and businesses more control over their money, their digital assets, and their future, opening access to legacy financial systems that have been out of reach for many.What we doMoonPay is a unified payments platform for digital currency. We make it easy for anyone, anywhere, to buy, sell, swap and pay in digital currencies as easy as sending an email. That simplicity is intentional, our focus is reducing complexity so people can participate confidently, without needing to be crypto experts. We power the entire flow between fiat and crypto end to end, with compliance, identity checks, fraud prevention, and settlement all built in. This end-to-end approach reflects how we work internally: with accountability, rigor, and trust built into everything we ship.Proven at scaleTrusted by over 30 million customers and over 500 ecosystem partners, our secure, enterprise-grade platform is driving mainstream crypto adoption worldwide. Behind those numbers are millions of real people and organizations relying on MoonPay every day. We collaborate with innovative brands and projects to build secure, scalable solutions for a blockchain-powered future. This is an opportunity to help shape systems, not just scale them. And we’re committed to doing it right. Fully licensed in the U.S. and regulated across the UK, EU, Canada, and Australia, because trust and compliance are non-negotiable. But we’re just getting started. We’ve launched a consumer app that makes crypto accessible, intuitive, and usable for everyone, and it’s growing fast. We’re iterating every day to make it the best it can be. If you believe financial freedom should be for everyone. If you believe in building a fairer, more open financial system - we want you with us. To build systems that benefit all, we need contributions from all, regardless of background. Come build the future of payments and the decentralized economy with MoonPay. Let’s make financial freedom and autonomy the new normal.About the OpportunityOur Engineering team builds the technology that empowers MoonPay to innovate rapidly and scaleefficiently. We thrive in small, collaborative cross-functional teams of 4-6 engineers, working closely witha dedicated Product Manager and Product Data Analyst. MoonPay is seeking individuals with experiencein developing blockchain applications and integrations to contribute to our expanding consumer and B2Binitiatives. Our focus areas include self-custody wallets, DeFi Trading, on-chain asset delivery, andinnovating on what the future of Web3 means.

What You Will Do

• Transaction Infrastructure at Scale:
• Design and improve high-volume transaction broadcasting pipelines
• Manage transaction lifecycle
• Detect, retry, rebroadcast, and safely recover stuck transactions
• Wallet & Lifecycle Management
• Contribute to wallet infrastructure and automation systems
• Implement safe parallel transaction handling
• Improve monitoring, observability, and operational guardrails
• Design systems with financial correctness, reconciliation and auditability in mind
• Cross-Chain & DeFi Integrations:
• Build infrastructure supporting cross-chain and multi-step flows (fiat to on-chain and vice versa)
• Handle non-atomic multi-step journeys across chains
• Design state machines and recovery strategies for partial failure scenarios
• Support routing mechanics and swap execution considerations, such as price impact, liquidity changes, including MEV awareness
• Build reliable off-chain services that interact with on-chain contracts
• End-to-End Engineering Ownership:
• Participate in estimation, planning, and execution of projects, features, and integrations
• Develop and maintain thoroughly tested, high-quality, and performant code
• Collaborate closely with Product Managers to design scalable implementation strategies
• Contribute to reliable, maintainable systems that evolve with product needs
• Participate in incident response and post-mortems
• Improve reliability, alerting, and system resilience
• Continuously evolve infrastructure to support growing volume and complexity

About You

• Must-Have
• Strong backend/platform engineering fundamentals
• Experience operating production systems with real uptime requirements
• Hands-on experience interacting with live blockchain networks in production
• Clear understanding of transaction lifecycle in at least 1 Blockchain and failure recovery
• You think in failure modes, not just happy paths
• Strong Signals
• You can explain a real production incident end-to-end
• Experience with at least 1 wallet infrastructure (Eth, Bitcoin, Solana) or custody systems
• Awareness of MEV, slippages, pricing impact and swap execution risks
• Experience with high-throughput or financial systems
• Bonus points
• Experience working at exchanges, custody providers, wallet infrastructure teams, or high-volume DeFi platforms
• Familiarity with UTXO-based chains (e.g., Bitcoin), including coin selection and fee bumping strategies (RBF / CPFP)
• Experience designing cross-chain or multi-step transaction orchestration systems
• Familiarity with blockchain indexing or event ingestion pipelines
• Understanding of common token standards (ERC-20, SPL) and interacting with smart contracts from backend services

BLOCK Values We’re looking for people who live our core values, those who strive for excellence and want to leave a lasting legacy on the global financial system. Our values:B - Be HungryL - Level UpO - Own ItC - Crypto CuriousK - KaizenResearch has shown that women are less likely than men to apply for this role if they do not have experience in 100% of these areas. Please know that this list is indicative, and that we would still love to hear from you even if you feel that you are only a 75% match. Skills can be learnt, diversity cannot.Benefits & Perks 💡💰Competitive salary package 🤝 Equity package: We believe financial freedom starts with our employees, so all employees have ownership at MoonPay📈 Pay for performance equity bonus: Those who drive outsized outcomes receive outsized rewards 🚀 Moonshot award. We honor exceptional impact - 10 employees twice a year, each earning a $250,000 equity grant.🏝 Unlimited holidays: We give you the autonomy to choose when to work (and when to switch off)🌍 Hybrid working schedule: Work fully remotely or your nearest Moonbase, the choice is yours 🩺 Private Healthcare benefits: To protect you and your loved ones 🍼 Enhanced parental leave: So you can spend more time with your loved ones without a second thought📚 Annual training budget: We support your training journey every step of the way 🪑 Home office setup allowance: Create the home office of your dreams 👛 Remote working allowance: Those working fully remotely get a little extra for utilities 💰 Monthly budget to spend on our products and zero fee crypto transactions: Cultivate your inner DEGEN 💰 Employee referral programme: Great people know great people, refer them to receive 10K in USDC ✈️ Regular remote company offsites: Meet your colleagues regularly for high impact in person sessions and hackathons 🚀 Working in a disruptive and fast-growing company where excellence is rewarded Commitment To DiversityAt MoonPay we believe that every voice matters. We strive to create a mindful and respectful environment where everyone can bring their authentic self to work, and experience a culture that is free of harassment, racism, and discrimination. That’s why we are committed to diversity and inclusion in the workplace and are a proud equal opportunity employer. We prohibit discrimination and harassment of any kind based on race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, protected veteran status or any other characteristic protected by law. This policy applies to all employment practices within our organization, including, but not limited to, hiring, recruiting, promotion, termination, layoff, and leave of absence. MoonPay is also committed to providing reasonable accommodations in our job application procedures for qualified individuals with disabilities. Please inform our Talent Team if you need any assistance completing any forms or to otherwise participate in the application process.We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.