Senior Software Engineer, Developer Platform

About the Opportunity

MoonPay is building a developer platform that allows partners to create native payment and crypto experiences directly inside their own products.

Historically, partners integrated MoonPay through a hosted widget and redirected users into a fixed MoonPay journey. We are now breaking the underlying system into reusable modules covering authentication, identity, KYC, quotes, payment methods and purchasing.

These capabilities are exposed through APIs, SDKs, embedded components, iframes and web views. Our goal is for a partner developer to integrate MoonPay’s full capabilities without needing ongoing implementation support from our team.

This role owns the developer-facing layer between MoonPay’s underlying payments infrastructure and the products our partners build. You will work across browsers, mobile applications and backend APIs to make complex financial workflows feel simple, predictable and native.

As a Senior Software Engineer, you will hold a hands-on technical position. You will build the platform itself rather than implementing one-off integrations for individual customers.

Must-have experience and skills

• External developer products. You have built APIs, SDKs, embedded components or integration tooling used by third-party developers.

• Browser or mobile depth. You understand how browsers and mobile applications behave beneath the framework level, including sessions, storage, cross-origin communication and embedded experiences.

• JavaScript and TypeScript. You have strong language fundamentals and have built production client-side or SDK infrastructure.

• API and SDK design. You understand versioning, backwards compatibility, documentation, error design and safe migrations.

• Distributed systems. You build correctly when events arrive twice, late or out of order and when dependencies fail.

• Product judgement. You can turn complex platform capabilities into interfaces that developers can understand and adopt.

• Ownership. You have taken developer-facing software from design through launch, adoption and ongoing production support.

Nice-to-have experience

• Built payment APIs, checkout SDKs, embedded financial products or payment-method integrations.

• Built products similar to Stripe Elements, Stripe.js, Plaid Link or Braintree’s client SDKs.

• Experience with secure iframes, web views, postMessage or cross-origin browser infrastructure.

• Developed SDKs across web, iOS or Android.

• Built sandboxes, test environments, reference applications or developer documentation.

• Experience with webhooks, idempotency, transaction state machines and payment orchestration.

• Worked on authentication, identity or KYC integrations.

• Familiarity with cryptocurrency, wallets or digital-asset products.

• Familiarity with our stack: TypeScript, Node.js, React, GCP, PostgreSQL, Redis and Kubernetes.

Benefits & Perks 💡

• 💰 Competitive salary package

• 🤝 Equity package: 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. 20 employees a year, each earning a $250,000 equity grant

• 📊Pension: employer contributions from day one

• 🎁Employee referral program: refer great people, earn 10K in USDC

• 🏝 Flexible Time Off: choose when to work and when to switch off

• 🔋Recharge Period: end-of-year company-wide time off to rest and reset

• 🎂 Birthday leave: take the day off to celebrate you

• 🍼 Enhanced parental leave: more time with family, no second thought

• 🌍 Hybrid working schedule: work fully remotely or from your nearest Moonbase

• 🚆 Commuter benefits: public transport to and from the office

• 🩺 Private healthcare benefits: to protect you and your loved ones

• 🧘 Wellhub wellness membership: access to gyms, studios, classes, and wellness apps in one membership

• 🤖 Enterprise access to the latest AI tools: Claude, ChatGPT, Gemini and whatever's next

• 🍱 Lunch credit: meals covered on the days you're in the office

• 🪑 Home office setup allowance: build the home office of your dreams

• 👛 Remote working allowance: those working fully remotely get a little extra for utilities

• 🌕 Monthly product budget and zero-fee crypto transactions

• 📚 $1,000 Annual training budget: we support your learning journey

• 🎯 High Potential Program: structured development, mentorship, and stretch opportunities

• ✈️ Regular remote company offsites: high-impact in-person sessions and hackathons

• 🚲 (Ireland) Cycle to Work scheme: tax-efficient bike, gear, and safety kit

• 🔌 (UK) EV Salary Sacrifice: lease an electric vehicle through pre-tax salary