Senior/Staff Software Engineer, Developer Platform

The role

Build and own MoonPay's developer platform: APIs, SDKs and embedded components that let partner developers add native payment and crypto experiences to their own products. The role covers browser and mobile integration, payment-critical reliability, and making the platform easy for developers to adopt and debug.

What you will do

• Design and build APIs, SDKs and embedded components used by external developers.
• Turn existing authentication, identity, payment and purchasing capabilities into reusable platform modules.
• Develop secure browser and mobile integration patterns across iframes, web views and native apps.
• Create stable abstractions over complex payments, compliance and crypto infrastructure.
• Build reference applications, sandboxes and tooling that help developers move from exploration to production.
• Own the full developer journey, from obtaining credentials to completing a live transaction.
• Design clear interfaces for sessions, authentication, quotes, payment methods, transaction state and errors.
• Make APIs and SDKs hard to misuse and easy to debug, with clear versioning and migration strategies.
• Build payment systems that handle retries, duplicate events, delayed responses and failing dependencies.
• Measure API and SDK adoption, integration success, reliability and developer experience.

Required qualifications

• Experience building APIs, SDKs, embedded components or integration tooling used by third-party developers.
• Understanding of browser and mobile behaviour, including sessions, storage, cross-origin communication and embedded experiences.
• Strong JavaScript and TypeScript fundamentals and production client-side or SDK experience.
• Understanding of API and SDK design: versioning, backwards compatibility, documentation, error design and safe migrations.
• Experience building distributed systems that handle events arriving twice, late or out of order.
• Product judgement to turn complex platform capabilities into interfaces developers can adopt.
• Ownership of developer-facing software from design through launch, adoption and production support.

Nice to have

• Payment APIs, checkout SDKs, embedded financial products or payment-method integrations.
• Products similar to Stripe Elements, Stripe.js, Plaid Link or Braintree client SDKs.
• Secure iframes, web views, postMessage or cross-origin browser infrastructure.
• SDKs across web, iOS or Android.
• Sandboxes, test environments, reference applications or developer documentation.
• Webhooks, idempotency, transaction state machines and payment orchestration.
• Authentication, identity or KYC integrations.
• Familiarity with cryptocurrency, wallets or digital-asset products.
• Familiarity with TypeScript, Node.js, React, GCP, PostgreSQL, Redis and Kubernetes.

Benefits

• Competitive salary package.
• Equity package, with all employees having ownership.
• Pay-for-performance equity bonus.
• Moonshot award: 20 employees a year each earn a $250,000 equity grant.
• Pension with employer contributions from day one.
• Employee referral program: 10K in USDC per referral.
• Flexible time off and an end-of-year company-wide recharge period.
• Birthday leave and enhanced parental leave.
• Hybrid schedule: fully remote or from the nearest Moonbase.
• Private healthcare benefits.
• Wellhub wellness membership.
• Enterprise access to the latest AI tools.

Before you apply

• Hiring includes research-based guidance that candidates need not match every listed area; the posting says it would still like to hear from candidates who meet about 75% of the list.

About the company

MoonPay is building the operating system for value movement, covering crypto, stablecoins and tokenized assets across fund, tokenize, trade and spend offerings. It reports 30M+ customers and 500+ ecosystem partners, is licensed in the U.S. and regulated across the UK, EU, Canada and Australia.