Backend Engineer, Payments

Learning a language can change a life by opening doors to new cultures, careers, and communities. Two billion people around the world are actively trying to learn a language, but the best way to learn (one-on-one tutoring) is hard to access at scale and hasn’t been meaningfully improved in decades. Speak is building a human-level, AI-powered tutor in your pocket: a conversation-first experience that lets learners actually speak, get instant feedback, and progress through carefully designed lessons. The result is a complete path from beginner to confident speaker across multiple languages.

Speak first launched in South Korea in 2019, where Speak has now become the number one language learning app, and we now serve learners across many markets and 15+ languages. Speak is one of the world’s leading AI companies, with over $150m raised in venture investment from OpenAI, Accel, Founders Fund, Khosla Ventures, and more, with a distributed team across San Francisco, Seoul, Tokyo, Taipei, and Ljubljana.

We’re hiring our first dedicated payments engineer to own the reliability of payments at Speak. Every Speak payment is a subscription, and that revenue runs through Paddle, RevenueCat (the App Store and Google Play) and Stripe, with new providers on the way. Until now, payments work has been shared across teams without a single owner. You’ll be that owner: the point of contact and directly responsible engineer for how Speak bills, renews, and grants access to millions of learners.

You’ll start embedded with one of our growth teams, which also owns monetization, and over time anchor payments within our platform organization. As the first engineer in this area, you’ll set the architecture, standards, and roadmap for payments at Speak, with a high degree of autonomy and a direct line to revenue.

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  Owning the reliability of Speak’s subscription payments end to end, from purchase and renewal through cancellation, refunds, and entitlements

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  Building and maintaining our integrations with Paddle, RevenueCat, and Stripe in Node.js, and leading the rollout of new payment providers

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  Designing for correctness: idempotent webhook handling, reconciliation across providers, and safe retries

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  Putting monitoring, alerting, and runbooks in place so payment issues are caught before learners or finance notice them

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  Leading incident response and postmortems for payments, and fixing root causes

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  Setting the standards for how other teams change payments code, and reviewing changes that touch billing

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  Partnering with growth, product, finance, and support on pricing, paywall experiments, and revenue reporting

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  Mentoring engineers and raising the reliability bar across our backend

• 10+ years of software engineering experience, including staff-level ownership of production systems

• Deep experience building and operating recurring subscription billing for a consumer product

• Hands-on experience with App Store or Google Play billing (directly or through RevenueCat), Stripe Billing, or Paddle

• Strong backend fundamentals in Node.js and TypeScript or a comparable language, with solid relational database skills

• A track record of making payment systems more reliable: fewer incidents, cleaner reconciliation, safer migrations

• Comfort defining your own roadmap in an area that doesn’t have one yet

• Clear communication with engineering, product, and finance partners

• Contributing to an AI-native development workflow — reviewing plans and designs before implementation, creating strong verification loops, and shipping safely with AI-assisted tooling

• Excited about working in person in San Francisco at least 3 days per week

• Migrating between payment providers or consolidating several into one system

• International payments, taxes, and currencies, especially across APAC markets

• Worked on an app used by 1M+ users

• Built entitlement systems shared across mobile and web