Backend Engineer, Payments

Our mission is to reinvent the way people learn, starting with language.

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.

About this role

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.

What you'll be doing

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

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

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

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

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

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

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

• Mentoring engineers and raising the reliability bar across our backend

What we're looking for

• 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

Nice to haves

• 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

1. Join a fantastic, tight-knit team at the right time: we're growing very quickly, we've most recently raised our Series C from some of the top investors in the valley, and we've achieved product-market fit in our initial markets. You'd join at a magical time when a single person could significantly change the course of the company.

2. Do your life's work with people you’ll love working with: we care strongly about our craft and want every person at Speak to feel like they're growing every day. We believe in the idea that working with people you both enjoy and have respect for makes everything better. We hire thoughtfully and only work with people we admire deeply.

3. Global in nature: We're live in over 40 countries and launching in a number of new markets soon. We have dedicated offices in San Francisco, Ljubljana, Seoul, Tokyo, and Taipei, and you’ll have the opportunity to talk to users in each of these regions on a regular basis as well as travel.

4. Impact people's lives in a major way: Learning a language is one of the single most life-changing skills one can learn, and right now 99% of people never achieve their goal because the process is broken. We’re helping millions of people achieve their goals and improve their lives.

Speak does not discriminate based upon race, religion, color, national origin, gender (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, gender expression, age, status as a protected veteran, status as an individual with a disability, or other applicable legally protected characteristics.