Full-Stack Engineer - Enterprise

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 looking for a senior full-stack engineer to serve as a hands-on technical contributor for Speak for Business, the pod building the enterprise layer of Speak. You’ll work across the B2B product surface — partner portals, reporting, B2B subscription mechanics, admin experiences, and learner features that require an enterprise touch. You’ll work primarily in TypeScript across Node.js and Postgres, partnering with engineers in adjacent pods where experiences cross team boundaries.

You’ll turn product requirements and business goals into clear technical designs, contribute hands-on across the stack, and help set a high bar for architecture, reliability, and code quality on a small, fast-moving team. Near-term work includes B2B onboarding flows, partner-facing reporting, subscription and billing mechanics, and enterprise-ready features that support our growing Sales and CS motion.

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  Building and owning full-stack features across the Speak for Business product surface, including partner portals, admin dashboards, reporting, and B2B subscription workflows

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  Designing and implementing backend services, APIs, and data models that support multi-tenant enterprise use cases

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  Leading cross-functional integrations across authentication, entitlements, billing, CRM, and analytics

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  Partnering closely with product, design, sales, and customer success to define scope and deliver end-to-end outcomes

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  Setting a high quality bar for privacy, security, observability, data integrity, and safe rollouts

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

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  Mentoring engineers and raising the team’s bar for technical judgment and ownership

• 6+ years of experience building production-scale web applications, with strong proficiency in TypeScript, Node.js, and SQL databases (Postgres preferred)

• Full-stack capability — comfortable across both frontend and backend, with solid database fundamentals

• Experience with or strong interest in B2B SaaS, enterprise product surfaces, or multi-tenant systems

• Strong product and business judgment, with the ability to translate enterprise requirements into pragmatic scope and durable technical foundations

• Experience designing APIs and backend services, reasoning clearly about system boundaries, and working with relational data

• Ability to work autonomously and adapt quickly on a small team with low meeting overhead and high ownership expectations

• Excellent cross-functional communication and a collaborative working style

• Excitement about AI-assisted development, paired with thoughtful verification and a high production-quality bar

• Nice to have:

  • Experience with multi-tenant B2B SaaS, SSO/SAML, billing, invoicing, or entitlements

  • Familiarity with admin dashboards, reporting, or analytics integrations

  • Experience with B2B account models, roles, or provisioning

  • CRM or marketing technology integrations

  • Experience building for both consumer and B2B surfaces