Senior Full-stack Engineer

ABOUT US

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

This is an extraordinary moment to join us. We're in the middle of a fundamental agentic shift in software development, and are embracing the change https://www.speak.com/blog/agentic-engineering. We're operating in an agentic-first world, where the role of a builder is shifting from writing every line of code to designing systems that build, test, and improve themselves.

At Speak, you'll use AI agents as core collaborators in your day-to-day workflow—helping you move faster, explore more ideas, and focus on the highest-impact problems. That means embracing ambiguity, iterating quickly, and working fluidly across functions—not just within a single discipline.

We're looking for a Full-stack Engineer who is excited to rethink how work gets done in an AI-native environment, and who want to help define what building looks like in this new paradigm.

This role spans the entire stack — while initial projects may lean frontend, expect to pivot into backend work as well, contributing to novel AI-powered product experiences. The ideal candidate will have experience working in close coordination with product, design, and machine learning teams, as well as have a background in building polished consumer applications. This role sits at the center of developing our newest products focused on programmatic, conversationally-driven language learning and will be an instrumental contributor to the future of our company.

WHAT YOU'LL BE DOING

• Building novel AI-driven product experiences and user interfaces on the web

• Owning the entire development cycle of features, from conception to production

• You'll be able to write code very quickly, ship frequently, and make a huge impact on our business by helping us scale our content

WHAT WE'RE LOOKING FOR

• 4+ years of experience building highly polished web-based product experiences, including extensive experience with React

• Experience using coding agents (e.g. Claude Code, Codex, Cursor) as core collaborators in your day-to-day workflow — not just as autocomplete, but as active partners in designing, testing, and shipping.

• You appreciate balancing doing things the "right way" but also can build things scrappily if necessary

• You enjoy shipping things quickly and frequently

• You're an excellent communicator and enjoy collaborating with people across all functions

• We welcome applicants across all levels of engineering, including mid, senior, and staff.

OFFICE

• San Francisco, CA

WHY WORK AT SPEAK

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.