Founding Full-Stack Engineer

About the Role

We're a Y Combinator–backed EdTech startup on a mission to help people acquire languages and connect across cultures — and we're hiring a Founding Full-Stack Engineer to join our small, tight-knit founding team in San Francisco. This is a rare opportunity to shape the product, architecture, and engineering culture from the ground up at a fast-growing, mission-driven company in the language learning space.

You'll work in-person with the founders every day, own large swaths of the codebase, and ship features end-to-end — from backend services and data models all the way through mobile UI and deployment. If you thrive at the intersection of great craft, AI-driven product experiences, and genuine mission, this role is for you.

What You'll Do

• Collaborate in-person with the founding team daily in San Francisco.

• Own large parts of the codebase across mobile, web, backend, infrastructure, and AI.

• Ship full end-to-end product features — from backend logic through UI to deployment.

• Build high-performance mobile experiences in React Native.

• Implement and maintain video streaming and HLS pipelines.

• Develop AI-driven learning experiences using LLMs and audio/video models.

• Build and maintain backend services in Go.

• Design data models, schemas, and performance optimizations in PostgreSQL.

• Improve developer tooling, CI/CD pipelines, and observability.

• Influence foundational architecture, engineering culture, product direction, and UX.

• Move fast while maintaining a strong commitment to quality, craftsmanship, and reliability.

What We're Looking For

Must-haves (dealbreakers):

• 3+ years of professional software engineering experience delivering end-to-end features across mobile, web, and backend systems.

• Strong experience building backend services in Go (Golang) with PostgreSQL, including data modeling and performance optimization.

• Experience delivering mobile apps using React Native (Expo) or native iOS/Android development.

Required skills:

• Strong TypeScript fundamentals and solid foundations in HTML, CSS, JavaScript, and REST APIs.

• Deep understanding of at least two compiled languages, including Go and one other (e.g., Swift, Kotlin, C++, Java, C#).

• Writes testable code with unit, integration, and end-to-end tests (mocks, pure functions).

• Experience with at least one scripting language (Python or Ruby) for tooling and automation.

• Comfortable with Unix-based systems, Git, and terminal workflows.

• Excellent debugging skills using Chrome DevTools, RN profiler, or Xcode Instruments.

• Familiarity with video streaming (HLS) and building AI/LLM-driven features.

Nice to have:

• Cloud provider experience (AWS, GCP, Azure, or DigitalOcean).

• CI/CD experience with GitHub Actions.

• Profiling and performance optimization experience.

• Prior startup or founder experience.

• Comfortable using AI development tools (Cursor, Copilot, GPT, Claude, etc.).

• Speaks multiple languages or is actively learning one; familiarity with immersion-first language learning is a big plus.

Compensation & Benefits

• Salary: $150,000 – $200,000 USD annually

• Meaningful early-stage equity

• Visa sponsorship available when needed

Location

This role is fully on-site in San Francisco, CA. You'll work in person with the founding team every day. Candidates must be willing and able to commit to full-time, in-person work in San Francisco.