Founding Full-Stack Engineer

About the Role

A Y Combinator–backed EdTech startup in San Francisco is hiring a Founding Full-Stack Engineer to join its founding team. The company is building an immersive, short-form video language-learning platform — backed by science and already trusted by hundreds of thousands of learners — that helps people achieve real conversational fluency.

This is an in-person, early-stage role with meaningful equity. You'll work side-by-side with the founders every day, own large portions of the codebase, and have a direct hand in shaping product direction, engineering culture, and architecture from the ground up. The stack spans mobile, web, backend, infrastructure, and AI.

What You'll Do

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

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

• Ship complete end-to-end product features — from backend logic through UI to production 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 without sacrificing quality, craftsmanship, or reliability.

What We're Looking For

Dealbreakers (must-haves):

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

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

• Proven 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 knowledge of at least two compiled languages — Go plus one of Swift, Kotlin, C++, Java, or 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.

• Strong 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 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 a spoken language; familiarity with immersion-first language learning is a plus.

Compensation & Benefits

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

• Equity: Meaningful founding-team equity package

• Visa sponsorship: Available when needed

Location

This role is fully on-site in San Francisco, CA . Candidates must be willing and able to work in person full-time. Visa sponsorship is available.