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Rethink recruit

Full-Stack Engineer

Rethink recruit, San Francisco, California, United States, 94199

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About HappyRobot HappyRobot is the AI-native operating system for the real economy-a system that closes the circuit between intelligence and action. By combining real-time truth, specialized AI workers, and an orchestrating intelligence, we help enterprises run complex, mission-critical operations with true autonomy. Our AI OS compounds knowledge, optimizes at every level, and evolves over time. We're starting with supply chain and industrial-scale operations, where resilience, speed, and continuous improvement matter most-freeing humans to focus on strategy and creativity. HappyRobot has raised $62M to date, including a $44M Series B in September 2025, from investors such as Y Combinator, Andreessen Horowitz (a16z), and Base10.

About the Role As a Full-Stack Engineer, you will own meaningful slices of our platform and infrastructure, shipping daily as we scale rapidly. You'll build end-to-end product surfaces in the web app and collaborate across the stack to optimize our voice-AI infrastructure for reliability, latency, and cost.

What You'll Do • Build entire sections of the product-front end and supporting services-with a focus on craft, performance, and usability • Ship high-quality React + TypeScript code and contribute to shared component libraries and design systems • Design and integrate APIs; collaborate on data models, caching, and observability to keep experiences fast and reliable • Assist with optimization of voice-AI infrastructure (throughput, latency, monitoring, cost controls) • Partner closely with design and product to iterate quickly from concept to production • Uphold code quality, testing, and CI/CD best practices while mentoring teammates through code reviews

Tech Profile • React and TypeScript (front-end strength required) • Strong generalist who can move across front end, APIs, and infrastructure touchpoints • Experience building production web apps and internal tooling • Comfort working in fast, product-led environments

Must Have • Excellent product sense and front-end design/style instincts • Strong communication skills; clear explanations of technical trade-offs • Passion for AI-driven products and platforms • Founder mindset: ownership, hard work, independence, and bias to ship

Why Join Us? • Opportunity to build at a high-growth AI startup backed by top investors • Fast growth trajectory with meaningful ownership and autonomy • Competitive compensation with equity • Comprehensive benefits (healthcare, dental, vision) • Work with a world-class team of engineers and builders

Our Operating Principles •

Extreme Ownership

- We take responsibility for outcomes and fix what's broken •

Craftsmanship

- We sweat the details; excellence is our default •

Be "Majo"

- Be genuine, kind, and collaborative; strong opinions, soft edges •

Urgency with Focus

- Move fast on the highest-leverage work •

Talent Density & Meritocracy

- A-players raise the bar and earn ownership •

First-Principles Thinking

- Rebuild from fundamentals; avoid copy-paste solutions