Software Engineer, Product

Mosaic.tech; San Francisco (CA); On-site; USD 300,000 - 475,000; Full time

Job summary

Thinking Machines, based in San Francisco, is hiring a Full Stack Engineer to conceive, build, and ship AI-powered products from the ground up.

You’ll be the first engineer on new ideas, owning technical direction and product outcomes while partnering with researchers, designers, and product teams. This role emphasizes rapid prototyping and end-to-end ownership, delivering value to real users in weeks rather than quarters.

Qualifications

• 5+ years of professional software engineering experience.
• Ownership across frontend and backend systems.
• Proven track record shipping production web applications end-to-end.
• Comfort in ambiguous, fast-changing environments.
• Experience making pragmatic technical tradeoffs to move quickly without accumulating risk.

Responsibilities

• Design, build, and ship full-stack features across web apps (backend to frontend).
• Prototype rapidly using model capabilities to create usable product experiences.
• Move ideas from concept to live surface for real users, iterating on feedback.
• Collaborate with researchers to translate model behavior into product decisions.
• Partner with design and product to define what to build, not just how.
• Own the architecture, focusing on scalability, reliability, and maintainability.
• Help define engineering practices and coding standards for the team.

Skills

Full-stack engineering

Frontend & Backend

Production web apps

Ambiguity navigation

Tradeoff decisions

Research collaboration

LLM-based products

Job description

About Thinking Machines

The mission of Thinking Machines is to build AI that extends human will and judgment. We are training frontier models with Inkling, developing Tinker to let people make models their own, and crafting interfaces that broaden human-AI communication. We believe the future worth building is human, and we're hiring people who want to build it.

About the Role

We're hiring a Full Stack Engineer to help conceive, build, and ship new AI-powered products from the ground up. You'll work on early-stage product ideas that sit at the edge of what our models can do — moving from prototype to something real people rely on, often within weeks rather than quarters.

This role sits at the intersection of product, design, and research. You'll partner closely with researchers to translate emerging model capabilities into interfaces and experiences, and with product and design to figure out what's worth building next. You'll frequently be the first engineer on a given idea, which means real ownership over both the technical direction and the product itself.

We're looking for someone who is energized by ambiguity, comfortable working across the entire stack, and motivated by getting new things in front of real users quickly.

What You'll Do

• Design, build, and ship full stack features across our web applications — from backend services and APIs to production-quality frontend interfaces.

• Prototype rapidly with new and emerging model capabilities, turning early research results into usable product experiences.

• Take new product ideas from a rough concept to a live surface that real users can try, iterating quickly based on feedback.

• Partner with researchers to understand model behavior, constraints, and capabilities, and translate them into product decisions.

• Work with design and product partners to define what to build, not just how to build it.

• Own the technical architecture of the products you build, including decisions about scalability, reliability, and maintainability as they mature.

• Help set engineering practices and technical standards for a growing product engineering team.

Skills & Qualifications

Minimum Qualifications

• 5+ years of professional software engineering experience, with demonstrated ownership across both frontend and backend systems.

• Strong track record shipping production web applications end to end, from data model and API design through polished user-facing interfaces.

• Comfort working in ambiguous, fast-changing environments where product direction is still being discovered.

• Experience making pragmatic technical tradeoffs to move quickly without accumulating unmanageable risk.

Preferred Qualifications

• Experience building products on top of large language models or other frontier AI systems, including working around their quirks and limitations.

• A strong product sense — you enjoy figuring out what's worth building as much as how to build it.

• Experience as an early or founding engineer at a startup, or leading a product from 0 to 1.

• Familiarity with modern frontend frameworks and a good eye for interface design and usability.

• Experience with distributed systems, infrastructure, or backend performance work at scale.

• A history of working closely and effectively with researchers, designers, or other non-engineering partners.

Logistics

• Location: This role is based in San Francisco, California.

• Compensation: Depending on background, skills and experience, the expected annual salary range for this position is $300,000 - $475,000 USD.

• Visa sponsorship: We sponsor visas. While we can't guarantee success for every candidate or role, if you're the right fit, we're committed to working through the visa process together.

• Benefits: Thinking Machines offers generous health, dental, and vision benefits, unlimited PTO, paid parental leave, and relocation support as needed.