Senior Full-Stack Engineer (Backend-Leaning)

About The Company
We're a 12–14 person AI-native team in San Francisco building a personal AI assistant for knowledge workers — something closer to "Cursor for knowledge work" than a chatbot. The system understands user context, curates and prioritises work, operates in the background, and delivers supervision-ready output rather than waiting to be prompted.
We've raised $30M in seed funding from Spark Capital, Felicis, and Y Combinator — one of the largest seed rounds in YC history. The team is composed of former founders, CTOs, and high-agency builders. High ownership is the norm, not the exception. We're well-positioned post-fundraising and building toward a major public launch.
We're hiring a Senior Full-Stack Engineer (backend-leaning) to join us in person in San Francisco. This is a senior, product-minded engineering role with end-to-end ownership — not a ticket-taking position. Feature requests are assigned to individuals, and you own them fully from conception through architecture, implementation, shipping, and iteration.
You'll handle backend-heavy work with some infrastructure and DevOps responsibility, implement basic frontend functionality when needed, and work directly with users — engineers here onboard users themselves. You'll translate user feedback into experiments and shipped improvements, operating in a fast-moving, ambiguity-tolerant environment where velocity is the product.
What You'll Work On
End-to-end feature ownership
Own features from conception through architecture, implementation, shipping, and iteration. No handoffs — you see it through.
Backend and infrastructure
Handle backend-heavy work with some infrastructure and DevOps responsibility. You're comfortable owning the stack, not just writing application code.
User engagement
Work directly with users — engineers onboard users themselves here. Translate what you hear into experiments and shipped improvements.
AI system development
Build on top of AI models and agentic workflows. Understand agent loops, model interaction patterns, and how to build reliable systems on top of non-deterministic outputs.
TECH STACK
TypeScript, React, Next.js, Node.js, PostgreSQL, Cloudflare, AWS and additional infrastructure providers, multiple AI model integrations.
What We Look For
Senior full-stack experience, backend-leaning
A strong track record building and owning production systems end to end. You lean backend but can handle frontend when needed — no layer of the stack intimidates you.
Systems design depth
You think about how systems scale, fail, and integrate before you write the first line. Architecture decisions are yours to make and defend.
Infrastructure ownership
Comfortable owning infrastructure — not just deploying code, but understanding what's running it and why.
AI application experience
Experience building AI-enabled products. You understand agentic workflows and model interaction patterns from building with them, not just reading about them. Deep ML expertise is not required — but you cannot be starting from zero.
High agency
You operate independently, move fast with incomplete information, and don't wait for perfect specs. Ambiguity is the default — you're comfortable in it.
LOCATION
In-person only — San Francisco office. Must be US-based or willing to relocate. European candidates may be considered for O-1 visa sponsorship.
Compensation
Salary
$200,000 – $240,000 depending on experience.
Equity
Meaningful equity included.
Requirements

• Senior-level experience as a full-stack engineer (backend-leaning)
• Strong systems design skills
• Comfort with infrastructure ownership
• Experience building AI-enabled products
• Ability to operate independently with high agency

Required Skills

• Understand AI applications and agentic workflows
• Have experience with agent loops and model interaction patterns
• Be able to ramp quickly on AI-heavy systems
• TypeScript
• React
• AWS + additional infrastructure providers
• AI model integrations

Benefits

• equity

Salary:
200000 - 240000 SalaryCurrency.USD