Member of Technical Staff
Full-stack engineer at a YC-backed San Francisco startup building Capy, an AI software engineer: you'll ship across React/Electron interfaces, a TypeScript/Effect backend on MySQL/Kubernetes/NATS, the agent loop, and the frontier model-provider layer. Onsite in SF, working by directing fleets of coding agents.
- Compensation
- $200K–$300K / yr
- Location
- SF
- Work setup
- Onsite
- Seniority
- Not specified
- Employment
- Not specified
- Experience
- Not specified
- Category
- Software engineering
- Posted
Skills
Must have
- Agent-native: already works with Claude Code, Codex, Cursor, etc. with sharp opinions on their shortcomings
- Fluent in TypeScript 7 on Node 24 and React in production
- Reads and writes typed functional code (Effect or similar) without a ramp
- Has shipped against MySQL, run something on Kubernetes, and touched a message bus like NATS
- Comfortable debugging at every layer (queries, websockets, Helm releases, tool calls) without a specialist
- Taste in interfaces, with shipped work that proves attention to motion, hierarchy, and empty states
- Independent product judgment: decides what to build without a PM or designer
- Verifies work, reads diffs, prefers deleting code over premature abstraction
- Based in San Francisco, working in the office
Nice to have
- Effect in production, or Rust experience
- Experience with sandboxed execution, VM images, remote desktops, or building/operating a git proxy
- Has built a model-provider layer or worked directly against Anthropic, OpenAI, and Gemini APIs
- Design-tool fluency (Figma or similar) on top of prototyping in code
- Public work: open source, posts, demos, an active account on X
- Founder or early-employee experience
Full description
About Capy
We're building the AI software engineer you hand real work to. A thread starts from Slack, Linear, the web app, the desktop app, or the API; Capy makes the change on a cloud machine or right on your own laptop, office Mac mini, or any device you've paired, opens the pull request, and handles CI and review feedback until it merges. Work moves between your devices and the cloud mid-thread, big work splits into parallel agents across those machines, a review agent reads every PR, and automations run on a schedule or on platform events. The age of the solo coder is over: developers stop babysitting single agent sessions and start orchestrating fleets of agents, together with their team.
We're a small team in San Francisco, backed by Y Combinator and tier-1 investors, shipping to teams that run Capy on production codebases every day. We build Capy with Capy: our own PRs, reviews, and automations run through it.
The role
AI coding is a crowded market now, and developers expect first-minute magic and a quality bar that holds across every surface. Meeting that bar means you will have to own the entire product experience and craft it with care.
"Full stack" here means the whole width of Capy: the interfaces developers direct agents from, the agent loop and its tools, the backend the loop re-plans from, the infrastructure the machines boot on, and the layer that talks to every frontier model. You'll make product decisions without a PM, design without waiting on a mockup, and solve the hard engineering problem yourself rather than handing it off. This is a role for people who build with taste and feel the gap between what exists and what should, then close it.
What you'll do
- Ship across the whole stack. One day is a new tool in the agent loop, the next is the React surface that shows what it did, the migration behind it, and the Kubernetes change that ships it.
- Set the standard for agent UX. Threads, tasks, diffs, reviews, live machine desktops streamed from our Rust remote desktop: twenty-five agents running at once need an interface that stays legible.
- Design in code. Take a feature from rough idea to a polished, animated, keyboard-first interface in the React web app and Electron desktop app.
- Build the backend the agent runs on. Effect services over MySQL (Vitess on PlanetScale), realtime fan-out over NATS, the typed API and protocol every client shares, the git proxy, the worker that drains threads.
- Push what the agent can do. New tools, better verification, tighter loops with CI and review, smarter task orchestration, and the provider layer across Anthropic, OpenAI, Gemini, and the rest.
- Run the infrastructure. The Kubernetes clusters and IaC that deploy Capy, and the VM images and sandbox platform every cloud machine boots from.