Fullstack Engineer - Cofounder

About Cofounder

Cofounder is an autonomous agent platform that connects to your tools (Gmail, Slack, Notion, Linear, Google Workspace, GitHub, Airtable, etc.) to run workflows end to end. We’re building the operating system for one-person, billion-dollar companies.

What you’ll own

• End-to-end product work across the agent experience: flows, integrations, and UI/UX

• Flows: creation, editing, run criteria, execution reliability, and observability

• Integrations: add new integrations and deepen existing ones

• UI/UX: work on novel, interesting ways of building human <> agent interactions

• Product sense for complex UX: making powerful systems feel simple and reliable

• Ship features across the stack with a tight feedback loop from real users (frontend + backend)

• Improve performance, reliability, and cost across agent runs and flow execution

• Build instrumentation, analytics, and developer tooling to speed up iteration

• Maintain a high bar for code quality, tests, observability, and documentation

Requirements

• 4+ years building and shipping user-facing products end to end

• Frontend: React/Next.js (or equivalent), TypeScript; component-driven development, performance profiling, accessibility, data fetching/state, optimistic UI and cache invalidation

• Backend: Python FastAPI, background workers/queues, webhooks, Postgres (or similar) schema design, transactions, migrations

• Solid testing and observability habits (unit/integration tests, metrics, traces, structured logs)

• Bias to ship: scope thin slices, deliver quickly, instrument, iterate

Nice to have

• Event-driven architectures (Inngest/Temporal), WebSockets/real-time UIs

• LLM/agent experience: tool-use patterns, prompt hygiene, guardrails, evaluation

• Infra familiarity (Render/Modal/Supabase/Redis Cloud or equivalent), CI/CD, feature flags

Why join

• Ship directly to engaged users; your work is visible and high-impact

• Build the core of an autonomous agent platform with real integrations and real workloads

• Small, elite team; high ownership; fast decisions; zero bureaucracy