Fullstack Engineer - Cofounder
Department: Product - Cofounder
Location: New York
Compensation: $225K – $300K • 0.25% – 0.6%
Employment Type: FullTime
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
There are more than 50,000 engineering jobs:
Subscribe to membership and unlock all jobs
Engineering Jobs
60,000+ jobs from 4,500+ well-funded companies
Updated Daily
New jobs are added every day as companies post them
Refined Search
Use filters like skill, location, etc to narrow results
Become a member
🥳🥳🥳 452 happy customers and counting...
Overall, over 80% of customers chose to renew their subscriptions after the initial sign-up.
To try it out
For active job seekers
For those who are passive looking
Cancel anytime
Frequently Asked Questions
- We prioritize job seekers as our customers, unlike bigger job sites, by charging a small fee to provide them with curated access to the best companies and up-to-date jobs. This focus allows us to deliver a more personalized and effective job search experience.
- We've got over 200,000 jobs from 15,000+ vetted companies. No fake or sleazy jobs here!
- We aggregate jobs from 15,000+ companies' career pages, so you can be sure that you're getting the most up-to-date and relevant jobs.
- We're the only job board *for* software engineers, *by* software engineers… in case you needed a reminder! We add thousands of new jobs daily and offer powerful search filters just for you. 🛠️
- Every single hour! We add 2,000-3,000 new jobs daily, so you'll always have fresh opportunities. 🚀
- Typically, job searches take 3-6 months. EchoJobs helps you spend more time applying and less time hunting. 🎯
- Check daily! We're always updating with new jobs. Set up job alerts for even quicker access. 📅
What Fellow Engineers Say