Founding Engineer

About the Role

Join a small, high-velocity founding team building multi-modal AI agents across voice, SMS, and email for a vertical B2B SaaS platform that reached seven figures ARR within months of launch. As a Founding Engineer, you'll own one of four core domains end-to-end — B2B product, agent quality, family graph infrastructure, or B2C consumer product — and make product decisions directly alongside customers with no PM layer between you and the work.

What You'll Do

• Own an entire product domain from architecture through daily production shipping.

• Join customer calls, synthesize feedback, and drive product decisions independently.

• Build and optimize multi-modal agents targeting sub-500ms voice latency, high SMS response rates, and persistent conversation state across channels.

• Establish architecture and quality practices for non-deterministic systems — evals, prompt versioning, guardrails, and drift detection.

• Work full-stack across React/Next.js frontends, Node.js backends, and Python voice services.

What We're Looking For

• 3–8 years of full-stack engineering experience with a strong record of shipping 0-to-1 products at high-growth startups, as a founder, or within new vertical teams at large tech companies.

• Strong proficiency in TypeScript (Node.js, React/Next.js) and hands-on production experience with LLM APIs or agent SDKs (e.g. Anthropic, OpenAI, Vercel AI SDK, or similar).

• Depth in at least one domain: production voice/SMS agents, long-running agent state and memory, B2B2C or marketplace product architecture, or agent evals and guardrails.

• Demonstrated ability to make product decisions independently and conduct customer discovery without a dedicated PM.

• Python experience with real-time voice pipelines (STT/TTS, low-latency audio) or evaluation tooling is a strong plus.

• Experience with infrastructure tooling such as Redis, job queues, observability platforms, or deployment pipelines is a plus.

• Founder background with real traction (revenue, funding, or acquisition) and clear articulation of lessons learned is a plus.

• Strong CS fundamentals; a degree from a rigorous CS program is a plus for candidates earlier in their career.

• Must be authorized to work in the US — no visa sponsorship available.

Compensation & Benefits

Salary range: $180,000 – $250,000 USD annually, plus equity. No visa sponsorship is available.

Location

On-site, five days per week in Chelsea, New York City.