Founding Engineer

About the Role

This is a founding engineering seat at a fast-growing AI-native startup building multi-modal sales agents across voice, SMS, and email for a focused vertical market. You will own one of four core domains end-to-end, making product and architecture 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, covering areas such as B2B product, agent quality, family graph infrastructure, or B2C consumer product.

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.

Design and maintain quality systems for non-deterministic AI behavior, including evals, prompt versioning, guardrails, and drift detection.

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

What We're Looking For

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

Production proficiency in TypeScript with hands-on experience in Node.js, React, and Next.js.

Direct production experience building with LLM APIs or agent SDKs such as Anthropic, OpenAI, Vercel AI SDK, or Mastra.

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

Comfort making independent product decisions and conducting customer discovery without dedicated PM support.

Experience with low-latency system design and non-deterministic system behavior at production scale.

Python experience with real-time voice pipelines (such as LiveKit or Deepgram) or evaluation tooling is a strong plus.

Familiarity with infrastructure tools such as Redis, BullMQ, Vercel, Render, Sentry, or PostHog is a plus.

Strong CS fundamentals, with a relevant degree or verifiable founder traction (revenue, funding, or acquisition) serving as a positive signal for candidates earlier in their career.

No visa sponsorship is available for this role.

Compensation & Benefits

Base salary: $180,000 to $250,000 USD annually. Equity is available given the founding nature of the role. Visa sponsorship is not available.

Location

On-site, five days per week in Chelsea, New York City . Candidates must be based in or able to commute to NYC.