Founding Engineer

Our client is a fast-growing AI startup building multimodal sales and lifecycle agents for youth enrichment businesses and families. Its voice, SMS, and email agents help sports programs, academic centers, camps, and other providers answer families instantly, drive enrollment, and grow long-term relationships. The seven-person company was founded by former Uber and DoorDash engineering leaders, has raised $3M, and reached seven figures of ARR in its first 4.5 months. This is a true founding engineering seat on a small, high-velocity team, with two hires planned. You will own one of the company's core product domains end to end, make product decisions directly with founders and customers, and ship production features without a separate PM layer. What you'll do: Own the B2B operating system, multimodal agent layer, family graph and memory system, or a new consumer product. Join customer calls, synthesize feedback, make roadmap tradeoffs, and ship without waiting for a PM. Build reliable voice, SMS, and email agents with low latency, strong response quality, and long-running state across channels. Establish evaluation, prompt-versioning, guardrail, and drift-detection systems for nondeterministic AI behavior. Work full stack across React and Next.js frontends, Node.js services, and Python voice pipelines. Ship production improvements daily while raising the bar for architecture, product quality, and engineering velocity. What we're looking for: 3 to 8 years of full-stack product engineering experience. Strong production experience with TypeScript, Node.js, React, and Next.js. Evidence of shipping a zero-to-one product at a high-growth startup, as a founder, or on a new-product team inside a larger technology company. Depth in production voice or messaging agents, long-running agent state and memory, B2B2C or marketplace products, or agent evaluations and guardrails. Direct experience building products with LLM APIs or agent SDKs such as Anthropic, OpenAI, Vercel AI SDK, or Mastra. Strong product judgment, high agency, comfort talking with customers, and the ability to make good decisions without extensive structure. Willingness to work five days per week from the Chelsea, New York City office. Candidates outside New York must be willing to relocate. Existing OPT or H-1B transfers may be considered. Compensation and benefits: $180,000 to $250,000 base salary. Competitive founding-stage equity. Direct product ownership and daily access to the founders and customers. Career flexibility to grow into leadership or remain on a senior individual-contributor track. Full-time, in-person role in Chelsea, New York City. #J-18808-Ljbffr Socket.dev