Founding Software Engineer

The Role

Raydar is recruiting for this role on behalf of our client. Own the design and delivery of application and backend features for a widely used consumer product, working side by side with company leadership. The work centers on applied AI systems and the infrastructure behind them, in a compact, in-person environment.

What You'll Do

• Build and refine the core AI agent framework , covering tool use, memory, prompting, retrieval and evaluation.
• Take features from architecture through launch and ongoing iteration across the user-facing app and backend services.
• Partner directly with the founders to shape a simple , polished user experience.
• Extend agent capabilities with sandboxed tooling and backend and database infrastructure designed to scale.
• Help deploy and tune GPU infrastructure, including fine-tuning and serving open-source language models.
• Weigh tradeoffs between speed, spend, stability, data protection and usability when making technical decisions.
• Contribute to future product initiatives as the company grows.

What We're Looking For

• Solid engineering background across the full stack or on the backend.
• Hands-on experience building an agentic system that goes beyond simple LLM SDK calls, including tool calling, memory and system prompts.
• Practical experience with open-source language models, such as serving, fine-tuning or evaluation.
• A history of building and shipping your own product, whether a startup, side project or open-source work, with measurable results such as users, revenue or adoption.
• A public code portfolio showing personal projects and recent, steady activity.
• Clear, effective communication.
• Comfort taking ownership of whatever needs attention in a lean team.
• Willingness to work an intense early-stage schedule, up to 7 days a week with 5 in the office.

Bonus Points

• Founding or early engineer experience at an applied AI or consumer startup.
• Strong consumer product instincts.
• Open-source contributions.
• A long coding history that predates AI coding tools.

Location And Work Model

• New York, NY, United States
• On-site, 5 days per week in the office
• Full-time

Compensation, As The Posting Describes It

• Equity