Principal Software Engineer

Toast creates technology to help restaurants and local businesses succeed in a digital world, helping business owners operate, increase sales, engage customers, and keep employees happy. Your mission is to lead the architectural design, technical execution, and implementation of AI agents and infrastructure for Toast's Team area within our FinTech line of business. The Team area is a mission-critical space on which our restaurants rely to manage their staff and optimize their labor. As a Principal Engineer, you will serve as a key technical leader in the group, driving modern architectural patterns—including spec-driven development and agentic workflows—to deliver high-impact software. A Day in the Life (Responsibilities) Define and execute the technical architecture for AI agents within the Team domain, ensuring systems are scalable, reliable, and secure. Partner closely with Engineering Managers and Product Managers to translate product roadmaps into robust technical designs and deliverables. Maintain a strong hands-on presence, writing code, prototyping new patterns, and resolving complex technical bottlenecks under load. Collaborate with Principal and Senior Principal Engineers across Toast to align on best practices, agent patterns, and spec-driven development paradigms. Guide, mentor, and elevate engineers within the Team area, fostering a culture of technical excellence and continuous learning. What You'll Need to Thrive (Requirements) 10+ years of experience designing