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, building, and operating highly scalable, mission-critical distributed systems and SaaS products (ideally AWS-hosted). • Proven track record of leading complex technical initiatives and delivering robust software architecture from design to production. • Strong enthusiasm for agentic development practices, LLM integration, and modern software paradigms. • Balanced expertise: Ability to design high-level technical solutions on a whiteboard while remaining deeply connected to code-level execution and system performance. • Effective communication: Ability to articulate complex technical ideas clearly to both technical peers and product leadership. What Will Help You Stand Out (Nice to Haves) • Experience building systems that leverage LLMs, autonomous agents, or ML models. • Hands-on experience with enterprise integration frameworks (e.g., Apache Camel) or event-driven messaging systems (e.g., Apache Pulsar). • Experience establishing robust CI/CD, testing, and deployment strategies for complex systems. • Domain knowledge in workforce management or restaurant operations. Location: Remote (within Ireland) or Hybrid (Dublin) AI at Toast At Toast, one of our company values is that we're hungry to build and learn. We believe learning new AI tools empowers us to build for our customers faster, more independently, and with higher quality. We provide these tools across all disciplines, from Engineering and Product to Sales and Support, and are inspired by how our Toasters are already driving real value with them. The people who thrive here are those who embrace changes that let us build more for our customers; it’s a core part of our culture. Our Total Rewards Philosophy We strive to provide competitive compensation and benefits programs that help to attract, retain, and motivate the best and brightest people in our industry. Our total rewards package goes beyond great earnings potential and provides the means to a healthy lifestyle with the flexibility to meet Toasters’ changing needs. Learn more about our benefits at https://careers.toasttab.com/toast-benefits. How Toast Uses AI in its Hiring Process Throughout the hiring process, our goal is to get to know you. We use AI tools to support our recruiters and interviewers with tasks like note-taking, summarization, and documentation of interviews to ensure they can be fully focused on your conversation. All hiring decisions are made by people. We ask that you complete interviews and assessments on your own, without real-time AI tools, recording, or transcription bots, unless we tell you otherwise in advance. To learn more: https://careers.toasttab.com/ai-in-hiring Our Approach to Hybrid Working We embrace a hybrid work model that fosters in-person collaboration while valuing individual needs. Our goal is to build a strong culture of connection as we work together to empower the hospitality community, regardless of location. Please visit the Locations page on our career site to learn more about our in-office expectations by region: https://careers.toasttab.com/locations-toast People Are the Secret Ingredient in Our Recipe for Success At Toast, our employees are our secret ingredient—when they thrive, we thrive. The restaurant industry brings together people with a wide range of backgrounds, experiences, and perspectives, and we value that same breadth at Toast. We strive to build a culture grounded in authenticity, respect, and humility, where every Toaster has a real opportunity to grow, contribute, and do their best work—raising the bar in delivering exceptional experiences for our customers and each other. Apply today! Toast is committed to creating an accessible and inclusive hiring process. As part of this commitment, we strive to provide reasonable accommodations for persons with disabilities to enable them to access the hiring process. If you need an accommodation to access the job application or interview process, please contact candidateaccommodations@toasttab.com. ------ For roles in the United States, it is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.