Principal Machine Learning 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. Toast is looking for a hands-on Principal Software Engineer to join the AI & Strategy Engineering team. In this role, you will be a primary builder of 0-to-1 tools designed to revolutionize how our sales teams operate. This isn't about maintaining legacy systems; it’s about writing the code and building the intelligence models that eliminate friction across the Go-To-Market stack. Working under a Senior technical leader, you will be responsible for the "heavy lifting" of backend engineering and Machine Learning implementation. You will bridge our custom quoting software and Salesforce with intelligent, agentic workflows that allow sales users to make faster, data-backed decisions. A day in the life (Responsibilities) Hands-on Execution: Spend the majority of your time "hands-on-keyboard," architecting and coding high-performance backend services and ML pipelines. 0-to-1 Development: Build and prototype new internal products from scratch that leverage LLMs and Agentic AI to automate account research, lead prioritization, and complex quoting logic. Core Intelligence Models: Design and implement ML models that provide real-time recommendations to sales users, reducing manual entry and increasing deal velocity. Infrastructure Integration: Develop the backend connective tissue between our custom quoting engine, Salesforce, and internal data lakes to ensure a seamless, low-latency end-to-end experience. Technical Problem Solving: Act as a domain expert to solve complex synchronization and architectural challenges across the GTM stack, ensuring systems are scalable and resilient. Quality & Mentorship: Drive engineering excellence through rigorous code reviews, automated testing, and by modeling best practices for SE1-SE3 engineers on the team. Build Great Products: Deliver significant core capabilities that have broad impact; take high-level goals and turn them into sequenced, production-ready code. Problem Solve: Anticipate shifts in product needs and build flexible, decoupled backend systems that can evolve with our AI strategy. Deliver Quality: Ensure the reliability of GTM tools by building deep observability into every service you ship. What you'll need to thrive (Requirements) Deep Backend Expertise: Extensive experience in backend languages (Java, Go, Python) with a track record of building complex, distributed systems. Applied AI/ML Skills: Practical, hands-on experience deploying Machine Learning models and building with LLMs (e.g., LangChain, RAG architectures, or Model Fine-tuning) in a production environment. Technical Complexity: Experience building or deeply integrating with complex enterprise software, specifically custom quoting engines or CRM internals (Salesforce Apex/LWC). Systems Architecture: Ability to design event-driven architectures and manage data flow across disparate systems with high integrity. Education: Bachelor’s or Master’s degree in Computer Science, or a related technical field. What will help you stand out (Nonessential Skills/Nice to Haves) Experience building internal "Sales Tech" or "Fintech" tools that directly impact revenue. Familiarity with AWS data services (SageMaker, Lambda, SQS). A passion for removing "human-in-the-loop" friction through intelligent automation. 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