Principal Software Engineer, Data Platform - Toast

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.

We are hiring a Principal Software Engineer to join our data platform (AAP) team in Dublin. The AAP team owns the foundational data infrastructure that powers Toast's analytics products and AI/ML capabilities: real-time streaming pipelines, a cloud-native data lakehouse, feature serving for ML-driven product experiences, and the infrastructure that enables product teams across Toast to build intelligent, data-driven experiences for our 170,000+ restaurant customers.

We are in the middle of a significant platform evolution: migrating to Apache Iceberg, standing up a new Feature Store, and scaling our streaming infrastructure to meet the demands of a rapidly growing business.

As a Principal Software Engineer, you'll contribute to the technical strategy for our most critical data platform initiatives - deep hands-on work with Spark and Iceberg, driving architectural decisions grounded in how these technologies actually behave under load, and helping shape the platform's touchpoints with the same care you'd bring to an external product. You'll work closely with other senior engineers and technical leads, influence adjacent teams, and mentor engineers across the organisation - articulating technical direction clearly to engineering, product, and leadership, and bringing people along through a significant platform transformation. Success looks like other engineering teams moving faster because of the platform you help build.

A day in the life (Responsibilities)

• Work hands-on with Spark, Iceberg, and our streaming infrastructure - diagnosing performance, reasoning through architectural decisions, and building systems that other teams depend on at scale
• Contribute to technical strategy for data platform initiatives alongside other senior engineers and technical leads, translating complex problems into clear direction and executable plans
• Design and evolve the platform's API surfaces so that engineers across Toast can self-service - adoption and ease-of-use are part of the job
• Influence adjacent teams and align stakeholders across engineering, product, and leadership on architectural decisions
• Mentor engineers on the team and raise the bar on engineering practices across the organisation
• Use AI tooling as a genuine force multiplier in your day-to-day work and help the team do the same

What you'll need to thrive (Requirements)

• 8+ years in software engineering with meaningful experience in data platform or distributed systems
• Deep expertise in Apache Spark and Apache Iceberg, not just operational familiarity
• Strong background in streaming infrastructure (Apache Kafka, Apache Pulsar, or similar) and cloud-native data platforms on AWS