Principal Software Engineer, Data Platform

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
• Experience designing internal platforms and developer-facing abstractions - you think about your platform's users as carefully as product engineers think about end users
• Demonstrated ability to drive technical alignment across multi-team environments, including the communication work that makes architectural changes actually stick
• Databricks experience is a bonus but we care more that you understand what's running underneath it

Our tech stack

Our data platform runs on AWS and spans Apache Iceberg for table format and lakehouse architecture, Apache Kafka and Pulsar for real-time streaming, Apache Spark for data processing, and DynamoDB and Postgres for operational data stores. We are migrating from legacy ETL patterns toward a modern, cloud-native data lakehouse and building out Feature Store capabilities to power ML-driven product experiences. Our backend services are primarily Kotlin and Java.

**This is a hybrid role requiring in-office collaboration two days per week in our Dublin office.**

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.

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