Principal Software Engineer - AI Foundations

Toast, Inc.; Dublin; On-site; EUR 103,878 - 138,504; Full time

Job summary

Toast Tab, Inc. is seeking a Principal Software Engineer for their AI Foundations platform in Dublin. This role involves defining the technical architecture, leading full-stack development, and mentoring engineers. The ideal candidate has over 10 years of experience in scalable software systems and a strong full-stack background. This position requires at least two days per week at our Dublin office, and offers an opportunity to influence architecture decisions across the engineering team.

Qualifications

• 10+ years of experience designing and delivering scalable software systems.
• Demonstrated experience leading technical architecture for a platform or product.
• Proven ability to mentor engineers and raise the technical bar.

Responsibilities

• Define and drive the technical architecture for AI Foundations platform.
• Lead full‑stack design and delivery across AI key management and observability pipelines.
• Mentor and technically lead engineers through design and code reviews.

Skills

10+ years of experience designing and delivering scalable software systems

Technical architecture leadership

Mentoring engineers and raising technical standards

Building and deploying LLM-powered agents

Familiarity with AI coding assistants

Experience with MCP and agentic frameworks

Strong foundation in Java/Kotlin and TypeScript/React

Job description

AI Foundations is Toast’s internal platform team for AI. We build the infrastructure, governance, and developer tooling that makes AI a reliable, scalable force multiplier across the entire product development lifecycle.

As a Principal Software Engineer, you will set the technical direction for how we design, build, and evolve these systems, working full‑stack across the agentic workflows that employees across Toast depend on every day. This role is for someone who can drive architecture, raise the engineering bar across the team, and stay hands‑on building.

Responsibilities

• Define and drive the technical architecture for AI Foundations platform, spanning backend services, frontend tooling, and third‑party integrations.
• Lead full‑stack design and delivery across the LLM proxy, AI key management, observability pipelines, and internal plugin marketplace.
• Architect and deliver autonomous agents and MCP services that participate in the software development lifecycle.
• Set and uphold engineering standards across the team: code quality, system design, testing, and operational practices.
• Mentor and technically lead engineers across all levels through design reviews, code reviews, and pairing.
• Partner with product and platform leadership to shape the AI Foundations roadmap and translate strategy into executable technical plans.
• Collaborate closely with designers and product teams to translate UX concepts into polished, production‑ready frontend experiences.
• Serve as a key technical voice in cross‑team discussions, representing AI Foundations in architecture decisions across Toast engineering.

Requirements

• 10+ years of experience designing and delivering scalable software systems, with a strong full‑stack background spanning backend services and frontend or developer‑facing interfaces.
• Demonstrated experience leading technical architecture for a platform, product, or engineering team.
• Proven ability to mentor engineers and raise the technical bar of a team through standards, reviews, and hands‑on guidance.
• Experience building, deploying, or operating LLM‑powered agents or AI platform infrastructure.
• Familiarity with AI coding assistants (e.g., Claude Code, Cursor, GitHub Copilot) and experience extending them through custom plugins, skills, or hooks.
• Experience with MCP, tool use patterns, or agentic frameworks.
• Strong foundation in modern backend (Java, Kotlin, or similar) and frontend (TypeScript, React, or similar) technologies, with demonstrated experience building user‑facing product interfaces.
• Comfort with a rapidly changing technical landscape and a bias towards action over analysis paralysis.

Preferred Qualifications

• Familiarity with A2A (Agent‑to‑Agent) protocols and multi‑agent orchestration patterns.
• Experience with machine learning concepts, model evaluation, or ML infrastructure.
• Experience building developer experience platforms or internal tooling.
• Familiarity with observability tooling for AI/LLM systems (e.g., Langfuse, DataDog).

This role requires a minimum of two days per week in our Dublin office.

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