Senior Software Engineer, AI

Description

The company runs an AI-powered global work platform that lets businesses hire, pay and manage employees in more than 185 countries, backed by over a decade of compliance experience.

The team is building Alfie, a conversational AI assistant, and is looking for a Senior Full-Stack AI Engineer to help decide what AI-native software should look like.

The role is fully full-stack and you would own features from the APIs and data models through to the user interface. It reports to the Engineering Manager, with day-to-day work led by the Staff Software Engineer.

Team members are accountable for results and impact, and the company's values guide how people work across borders.

Responsibilities

• Design, build and ship full-stack features for Alfie, owning them from the data model and API layer through to the user experience.
• Build and run backend microservices in TypeScript or Python on Postgres and AWS, deployed on Kubernetes, with clean contracts and APIs for agentic workflows.
• Occasionally use Lambda for asynchronous or infrequent processing that users do not see.
• Build the React/TypeScript frontend, including conversational and streaming interfaces, aiming for an AI experience that is more than good enough.
• Apply your experience with LLM and agentic systems, covering prompt design, tool calling, multi-step reasoning and evaluation, to shape how the assistant behaves and how that shows to users.
• Design for failure: recovery paths, human handoffs, and what users see when the assistant is unsure or fails.
• Prototype and propose new interaction patterns as models and agent capabilities change.
• Build observability and evaluation into the AI systems so you can see how agents behave in production and improve them using evidence.
• Debug production issues end to end, both standard backend and frontend problems and AI-specific ones such as poor model output, latency and dropped tool calls.
• Set the standard with clean, well-tested, maintainable code, mentor junior engineers, and contribute to design and code reviews.
• Work with product managers, designers and other engineers to deliver features end to end.

Requirements

• 7+ years of professional full-stack software engineering experience, with real depth on both backend and frontend.
• Proficiency in TypeScript or Python and strong experience with database-backed services on Postgres or a similar relational database, including schema design, query writing and performance.
• Strong command of modern React/TypeScript, including how frontends connect to backend services, APIs and real-time or streaming data.
• 1+ years of hands-on experience building LLM-powered or agentic products, including designing how an agent reasons, uses tools and returns control to the user.
• Experience shipping a conversational assistant, such as a chatbot, copilot or AI assistant, that real end users relied on, and the ability to explain what users experienced when it failed or confused them.
• Solid understanding of LLM design patterns, prompt engineering, and observability for agentic systems.
• Experience building and deploying services in containers on Kubernetes or comparable orchestration, and comfort with AWS.
• Solid computer science fundamentals and system design skills, with the ability to reason about data structures, APIs and architecture and make tradeoffs at scale.
• A track record of building products beyond standard CRUD apps and dashboards, with real craft, polish or a distinctive user experience.
• A lean mindset: you cut waste, improve workflows and iterate quickly on feedback.
• Comfort working collaboratively and remotely at pace in a fast-changing field where best practices for AI-native software are still being found.

Conditions

Remote role.

Equal opportunity employer: hiring decisions are based on qualifications, merit and business needs, without discrimination on protected grounds.

Benefits

• Flexible time off.
• Parental leave.
• Health and dental insurance where applicable, covering you and your family.
• Retirement savings plan and an employee incentive plan.
• Benefits vary by role and location; see the career page for details.