Senior Frontend Engineer (React/TypeScript)

Location: Hybrid in London or Paris, with three days per week in the office and visits to the other office every four to six weeks

Company

H builds AI agents that use computers like people do in browsers and on desktops.

What you will do

• Build the H Platform web application for deploying agents, monitoring live runs, and replaying actions step by step.
• Build and improve HoloTab, a Chrome extension that controls the browser on a user's behalf.
• Design interfaces for live agent runs, replay, streaming data, and user control.
• Extend the Python APIs required to support front-end features.
• Establish shared component patterns and make long-running workflows easier for FDEs and customers to deploy and monitor.

Requirements

• Senior-level experience shipping production products with React and TypeScript.
• Ability to make the API changes required by a feature in addition to building its UI.
• Ability to write correct concurrent code and handle live, asynchronous data in the interface.
• Strong product judgment and interest in designing interfaces around real user needs.
• Experience with Python.
• Availability to work three days per week from the London or Paris office.

Nice to have

• Experience with Chrome extensions or the Chrome DevTools Protocol.
• Experience building real-time interfaces with streaming, SSE, or WebSockets.
• Experience with design systems or component libraries.
• Experience with FastAPI or a similar Python API framework.
• Experience with Preact and Vite.

Culture & Benefits

• Product Engineering role working closely with the owners of the H Platform and HoloTab.
• Users include Forward Deployed Engineers, technical customers, and daily HoloTab users.
• Competitive package.
• Work is evaluated through shipped user-facing features, front-end quality in CI, and usability of agent monitoring and control.

Hiring process

• 30-minute call with the Talent team.
• 60-minute coding interview.
• Approximately two-hour take-home front-end exercise followed by a 45-minute review.
• 30-minute closing conversation.