Lead Frontend Engineer

The company Canvas is a browser-based AI rendering platform for architects and designers that went live earlier this year after previous product iterations were tested across firms including Zaha Hadid Architects, KPF, and David Chipperfield Architects. Today, over 100,000 designers use it to generate more than a million images every month.

We're looking for a Lead/Principle Frontend Engineer to take ownership of the company Canvas's frontend: a real-time, collaborative canvas application that's closer in spirit to Figma or Miro than a typical SaaS app. It's React (Next.js), with a WebGL canvas at the centre, multiplayer state powered by WebSockets and yjs, and a steady drumbeat of new 2D and 3D features shipping regularly.

About the company: We're a lean, design-led team building what we believe is the most exciting frontend product in architecture today: AI rendering that turns any starting point (a sketch, CAD model, collage, or photo) into a high-quality visual in seconds, inside a collaborative canvas that designers can share with their colleagues and stakeholders. We've raised substantial pre-seed and seed funding from leading investors in the space, and work in close partnership with some of the world's most prestigious architecture firms. Design is at the core of our mission - in our product, in our tools, and in how we work.

The company is a startup with a fast-growing product, and the role reflects that. There's a lot to build, the bar is high, and the days are full. That's the trade we make for the impact, ownership, and equity that come with being early. It's not the right fit for everyone, and that's completely fair - but if you're energised by hard problems, a team that cares deeply, and work that real designers rely on every single day, you'll thrive here.

What you'll work on: The canvas is the heart of the product, and it's a real engineering challenge. You'll spend your time on things like:

• The canvas runtime itself: keeping interaction smooth and robust as users place tens, then hundreds of generations, references, and 3D models on a single board.
• Multiplayer state: using yjs and WebSockets to keep collaborators in sync, with rock-solid undo/redo, presence, and conflict resolution.
• AI generation flow: async generation, streaming previews, optimistic UI, and surfacing useful feedback when a render takes a few seconds or much longer.
• 2D and 3D primitives: building the canvas's interaction model around images, masks, and manipulable 3D models, using react-three-fiber.
• The design system and visual language: working closely with our designer to ship features that feel as considered as the firms our customers work at.

You'll work directly with our founders and a small team of engineers and designers. We're small enough that you'll have a real say in the architecture and meaningful ownership of what we build.

We'd love to hear from you if you have:

• Extensive production experience with React (including Next.js): you've shipped complex, performant applications and have strong opinions about frontend architecture.
• Strong state management chops: comfortable with the trade-offs between Zustand, MobX, Redux, and friends, and able to manage genuinely complex client state.
• Experience with real-time collaboration: WebSockets for sure; yjs (or another CRDT) is a strong plus.
• Working knowledge of three.js / WebGL: ideally via react-three-fiber. Doesn't need to be your primary skill, but you should be comfortable in the territory or excited to live there.
• A strong eye for design and product: you can fill in gaps when wireframes aren't there, push back when something doesn't feel right, and use a design system without hiding behind it.
• Performance instincts: you've optimised a frontend that pushed against the browser's limits and you know where to look first.
• Full-stack comfort: particularly around API design - you're happy reaching into the backend when a feature calls for it.

Nice to have:

• Experience working on creative tools or design software (Figma, Miro, Spline, tldraw, or similar).
• Familiarity with CAD or 3D modelling tools (Blender, Rhino, 3DS Max) or computer graphics in general.
• Experience designing and shipping products with i18n / l10n requirements.

Why this role: You will work on a product that real architects use every day: including teams at leading architecture studios. The technical problem is genuinely novel: real-time collaborative canvas + AI + 3D, with hundreds of thousands of users already pushing on it. Small team, big surface area: you'll own the frontend in a real sense, not be one of fifty React engineers in a SaaS org. Meaningful equity: we firmly believe you should share in the company's future success - generous options are included alongside salary.

What we offer: This is a full-time hybrid role: 3 days a week in our London or Bristol office, and 2 days a week from home (in the UK). Stock options, 25 days holiday, plus a day off during your birthday week, private medical, dental, and vision insurance, flexible well-being allowance (e.g. gym membership), frequent company socials and events. Compensation Range: £80K - £100K.