Onix is the Personal Intelligence platform. Each onix is a small language model trained exclusively on a single expert’s private corpus: clinical notes, unpublished research, proprietary methods that have never been on the internet and never will be. Fully isolated, never bleeding across experts.

Generic AI averages the internet. Onix lets you summon the actual judgment of a health and wellness expert who has spent a career on your problem, private and personal: names already live on the App Store include Dave Rabin, Mark Sisson, Ashley Koff, William Li, and Elissa Epel.

We need someone to own where the design of Onix goes next: apps, platforms, surfaces, flows, screens, UI/UX, and the design system underneath them.

The ideal candidate has experience building consumer mobile products with heavy daily usage. We need someone used to environments where design decisions survive millions of live sessions, rather than just looking good in a portfolio. You operate at two altitudes: driving the narrative of a user flow, and sweating the four pixels that make a button feel right. You’ll be building this collaboratively, working in person with our team in Old Montreal.

What You Will Do

• Product design. Own the iOS app end to end, from first open through the hundredth session.
• Design system. Own the foundation: color, type, spacing, and components, so engineering, product, and marketing can build from it directly.
• Ship with engineering. Sit next to the people building your work, specify clearly, review builds, and hold the line on the details that matter.
• Brand visual system. Own our visual identity at the system level, and work closely with brand, marketing, growth, and product so every surface, not just the app, tells one story.
• Leadership reviews. Present and defend design decisions to the founders regularly, work with the feedback, and come back with something better.

Who You Are

• Shipped consumer mobile products with real usage behind it, and you can walk us through the decisions, not just the screens.
• Built or substantially owned a design system, including the rules and the documentation behind it.
• Hold strong opinions with reasons, and defend them under direct feedback from the team, especially when those opinions are challenged.
• Use AI in your process and still hold craft and taste as non-negotiable.
• Prefer to stay hands-on and ship the work yourself.

This Role is NOT For You If:

• You want a remote job. We build together in person, in Old Montreal.
• You want to build and manage a design team rather than do the work yourself.
• You would rather avoid direct critique than take it and get better.

What Success Looks Like

• You have shipped meaningful changes to the app, not just explorations.
• Our design system has written usage rules, and everyone builds from it independently.
• Design decisions land with you directly.
• Acquisition, activation, and retention have improved on changes you designed.
• Design reviews with the founders move from fixing problems to shaping what comes next.