Rebuilding the Vimocity web app

Problem

New features were being built in a new monorepo. The web portal was not — it sat on the old structure, and everything we wanted to improve there was blocked behind a migration nobody had time to do. We were running two frontends that looked and behaved like two different products.

That gap was not going to close on its own. Rebuilding meant every page: the content library, challenges, movement routines, video collections, user-created playlists, site settings, and user settings.

What I did

• Loaded both repositories into Claude Code and had it read the old platform page by page — the logic, the API calls, and the database links each page actually depended on. Working out what a legacy page really does is most of the work in a migration, and it is exactly what an agent is good at.
• Rebuilt each page in the monorepo from VimUI components and tokens, wired to the same APIs and database. Functional equivalence first: same behavior, same data, new foundation.
• Held the whole rebuild to the standards from my guardrails work — token use, component structure, and accessibility rules, checked automatically. The rules I had written for people turned out to be what made an agent's output reviewable.
• Redesigned the content library on the way through, into a searchable explore page. Migration was the opportunity to fix discovery rather than port a problem forward.
• Modernized the homepage and settings pages, which had accumulated patterns that no longer matched how anyone expects a web app to behave.
• Handed each rebuilt section to engineering to review and harden — an agent misreads things, and the review is what catches it.

Outcome

• Every page of the portal is live on one codebase, consistent with the new features it used to sit beside.
• About 80% of the frontend code I built survived review into production. Backend calls and database queries were improved in the same pass — the migration was a chance to clean up old code, not just move it.
• The portal works on mobile web. VimUI components carry the responsive and accessibility work with them, and the old platform had neither.
• Changes no longer need me. A product manager or engineer can now change a page using VimUI and the design rules, without a designer or a frontend developer in the loop — which is the point of writing the rules down.
• Every value on every page resolves to a token, so a change to the system is a change to the product rather than a ticket to make it one.