Science Metal Stablecoin — mint, swap and earn platform

Context

SMS is a stablecoin platform. Users mint and redeem the token against bank and crypto accounts, swap, stake, and manage who on the team can approve what. When I joined, the frontend carried a lot of structural debt — business logic sat wherever routing put it, nobody trusted the generated API types, component trees were duplicated, and commits had no convention. I wrote a detailed architectural review with a concrete target layering and then moved the ecosystem onto it.

What I did

• I rebuilt the user-facing app as isolated business modules — deposit, withdraw, swap, stake, approvals, team management — where each one keeps its own state, screens and validation and never reaches into another, and that single rule is what made the whole thing predictable to work in. Leading the team through the change was half the job: I split the target architecture into independent tasks, matched them to whoever knew the area best, and reviewed every diff against the new layering, so the roadmap never paused while the foundation was being replaced.
• Multi-step money flows got a custom Stack Navigator I wrote for them, with typed steps, an undo history and animated transitions between stages, so a withdrawal that spans several screens behaves as one flow. Balances and approvals update live over SSE, and the transaction history is a virtualized table that pages through years of records with filtering that genuinely works at that scale.
• Security had to match a financial product, so it got passkeys, two-factor with recovery codes, role-based guards, an idle logout, and token refresh that runs quietly in the background.

Outcome

That review became the architecture standard across the ecosystem. Modules stay independent, every app shares the same conventions, and new work arrives as new modules the team builds in parallel rather than edits buried deep in old code.