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Next‑gen local development workflow

Modernized Next.js local dev with a unified proxy, presets for app state, and flexible mocking to speed up iteration.

Company: Credit Karma

nextjsdxtooling
Summary
A faster, simpler local dev setup for Next.js—single server + proxy, state presets, and powerful mocking to speed iteration without backend dependencies.

Rebuilt the local development loop for modern Next.js apps—fewer moving parts, faster feedback, and powerful state controls for real-world testing.

Highlights

  • Single Next.js dev server plus a lightweight local proxy (one port, no CORS headaches)
  • Admin UI to toggle presets like authenticated/unauthenticated or device modes
  • Dynamic network mocking using a dedicated Mock Service Worker (MSW) server
Rendering diagram…
Unified local dev workflow with proxy and presets

Why clients care

Faster iteration means more product shipped with fewer regressions. Teams get a consistent, batteries-included setup that mirrors production behaviors without backend dependencies.

What changed

  • Simplified multi-process legacy setup into a single ergonomic workflow
  • Standardized project layout and linting via framework conventions
  • Enabled high-fidelity E2E testing locally (including device simulation)

Result

Developers spend less time on environment quirks and more time delivering features—while testing realistic scenarios from day one.