Browser → server: generated data-access client, not `fetch`
**Scope: browser → server** (client-to-server). Browser or mobile app calling your own `/api/...` — not server-to-vendor calls, not server-to-server between your domains. Hand-written fetch to your API — changes fail in the browser, not at compile time.
Every domain with a backend produces a frontend data-access client (OpenAPI / tRPC / GraphQL codegen). UI and feature code import that client — they do not write fetch('/api/...') by hand. Server-to-vendor calls use a dedicated integration client. Server-to-internal domain calls use exported NestJS services, not HTTP between your own modules.
// frontend component — calling your own backend, not an external vendorconst res = await fetch(`/api/sites/${id}`);const data = await res.json() as any;// what fields? who knows. backend change? runtime errors.
Good
ts
// libs/sites-management/data-access/src/lib/client.ts// generated from OpenAPI / tRPCexport const sitesClient = createClient<SitesAPI>();// in a consumerconst site = await sitesClient.sites.get({ id });// site is fully typed. backend change? immediate compile error.
