#API Client and Contracts

Vext pages do not need a generated API client for first-screen data. Use route handlers and res.render() for that.

#Primary Data Path

route handler -> app.services -> res.render(page, props)

This path keeps service calls server-side and produces SSR HTML with hydration data.

#Generated Artifacts

When frontend.apiClient is enabled, Vext can emit:

client-contract.json
api.generated.ts

These artifacts are useful for:

• external frontend adapters
• type probes
• client-side API calls after hydration
• documentation or tooling

#Public Entry

The frontend public entry exposes contract helpers:

import {
  createVextApiClient,
  createVextFetchAdapter,
} from "vextjs/frontend";

Use them when you need a typed client boundary. Do not add them to simple pages just to read first-screen data.

#Plain Fetch Is Fine

For small client interactions after hydration:

await fetch("/api/preferences", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify(payload),
});

Make sure client requests send the right Accept header so API calls are not treated as HTML navigation inside a SPA fallback scope.

#Boundary Rule

Generated client artifacts describe HTTP contracts. They do not make src/services/** browser-safe. Service modules remain server-only.