JSON Convenience

Use the json option to send a serialized JSON request body without manual stringification or headers.

The json option serializes the request body and sets Content-Type.

import { api } from "@zap-studio/fetch";

await api.post("/api/users", UserSchema, {
  json: { name: "Ada" },
});

UserSchema still validates the response — the json value is only the outgoing request body and is not validated by the schema.

What It Sets

Providing json sets:

• body to JSON.stringify(json)
• Content-Type to application/json, when no content type is already set on headers

import { $fetch } from "@zap-studio/fetch";

const user = await $fetch("https://api.example.com/users", UserSchema, {
  method: "POST",
  json: { name: "Ada" },
});

Mutually Exclusive with body

json and native body cannot be used together — providing both throws a TypeError.

await $fetch("/api/upload", {
  method: "POST",
  body: formData, // use native `body` for FormData, Blob, ReadableStream, etc.
});

See Also

• Validated Fetch Mode — how the response schema and json interact.
• HTTP Method Helpers — api.post, api.put, and api.patch examples.
• Overview — package summary and quick start.