API Reference

fetch(input, init)

Drop-in replacement for the global fetch.

• Accepts Headers, array pairs, or plain object for init.headers
• Body supports: string, URLSearchParams, FormData, and Blob
• Returns a spec-compliant Response with text(), json(), arrayBuffer(), blob(), bytes(), formData(), clone(), a body stream, and headers
• formData() parses application/x-www-form-urlencoded bodies only; other types, including multipart/form-data, reject with a TypeError
• init.priority ('high', 'low' or 'auto') sets the network priority of plain, streamed, worklet and prefetch requests. On Android it sets the Cronet request priority, which orders requests waiting for a connection. On iOS it sets URLSessionTask.priority (iOS 16+ for non-streamed requests), which URLSession treats as a hint. 'auto' keeps the default

import { fetch } from 'react-native-nitro-fetch';

const res = await fetch('https://jsonplaceholder.typicode.com/todos/1');
const data = await res.json();

nitroFetchOnWorklet(input, init, mapWorklet, options?)

Runs the network request and then invokes mapWorklet on a worklet runtime, keeping the JS thread free for UI work.

• mapWorklet(payload) receives { url, status, statusText, ok, redirected, headers, bodyBytes?, bodyString? }
• options.preferBytes (default false) controls whether bodyBytes or bodyString is sent to the mapper

import { nitroFetchOnWorklet } from 'react-native-nitro-fetch';

const map = (payload: { bodyString?: string }) => {
  'worklet';
  return JSON.parse(payload.bodyString ?? '{}');
};

const data = await nitroFetchOnWorklet(
  'https://httpbin.org/get',
  undefined,
  map,
  { preferBytes: false }
);

tip

See the Worklets guide for setup instructions.

prefetch(input, init)

Starts a background request in native when possible. Requires a prefetchKey provided either via headers: { prefetchKey } or init.prefetchKey.

Later, call fetch(url, { headers: { prefetchKey } }) to consume a fresh or pending prefetched result. On success, the response will include header nitroPrefetched: true.

prefetchOnAppStart(input, { prefetchKey })

Enqueues a request to be prefetched at the next app start by writing into native storage.

note

Enqueued requests are stored in native storage and automatically executed on the next app start on both platforms.

removeFromAutoPrefetch / removeAllFromAutoprefetch

Utilities to manage the auto-prefetch queue.

Types

NitroRequest

{
  url: string;
  method?: string;
  headers?: { key: string; value: string }[];
  bodyString?: string;
  bodyBytes?: ArrayBuffer;
  timeoutMs?: number;
  followRedirects?: boolean;
}

NitroResponse

{
  url: string;
  status: number;
  statusText: string;
  ok: boolean;
  redirected: boolean;
  headers: { key: string; value: string }[];
  bodyString?: string;
  bodyBytes?: ArrayBuffer;
}