Frontend Prototyping Masterclass

Free Mock REST APIs for React Developers

Stop writing hardcoded mock JSON arrays in your React components. Connect directly to live, CORS-enabled endpoints with zero authentication.

Explore Product Catalog API → AI Next.js Handler Generator

1. TanStack Query (`useQuery`) with Products

Fetch and cache mock products with automatic loading and error states.

View API Docs

import { useQuery } from '@tanstack/react-query';

interface Product {
  id: string;
  title: string;
  price: number;
  category: string;
}

export function ProductList() {
  const { data: products, isLoading, error } = useQuery<Product[]>({
    queryKey: ['products'],
    queryFn: async () => {
      const res = await fetch('https://gen-endpoint.com/api/products');
      if (!res.ok) throw new Error('Network error');
      return res.json();
    },
  });

  if (isLoading) return <div>Loading products...</div>;
  if (error) return <div>Error loading catalog.</div>;

  return (
    <ul>
      {products?.map((p) => (
        <li key={p.id}>{p.title} - ${p.price}</li>
      ))}
    </ul>
  );
}

2. SWR Data Fetching with User Management

Simulate optimistic revalidation and profile lookups with `/api/users`.

View API Docs

import useSWR from 'swr';

const fetcher = (url: string) => fetch(url).then((r) => r.json());

export function UserProfile() {
  const { data, error, isLoading } = useSWR(
    'https://gen-endpoint.com/api/users',
    fetcher
  );

  if (isLoading) return <div>Loading users...</div>;
  if (error) return <div>Failed to load users.</div>;

  return (
    <div>
      <h3>Users ({data.users.length})</h3>
      {data.users.map((u: any) => (
        <p key={u.id}>{u.name} ({u.email})</p>
      ))}
    </div>
  );
}

3. Mock Login Mutation & Form Handling

Test login forms, JWT token storage, and feedback toasts using `/api/auth/login`.

View API Docs

async function handleLogin(email: string, pass: string) {
  const res = await fetch('https://gen-endpoint.com/api/auth/login', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ email, password: pass }),
  });

  const data = await res.json();
  if (res.ok) {
    localStorage.setItem('auth_token', data.token);
    alert(`Welcome back, ${data.user.name}!`);
  } else {
    alert(data.error || 'Login failed');
  }
}

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