Stateful API6 min read2026-04-14

How to Turn JSON into a Mock CRUD API in 60 Seconds

Convert any JSON payload into a fully functional REST API with GET, POST, PUT, and DELETE endpoints instantly. No sign-up, no backend code, no deployment. Self-cleaning endpoints powered by edge infrastructure.

The Problem with Mock APIs

Every frontend developer has been here: you're building a React dashboard, a mobile app, or prototyping a new feature. You need a backend. But the real API isn't ready yet, or you just need something quick and disposable.

Your options are usually: - JSONPlaceholder — read-only, fixed data, can't POST/PUT/DELETE - Mock Service Worker — great, but requires setup and lives in your codebase - Spin up Express — overkill for a 30-minute prototype - Postman Mock — requires an account and configuration

What if you could just paste JSON and get a live CRUD API in under 60 seconds?

Step 1: Define Your Data

Start with any valid JSON array. This will become your initial database. Here's an example — a simple product catalog:

json

[
  {
    "id": 1,
    "name": "Wireless Headphones",
    "price": 79.99,
    "category": "electronics",
    "inStock": true
  },
  {
    "id": 2,
    "name": "Mechanical Keyboard",
    "price": 149.99,
    "category": "electronics",
    "inStock": true
  },
  {
    "id": 3,
    "name": "Standing Desk",
    "price": 599.99,
    "category": "furniture",
    "inStock": false
  }
]

Step 2: Paste into the Stateful API Tool

Open the Stateful API tool on Antimass Labs. Paste your JSON into the payload editor and hit Deploy. That's it.

You'll instantly receive a unique endpoint URL like:

https://antimasslabs.com/api/mock/abc123

This endpoint is now a fully stateful REST API backed by Redis on Cloudflare's edge network. It supports:

Method	Endpoint	Action
GET	`/api/mock/{id}`	Fetch all items or single item by payload key
POST	`/api/mock/{id}`	Add a new item to the collection
PUT	`/api/mock/{id}`	Update an existing item by key
DELETE	`/api/mock/{id}`	Remove an item from the collection

Step 3: Test with curl or fetch

Your API is live. Test it immediately:

bash

# GET all items
curl https://antimasslabs.com/api/mock/abc123

# POST a new item
curl -X POST https://antimasslabs.com/api/mock/abc123 \
  -H "Content-Type: application/json" \
  -d '{"id": 4, "name": "USB-C Hub", "price": 39.99, "category": "electronics", "inStock": true}'

# PUT (update) an item
curl -X PUT https://antimasslabs.com/api/mock/abc123 \
  -H "Content-Type: application/json" \
  -d '{"id": 2, "name": "Mechanical Keyboard", "price": 129.99, "category": "electronics", "inStock": true}'

# DELETE an item
curl -X DELETE https://antimasslabs.com/api/mock/abc123 \
  -H "Content-Type: application/json" \
  -d '{"id": 3}'

Using with React / Next.js

Here's how to use your mock API in a React component:

tsx

'use client';
import { useState, useEffect } from 'react';

const API_URL = 'https://antimasslabs.com/api/mock/abc123';

export default function ProductList() {
  const [products, setProducts] = useState([]);

  useEffect(() => {
    fetch(API_URL)
      .then(res => res.json())
      .then(data => setProducts(data.payload || []));
  }, []);

  const addProduct = async (product) => {
    await fetch(API_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(product),
    });
    // Refresh
    const res = await fetch(API_URL);
    const data = await res.json();
    setProducts(data.payload || []);
  };

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

Self-Cleaning Endpoints

Every mock endpoint created on Antimass Labs has a 24-hour TTL (time-to-live). After 24 hours, the endpoint and all its data are automatically purged from Redis.

This design is intentional: - No stale mock servers cluttering infrastructure - No accidental production usage — endpoints are clearly temporary - No cleanup required — create, test, forget - Privacy-first — your test data is automatically deleted

Need persistent endpoints? Keep the Stateful API tool open — creating a new deployment resets the TTL. For CI/CD pipelines, simply generate a fresh endpoint at the start of each test run.

Try the Stateful API →Open the tool and start using it — no signup required.

→

Antimass Labs