How to Quickly Mock REST APIs with json-server: A Step‑by‑Step Guide

In front‑end and back‑end development, communication often happens via web APIs using REST style and JSON structures. For example, a front‑end may request a list of articles with GET /post and receive JSON data.

When the back‑end cannot keep up with front‑end development speed, developers can mock the API by providing predefined JSON data.

json-server is a tool that serves a JSON file as a full‑featured REST API without writing any code. Install it globally: npm install -g json-server Create a db.json file, e.g.:

{
  "posts": [
    { "id": 1, "title": "测试 json-server", "author": "dys" }
  ]
}

Start the server: json-server db.json The console shows a greeting and the resources, e.g. http://localhost:3000/posts. Accessing that URL in a browser returns the posts array.

You can also retrieve a single item with GET http://localhost:3000/posts/1, or add a new item using a POST request. For example, sending the following JSON payload:

{
  "id": 2,
  "title": "测试 post",
  "author": "dys"
}

adds a new post, which then appears when you request http://localhost:3000/posts again.

The image below shows the POST request in a HTTP client.

json-server also offers many advanced features; see its official repository for more details.

Project homepage: https://github.com/typicode/json-server