JSONPlaceholder MCP Server

A modern Model Context Protocol (MCP) server built with FastMCP that provides access to the JSONPlaceholder API - a free fake REST API for testing and prototyping.

Features

This MCP server provides Resources, Tools, and Prompts for interacting with JSONPlaceholder:

🔧 Tools (Actions)

get_posts - Retrieve all posts or a specific post by ID
get_users - Retrieve all users or a specific user by ID
get_comments - Retrieve comments, optionally filtered by post ID
get_albums - Retrieve albums, optionally filtered by user ID
get_photos - Retrieve photos, optionally filtered by album ID
get_todos - Retrieve todos, optionally filtered by user ID
create_post - Create a new post (simulated)
search_posts - Search posts by title or body content

📄 Resources (Data Access)

posts://all - Get all posts as a resource
posts://{post_id} - Get a specific post as a resource
users://all - Get all users as a resource
users://{user_id} - Get a specific user as a resource

📝 Prompts (Templates)

analyze_post - Generate analysis prompt for a specific post
user_profile_summary - Create comprehensive user profile analysis

How to add it to cursor:

  "mcpServers": {
    "jsonplaceholder": {
      "command": "/Users/danielpopa/Projects/work/mcp-server/cursor_runner.sh",
      "args": []
    }
  }
}

Prerequisites

Python 3.10+
uv package manager

Installation

Clone or download this project
The project is already configured with uv. Simply run:

uv sync

Development & Testing

MCP Inspector (recommended for development):

uv run mcp dev server.py

This opens an interactive web interface to test all tools, resources, and prompts.

Direct server execution:

uv run python server.py

Test API connectivity:

uv run python test_server.py

Claude Desktop Integration

Install directly into Claude Desktop:

uv run mcp install server.py --name "JSONPlaceholder API"

Usage Examples

Once connected to an MCP client, you can:

Use Tools:

"Get all posts from JSONPlaceholder"
"Show me user details for user ID 1"
"Search for posts containing 'dolor'"
"Create a new post titled 'Test' with body 'Hello World' for user 1"

Access Resources:

The client can load posts://all to get all posts as context
Load users://5 to get user 5's details as background information

Use Prompts:

Use the "analyze_post" prompt with post ID 1 for detailed post analysis
Use "user_profile_summary" with user ID 2 for comprehensive user profiling

API Information

This server uses the JSONPlaceholder API (https://jsonplaceholder.typicode.com/), which provides:

100 posts
10 users
500 comments
100 albums
5000 photos
200 todos

No API key is required as it's completely free and public.

Architecture

Built with FastMCP, this server demonstrates modern MCP patterns:

Decorator-based setup - Clean, Pythonic code
Type hints - Better development experience
Async/await - Efficient HTTP requests
Resource management - Proper data exposure to LLMs
Prompt templates - Reusable interaction patterns
Development tools - Built-in testing and debugging

Development

The server uses:

FastMCP - Modern MCP server framework
httpx - Async HTTP client
Python 3.10+ - Modern Python features
uv - Fast Python package management