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

1. Clone or download this project
2. 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