MCP REST API Tester

A TypeScript-based MCP server that enables testing of REST APIs through Cline. This tool allows you to test and interact with any REST API endpoints directly from your development environment.

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Installation

Installing via Smithery

To install REST API Tester for Claude Desktop automatically via Smithery:

npx -y @smithery/cli install dkmaker-mcp-rest-api --client claude

Installing Manually

1. Install the package globally:

npm install -g dkmaker-mcp-rest-api

2. Configure Cline Custom Instructions:

To ensure Cline understands how to effectively use this tool, add the following to your Cline custom instructions (Settings > Custom Instructions):

# REST API Testing Instructions

The `test_request` tool enables testing, debugging, and interacting with REST API endpoints. The tool provides comprehensive request/response information and handles authentication automatically.

## When to Use

- Testing specific API endpoints
- Debugging API responses
- Verifying API functionality
- Checking response times
- Validating request/response formats
- Testing local development servers
- Testing API sequences
- Verifying error handling

## Key Features

- Supports GET, POST, PUT, DELETE methods
- Handles authentication (Basic, Bearer, API Key)
- Normalizes endpoints automatically
- Provides detailed response information
- Configurable SSL verification and response limits

## Resources

The following resources provide detailed documentation:

- examples: Usage examples and common patterns
- response-format: Response structure and fields
- config: Configuration options and setup guide

Access these resources to understand usage, response formats, and configuration options.

## Important Notes

- Review API implementation for expected behavior
- Handle sensitive data appropriately
- Consider rate limits and API constraints
- Restart server after configuration changes

3. Add the server to your MCP configuration:

While these instructions are for Cline, the server should work with any MCP implementation. Configure based on your operating system:

Windows

⚠️ IMPORTANT: Due to a known issue with Windows path resolution (issue #40), you must use the full path instead of %APPDATA%.

Add to C:\Users\<YourUsername>\AppData\Roaming\Code\User\globalStorage\saoudrizwan.claude-dev\settings\cline_mcp_settings.json:

{
  "mcpServers": {
    "rest-api": {
      "command": "node",
      "args": [
        "C:/Users/<YourUsername>/AppData/Roaming/npm/node_modules/dkmaker-mcp-rest-api/build/index.js"
      ],
      "env": {
        "REST_BASE_URL": "https://api.example.com",
        // Basic Auth
        "AUTH_BASIC_USERNAME": "your-username",
        "AUTH_BASIC_PASSWORD": "your-password",
        // OR Bearer Token
        "AUTH_BEARER": "your-token",
        // OR API Key
        "AUTH_APIKEY_HEADER_NAME": "X-API-Key",
        "AUTH_APIKEY_VALUE": "your-api-key",
        // SSL Verification (enabled by default)
        "REST_ENABLE_SSL_VERIFY": "false", // Set to false to disable SSL verification for self-signed certificates
        // Response Size Limit (optional, defaults to 10000 bytes)
        "REST_RESPONSE_SIZE_LIMIT": "10000", // Maximum response size in bytes
        // Custom Headers (optional)
        "HEADER_X-API-Version": "2.0",
        "HEADER_Custom-Client": "my-client",
        "HEADER_Accept": "application/json"
      }
    }
  }
}

macOS

Add to ~/Library/Application Support/Code/User/globalStorage/saoudrizwan.claude-dev/settings/cline_mcp_settings.json:

{
  "mcpServers": {
    "rest-api": {
      "command": "npx",
      "args": [
        "-y",
        "dkmaker-mcp-rest-api"
      ],
      "env": {
        "REST_BASE_URL": "https://api.example.com",
        // Basic Auth
        "AUTH_BASIC_USERNAME": "your-username",
        "AUTH_BASIC_PASSWORD": "your-password",
        // OR Bearer Token
        "AUTH_BEARER": "your-token",
        // OR API Key
        "AUTH_APIKEY_HEADER_NAME": "X-API-Key",
        "AUTH_APIKEY_VALUE": "your-api-key",
        // SSL Verification (enabled by default)
        "REST_ENABLE_SSL_VERIFY": "false", // Set to false to disable SSL verification for self-signed certificates
        // Custom Headers (optional)
        "HEADER_X-API-Version": "2.0",
        "HEADER_Custom-Client": "my-client",
        "HEADER_Accept": "application/json"
      }
    }
  }
}

Note: Replace the environment variables with your actual values. Only configure one authentication method at a time:

1. Basic Authentication (username/password)
2. Bearer Token (if Basic Auth is not configured)
3. API Key (if neither Basic Auth nor Bearer Token is configured)

Features

• Test REST API endpoints with different HTTP methods

• Support for GET, POST, PUT, and DELETE requests

• Detailed response information including status, headers, and body

• Custom Headers:

  • Global headers via HEADER_* environment variables
  • Case-insensitive prefix (HEADER_, header_, HeAdEr_)
  • Case preservation for header names
  • Priority-based application (per-request > auth > custom)

• Request body handling for POST/PUT methods

• Response Size Management:

  • Automatic response size limiting (default: 10KB/10000 bytes)
  • Configurable size limit via REST_RESPONSE_SIZE_LIMIT environment variable
  • Clear truncation metadata when responses exceed limit
  • Preserves response structure while only truncating body content

• SSL Certificate Verification:

  • Enabled by default for secure operation
  • Can be disabled for self-signed certificates or development environments
  • Control via REST_ENABLE_SSL_VERIFY environment variable

• Multiple authentication methods:

  • Basic Authentication (username/password)
  • Bearer Token Authentication
  • API Key Authentication (custom header)

Usage Examples

Once installed and configured, you can use the REST API Tester through Cline to test your API endpoints:

// Test a GET endpoint
use_mcp_tool('rest-api', 'test_request', {
  "method": "GET",
  "endpoint": "/users"
});

// Test a POST endpoint with body
use_mcp_tool('rest-api', 'test_request', {
  "method": "POST",
  "endpoint": "/users",
  "body": {
    "name": "John Doe",
    "email": "john@example.com"
  }
});

// Test with custom headers
use_mcp_tool('rest-api', 'test_request', {
  "method": "GET",
  "endpoint": "/products",
  "headers": {
    "Accept-Language": "en-US",
    "X-Custom-Header": "custom-value"
  }
});

Development

1. Clone the repository:

git clone https://github.com/zenturacp/mcp-rest-api.git
cd mcp-rest-api

2. Install dependencies:

npm install

3. Build the project:

npm run build

For development with auto-rebuild:

npm run watch

License

This project is licensed under the MIT License - see the LICENSE file for details.