Remote MCP Server Connections

Remote connections allow you to connect to Model Context Protocol (MCP) servers hosted on remote machines, cloud infrastructure, or different networks. This enables distributed architectures where MCP servers can be deployed separately from client applications.

Understanding Remote MCP Architecture

Remote MCP servers enable scalable, distributed AI systems by allowing:

Centralized server deployment - Host specialized MCP servers on dedicated infrastructure
Cross-network access - Connect to servers across different networks and cloud providers
Load distribution - Distribute processing across multiple server instances
Shared resources - Multiple clients can access the same MCP server capabilities

For comprehensive information about the MCP specification and architecture, visit the official MCP documentation.

Transport Protocols

Pylee supports two transport protocols for remote MCP server connections:

Streamable HTTP (Recommended)

The Streamable HTTP transport uses modern HTTP streaming capabilities for efficient communication with remote MCP servers. This is the recommended protocol for most use cases. Transport Type: streamable URL Format:

https://api.example.com/v1/mcp
http://localhost:3000/mcp

Key Features:

Efficient HTTP streaming for real-time communication
Built-in error handling and retry mechanisms
Support for bidirectional communication
Compatible with standard HTTP infrastructure
Automatic connection management

Advantages:

Modern streaming capabilities
Lower latency than traditional request-response
Firewall and proxy friendly
Built-in HTTPS security support
Excellent performance for high-frequency operations

Best for:

Production deployments
Real-time applications
High-performance scenarios
Modern cloud infrastructure
Client applications with intermittent connectivity needs

WebSocket Protocol

Provides persistent, bidirectional communication channels for real-time interaction. URL Format:

ws://hostname:port/mcp
wss://hostname:port/mcp

Advantages:

Real-time bidirectional communication
Lower latency for frequent operations
Persistent connection reduces overhead
Native browser support

Disadvantages:

More complex connection management
May require special network configuration
Connection state management complexity

Best for:

Interactive applications requiring immediate responses
High-frequency tool invocation scenarios
Real-time collaborative environments
Applications needing bidirectional data flow

Server-Sent Events (SSE)

Uses Server-Sent Events for server-to-client streaming communication. URL Format:

http://hostname:port/mcp/events
https://hostname:port/mcp/events

Advantages:

Real-time server-to-client updates
Automatic reconnection handling
HTTP-based (firewall friendly)
Built-in browser support

Disadvantages:

Unidirectional (server to client only)
Limited browser connection limits
May require additional endpoint for client-to-server requests

Best for:

Live monitoring and status updates
Progress tracking for long-running operations
Event-driven architectures
Applications requiring server push notifications

Configuring Remote Connections in Pylee

Using the Pylee Configuration Interface

Navigate to your server’s configuration page and select Remote Configuration to set up remote MCP connections:

Go to Configuration

/{organization}/server/{server}/configuration/remotes

Add Remote Connection
- Click “Add Remote” to create a new remote connection
- Configure the transport type and endpoint URL
- Set up authentication headers if required

Remote Configuration Options

Basic Configuration

Transport Type: Choose between streamable (recommended) or sse (deprecated) URL: The endpoint URL for your remote MCP server

https://api.example.com/v1/mcp

Authentication Headers

Configure HTTP headers for authentication and custom requirements: Common Authentication Patterns:

{
  "name": "Authorization",
  "value": "Bearer your-api-token",
  "description": "API authentication token",
  "is_required": true,
  "is_secret": true
}

{
  "name": "X-API-Key",
  "value": "your-api-key",
  "description": "Service API key",
  "is_required": true,
  "is_secret": true
}

Header Configuration Fields

Name: The HTTP header name (e.g., “Authorization”, “X-API-Key”)
Value: The header value (tokens, keys, etc.)
Description: Optional description of the header’s purpose
Required: Mark if this header is mandatory for the connection
Secret: Mark if this header contains sensitive information

Variables in Remote Configuration

Remote configuration supports dynamic variables using bracket notation ({variable_name}) to avoid hardcoding sensitive information. Variables are resolved at runtime through a hierarchical lookup system. Variable Resolution Order:

Organization variables or secrets - Global settings for your organization
Registry variables or secrets - Shared configuration across the registry
User prompt - Interactive prompt when no value is found for required variables

Example with Variables:

{
  "name": "Authorization",
  "value": "Bearer {api_token}",
  "description": "Dynamic API token from variables",
  "is_required": true,
  "is_secret": true
}

For comprehensive information about variables configuration, see the Variables Configuration Guide.

Example Configurations

Production API with Authentication

{
  "transport_type": "streamable",
  "url": "https://mcp-api.yourcompany.com/v1/mcp",
  "headers": [
    {
      "name": "Authorization",
      "value": "Bearer prod_token_xyz123",
      "description": "Production API authentication",
      "is_required": true,
      "is_secret": true
    },
    {
      "name": "X-Client-Version",
      "value": "1.0.0",
      "description": "Client version identifier",
      "is_required": false,
      "is_secret": false
    }
  ]
}

Development Environment

{
  "transport_type": "streamable",
  "url": "http://localhost:3000/mcp",
  "headers": [
    {
      "name": "X-Environment",
      "value": "development",
      "description": "Environment identifier",
      "is_required": false,
      "is_secret": false
    }
  ]
}

Legacy Server Configuration

For reference, here’s how to configure an MCP server to accept remote connections:

Node.js Streamable Server

import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { StreamableTransport } from '@modelcontextprotocol/sdk/server/streamable.js';
import express from 'express';

const app = express();
const server = new Server(
  {
    name: 'remote-mcp-server',
    version: '1.0.0',
  },
  {
    capabilities: {
      resources: {},
      tools: {},
    },
  }
);

// Configure HTTP transport
const transport = new HTTPServerTransport({
  port: 8080,
  host: '0.0.0.0',
  cors: {
    origin: ['https://your-client-domain.com'],
    credentials: true
  }
});

await server.connect(transport);
console.log('MCP server listening on http://0.0.0.0:8080');

import { Server } from '@modelcontextprotocol/sdk/server/index.js';
import { WebSocketServerTransport } from '@modelcontextprotocol/sdk/server/websocket.js';

const server = new Server(
  {
    name: 'websocket-mcp-server',
    version: '1.0.0',
  },
  {
    capabilities: {
      resources: {},
      tools: {},
    },
  }
);

const transport = new WebSocketServerTransport({
  port: 8080,
  host: '0.0.0.0',
  path: '/mcp',
  // Optional authentication
  authenticate: async (request) => {
    const token = request.headers.authorization;
    return validateToken(token);
  }
});

await server.connect(transport);
console.log('WebSocket MCP server listening on ws://0.0.0.0:8080/mcp');

Client Configuration

Configure your client to connect to remote MCP servers:

import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { HTTPClientTransport } from '@modelcontextprotocol/sdk/client/http.js';

const client = new Client(
  {
    name: 'mcp-client',
    version: '1.0.0',
  },
  {
    capabilities: {},
  }
);

const transport = new HTTPClientTransport({
  baseUrl: 'https://your-mcp-server.com:8080',
  headers: {
    'Authorization': 'Bearer your-api-token',
    'Content-Type': 'application/json'
  },
  timeout: 30000
});

await client.connect(transport);

// Use the client
const resources = await client.listResources();
console.log('Available resources:', resources);

Authentication and Security

Authentication Methods

Implement proper authentication for remote MCP servers:

// Token-based authentication
const authenticateToken = async (token) => {
  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET);
    return { valid: true, user: decoded };
  } catch (error) {
    return { valid: false, error: error.message };
  }
};

// API key authentication
const authenticateApiKey = async (apiKey) => {
  const validKeys = await loadValidApiKeys();
  return validKeys.includes(apiKey);
};

// Custom authentication middleware
server.setAuthenticationHandler(async (request) => {
  const authHeader = request.headers.authorization;
  
  if (!authHeader) {
    throw new Error('Authentication required');
  }
  
  if (authHeader.startsWith('Bearer ')) {
    const token = authHeader.substring(7);
    const result = await authenticateToken(token);
    if (!result.valid) {
      throw new Error('Invalid token');
    }
    return result.user;
  }
  
  if (authHeader.startsWith('ApiKey ')) {
    const apiKey = authHeader.substring(7);
    const isValid = await authenticateApiKey(apiKey);
    if (!isValid) {
      throw new Error('Invalid API key');
    }
    return { apiKey };
  }
  
  throw new Error('Unsupported authentication method');
});

Security Best Practices

Always implement these security measures for remote MCP servers:

Use HTTPS/WSS - Always encrypt connections in production
Implement authentication - Require valid credentials for all requests
Validate inputs - Sanitize and validate all tool parameters and resource requests
Rate limiting - Implement request rate limiting to prevent abuse
CORS configuration - Configure Cross-Origin Resource Sharing appropriately
Audit logging - Log all access attempts and operations
Regular updates - Keep MCP SDK and dependencies updated

// Security middleware example
import rateLimit from 'express-rate-limit';
import helmet from 'helmet';

// Rate limiting
const limiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // limit each IP to 100 requests per windowMs
  message: 'Too many requests from this IP'
});

// Security headers
app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      connectSrc: ["'self'", "wss:"]
    }
  }
}));

app.use('/mcp', limiter);

// Input validation
server.setRequestHandler(CallToolRequestSchema, async (request) => {
  const { name, arguments: args } = request.params;
  
  // Validate tool name
  if (!/^[a-zA-Z0-9_-]+$/.test(name)) {
    throw new Error('Invalid tool name format');
  }
  
  // Validate arguments
  const validated = await validateToolArguments(name, args);
  if (!validated.valid) {
    throw new Error(`Invalid arguments: ${validated.error}`);
  }
  
  return await executeTool(name, validated.args);
});

Load Balancing and Scaling

Multiple Server Instances

Deploy multiple MCP server instances for high availability:

// Load balancer configuration example
const servers = [
  'https://mcp-server-1.com:8080',
  'https://mcp-server-2.com:8080',
  'https://mcp-server-3.com:8080'
];

class LoadBalancedMCPClient {
  constructor(serverUrls) {
    this.servers = serverUrls;
    this.currentIndex = 0;
    this.clients = new Map();
  }
  
  async getClient() {
    const serverUrl = this.servers[this.currentIndex];
    
    if (!this.clients.has(serverUrl)) {
      const client = new Client({
        name: 'load-balanced-client',
        version: '1.0.0'
      }, { capabilities: {} });
      
      const transport = new HTTPClientTransport({
        baseUrl: serverUrl,
        timeout: 10000
      });
      
      await client.connect(transport);
      this.clients.set(serverUrl, client);
    }
    
    // Round-robin selection
    this.currentIndex = (this.currentIndex + 1) % this.servers.length;
    
    return this.clients.get(serverUrl);
  }
  
  async callTool(name, arguments) {
    const maxRetries = 3;
    let lastError;
    
    for (let i = 0; i < maxRetries; i++) {
      try {
        const client = await this.getClient();
        return await client.callTool({ name, arguments });
      } catch (error) {
        lastError = error;
        console.warn(`Server failed, trying next: ${error.message}`);
      }
    }
    
    throw new Error(`All servers failed: ${lastError.message}`);
  }
}

Docker Deployment

Deploy MCP servers using Docker for scalability:

# Dockerfile for MCP server
FROM node:18-slim

WORKDIR /app

# Install dependencies
COPY package*.json ./
RUN npm ci --only=production

# Copy application code
COPY . .

# Create non-root user
RUN useradd -m -u 1001 mcpuser
RUN chown -R mcpuser:mcpuser /app
USER mcpuser

# Expose port
EXPOSE 8080

# Health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

# Start server
CMD ["node", "dist/server.js"]

# docker-compose.yml for multiple instances
version: '3.8'
services:
  mcp-server-1:
    build: .
    ports:
      - "8081:8080"
    environment:
      - NODE_ENV=production
      - SERVER_ID=server-1
    restart: unless-stopped
    
  mcp-server-2:
    build: .
    ports:
      - "8082:8080"
    environment:
      - NODE_ENV=production
      - SERVER_ID=server-2
    restart: unless-stopped
    
  nginx:
    image: nginx:alpine
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf
      - ./ssl:/etc/nginx/ssl
    depends_on:
      - mcp-server-1
      - mcp-server-2
    restart: unless-stopped

Monitoring and Observability

Health Checks

Implement health monitoring for remote MCP servers:

// Health check endpoint
server.addHealthCheck('/health', async () => {
  const checks = {
    server: 'healthy',
    database: await checkDatabase(),
    externalServices: await checkExternalServices(),
    memory: process.memoryUsage(),
    uptime: process.uptime()
  };
  
  const allHealthy = Object.values(checks)
    .filter(v => typeof v === 'string')
    .every(status => status === 'healthy');
  
  return {
    status: allHealthy ? 'healthy' : 'unhealthy',
    timestamp: new Date().toISOString(),
    checks
  };
});

// Readiness check for load balancers
server.addHealthCheck('/ready', async () => {
  const isReady = await checkServerReadiness();
  return {
    status: isReady ? 'ready' : 'not-ready',
    timestamp: new Date().toISOString()
  };
});

Metrics Collection

Track server performance and usage:

// Prometheus metrics example
import prometheus from 'prom-client';

const requestCounter = new prometheus.Counter({
  name: 'mcp_requests_total',
  help: 'Total number of MCP requests',
  labelNames: ['method', 'status']
});

const requestDuration = new prometheus.Histogram({
  name: 'mcp_request_duration_seconds',
  help: 'Duration of MCP requests',
  labelNames: ['method']
});

const activeConnections = new prometheus.Gauge({
  name: 'mcp_active_connections',
  help: 'Number of active MCP connections'
});

// Instrument request handling
server.onRequest(async (request, response) => {
  const startTime = Date.now();
  const method = request.method;
  
  try {
    const result = await handleRequest(request);
    requestCounter.inc({ method, status: 'success' });
    return result;
  } catch (error) {
    requestCounter.inc({ method, status: 'error' });
    throw error;
  } finally {
    const duration = (Date.now() - startTime) / 1000;
    requestDuration.observe({ method }, duration);
  }
});

// Expose metrics endpoint
server.addRoute('/metrics', async (req, res) => {
  res.set('Content-Type', prometheus.register.contentType);
  res.end(await prometheus.register.metrics());
});

Security Best Practices

Authentication

Always use HTTPS for production deployments
Implement proper API key or token-based authentication
Mark sensitive headers as “secret” in the configuration
Rotate authentication credentials regularly

Network Security

Use secure transport protocols (HTTPS)
Configure proper CORS policies on your MCP servers
Implement rate limiting and request throttling
Monitor and log connection attempts

Troubleshooting Remote Connections

Configuration Issues

Remote endpoint not accessible:

Verify the URL is correct and reachable
Check network connectivity and firewall rules
Ensure the remote server is running and accepting connections

Authentication failures:

Verify API keys or tokens are correct and not expired
Check that required headers are properly configured
Ensure sensitive headers are marked as “secret”

Transport protocol issues:

Use streamable transport for new implementations
Migrate from sse to streamable for better performance
Verify the remote server supports the selected transport type

Debugging Steps

Test connectivity:

curl -I https://your-mcp-endpoint.com/v1/mcp

Verify authentication:

curl -H "Authorization: Bearer your-token" https://your-mcp-endpoint.com/v1/mcp

Check server logs for connection attempts and errors
Monitor network traffic to identify connection issues

Common Issues

Connection Timeouts

Check network connectivity between client and server
Verify firewall rules allow traffic on required ports
Increase client timeout settings if operations are slow
Monitor server resource usage and performance

Authentication Failures

Verify API keys or tokens are valid and not expired
Check authentication headers are properly formatted
Ensure server authentication configuration matches client
Review server logs for specific authentication errors

Protocol Errors

Validate MCP message format compliance using MCP Inspector
Check JSON-RPC 2.0 format adherence
Verify required fields are present in all messages
Test with minimal client to isolate issues

Performance Issues

Monitor server resource usage (CPU, memory, network)
Check for database connection pooling bottlenecks
Implement caching for frequently accessed resources
Consider using connection pooling on the client side

Debugging Tools

Use these tools to debug remote MCP connections:

# Test server connectivity
curl -v https://your-mcp-server.com:8080/health

# WebSocket connection testing
wscat -c wss://your-mcp-server.com:8080/mcp

# MCP protocol testing
npx @modelcontextprotocol/inspector http https://your-mcp-server.com:8080/mcp

# Load testing
npx autocannon -c 10 -d 30 https://your-mcp-server.com:8080/mcp

Protocol Selection Guide

Choose the right protocol based on your requirements:

Use Case	Recommended Protocol	Reason
Web APIs	HTTP/HTTPS	Standard, cacheable, firewall-friendly
Real-time Apps	WebSocket	Bidirectional, low-latency communication
Live Dashboards	SSE	Server push, automatic reconnection
Mobile Apps	HTTP/HTTPS	Better battery life, intermittent connectivity
High-frequency Tools	WebSocket	Persistent connection, lower overhead
Enterprise Integration	HTTP/HTTPS	Security policies, monitoring tools
Microservices	HTTP/HTTPS	Service mesh compatibility, load balancing

Deployment Patterns

Cloud Deployment

Common patterns for deploying remote MCP servers:

Container orchestration - Use Kubernetes or Docker Swarm for scaling
Serverless functions - Deploy as AWS Lambda, Azure Functions, or Google Cloud Functions
API Gateway integration - Use cloud API gateways for routing and authentication
CDN deployment - Cache resources using content delivery networks
Multi-region deployment - Deploy servers across regions for global access

Edge Computing

Deploy MCP servers closer to users:

// Edge-optimized MCP server
const edgeServer = new Server({
  name: 'edge-mcp-server',
  version: '1.0.0'
}, {
  capabilities: {
    resources: {},
    tools: {},
    // Enable caching for edge deployment
    caching: {
      enabled: true,
      ttl: 300,
      regions: ['us-east-1', 'eu-west-1', 'ap-southeast-1']
    }
  }
});

// Implement geo-aware resource routing
server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
  const clientRegion = request.headers['cf-ipcountry'] || 'US';
  const nearestCache = await findNearestCache(clientRegion);
  
  return await nearestCache.getResource(request.params.uri);
});

Next Steps

Once you have remote MCP server connections working:

Set up local MCP connections for development
Learn about MCP server configuration best practices
Explore the MCP specification in detail
Browse community MCP servers for examples
Study MCP security guidelines for production deployment

Migration from SSE to Streamable

If you’re currently using SSE transport, consider migrating to Streamable HTTP:

Migration Steps

Update transport type from sse to streamable in your remote configuration
Verify endpoint compatibility with Streamable HTTP protocol
Test the connection thoroughly in a development environment
Update monitoring and logging to account for the new transport
Deploy gradually using canary or blue-green deployment strategies

Benefits of Migration

Improved performance and reliability
Better error handling and recovery
Enhanced streaming capabilities
Future-proof protocol choice

Resources and Support

For additional help with remote MCP connections:

Get Started

Using Pylee

Understanding Pylee

MCP Servers

Support

​Remote MCP Server Connections

​Understanding Remote MCP Architecture

​Transport Protocols

​Streamable HTTP (Recommended)

​WebSocket Protocol

​Server-Sent Events (SSE)

​Configuring Remote Connections in Pylee

​Using the Pylee Configuration Interface

​Remote Configuration Options

​Basic Configuration

​Authentication Headers

​Header Configuration Fields

​Variables in Remote Configuration

​Example Configurations

​Production API with Authentication

​Development Environment

​Legacy Server Configuration

​Client Configuration

​Authentication and Security

​Authentication Methods

​Security Best Practices

​Load Balancing and Scaling

​Multiple Server Instances

​Docker Deployment

​Monitoring and Observability

​Health Checks

​Metrics Collection

​Security Best Practices

​Authentication

​Network Security

​Troubleshooting Remote Connections

​Configuration Issues

​Debugging Steps

​Common Issues

​Debugging Tools

​Protocol Selection Guide

​Deployment Patterns

​Cloud Deployment

​Edge Computing

​Next Steps

​Migration from SSE to Streamable

​Migration Steps

​Benefits of Migration

​Resources and Support

Remote MCP Server Connections

Understanding Remote MCP Architecture

Transport Protocols

Streamable HTTP (Recommended)

WebSocket Protocol

Server-Sent Events (SSE)

Configuring Remote Connections in Pylee

Using the Pylee Configuration Interface

Remote Configuration Options

Basic Configuration

Authentication Headers

Header Configuration Fields

Variables in Remote Configuration

Example Configurations

Production API with Authentication

Development Environment

Legacy Server Configuration

Client Configuration

Authentication and Security

Authentication Methods

Security Best Practices

Load Balancing and Scaling

Multiple Server Instances

Docker Deployment

Monitoring and Observability

Health Checks

Metrics Collection

Security Best Practices

Authentication

Network Security

Troubleshooting Remote Connections

Configuration Issues

Debugging Steps

Common Issues

Debugging Tools

Protocol Selection Guide

Deployment Patterns

Cloud Deployment

Edge Computing

Next Steps

Migration from SSE to Streamable

Migration Steps

Benefits of Migration

Resources and Support