Architecture

Understanding how PlexMCP Cloud works.

Overview

PlexMCP is a managed gateway for Model Context Protocol (MCP) servers. It sits between your AI agents and your MCP servers, providing authentication, routing, monitoring, and management.

┌─────────────────────────────────────────────────────────────────┐
│                        Your AI Agents                           │
│         (Claude Desktop, Custom Apps, Integrations)             │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼ API Requests
┌─────────────────────────────────────────────────────────────────┐
│                      PlexMCP Cloud                              │
│  ┌───────────────┐  ┌───────────────┐  ┌───────────────┐       │
│  │ Authentication │  │  Rate Limiting │  │   Analytics   │       │
│  │   & Routing   │  │   & Quotas    │  │  & Monitoring │       │
│  └───────────────┘  └───────────────┘  └───────────────┘       │
│                                                                  │
│  ┌───────────────────────────────────────────────────────────┐  │
│  │                     API Gateway                            │  │
│  │  • Load Balancing     • Health Checks    • Failover       │  │
│  └───────────────────────────────────────────────────────────┘  │
└─────────────────────────────────────────────────────────────────┘
                              │
                              ▼ MCP Protocol
┌─────────────────────────────────────────────────────────────────┐
│                       Your MCP Servers                          │
│   [Weather MCP]    [Database MCP]    [Custom Tools MCP]        │
└─────────────────────────────────────────────────────────────────┘

Components

API Gateway

The core routing layer:

• Receives API requests
• Authenticates using API keys
• Routes to appropriate MCPs
• Handles responses and errors

Authentication Service

Manages access control:

• API key validation
• Permission checking
• Rate limit enforcement
• Usage tracking

MCP Registry

Stores MCP configurations:

• Endpoint URLs
• Authentication details
• Health status
• Tool/resource metadata

Health Monitor

Ensures MCP availability:

• Regular health checks (60s interval)
• Status tracking
• Alerting (Pro+ plans)
• Automatic failover

Analytics Engine

Collects and processes usage data:

• Request counts
• Latency metrics
• Error rates
• Cost tracking

Request Flow

1. Authentication

Client Request
      │
      ▼
┌─────────────────┐
│ API Key Check   │──▶ Invalid? Return 401
└─────────────────┘
      │
      ▼ Valid

2. Authorization

┌─────────────────┐
│ Permission Check │──▶ No Access? Return 403
└─────────────────┘
      │
      ▼ Authorized

3. Rate Limiting

┌─────────────────┐
│ Rate Limit Check │──▶ Exceeded? Return 429
└─────────────────┘
      │
      ▼ Within Limits

4. Routing

┌─────────────────┐
│ Route to MCP    │──▶ MCP Unhealthy? Return 502
└─────────────────┘
      │
      ▼ Connected

5. Response

┌─────────────────┐
│ Return Response │──▶ Client
└─────────────────┘

Data Storage

What We Store

Data Type	Storage	Purpose
Organization info	Database	Configuration
MCP configs	Database	Routing
API keys (hashed)	Database	Authentication
Usage metrics	Time-series DB	Analytics
Audit logs	Append-only log	Compliance

What We Don't Store

• Full API key secrets (only hashes)
• MCP request/response content
• Tool arguments or results
• Any PII from MCP calls

Regional Infrastructure

PlexMCP runs on a global edge network:

Region	Location	Purpose
US-East	Virginia	Primary
US-West	California	Low latency
EU	Frankfurt	GDPR compliance
APAC	Singapore	Asia-Pacific

Requests are routed to the nearest healthy region.

High Availability

Uptime Guarantee

• Free: Best effort
• Pro: 99.9% SLA
• Team: 99.9% SLA
• Enterprise: Up to 99.99%

Redundancy

• Multiple availability zones
• Automatic failover
• Database replication
• CDN for static assets

Disaster Recovery

• Daily backups
• Point-in-time recovery
• Cross-region replication
• 4-hour RTO (Enterprise)

Security

Network Security

• All traffic encrypted (TLS 1.3)
• DDoS protection
• WAF (Web Application Firewall)
• IP allowlisting (Enterprise)

Application Security

• API key hashing (Argon2)
• Rate limiting
• Input validation
• Output sanitization

Compliance

• SOC 2 Type II (in progress)
• GDPR compliant
• Data Processing Agreement available
• Regular security audits

Integration Points

Inbound

• REST API (api.plexmcp.com)
• MCP Client SDK
• Claude Desktop integration

Outbound

• HTTP/HTTPS to your MCPs
• Webhooks for events
• Analytics exports

Scaling

PlexMCP automatically scales based on demand:

Metric	Scaling Behavior
Request volume	Auto-scale gateway
MCP count	No limits (Team+)
Team size	No limits (Team+)
Storage	Auto-expand

Self-Hosting

For those who need to run PlexMCP on their own infrastructure, see our open source documentation.

Self-hosted features:

• Full control over data
• Custom deployment options
• No usage limits
• Community support