MCP Pay Overview

MCP Pay is SolvaPay's monetization layer for MCP (Model Context Protocol) servers. It enables MCP server operators to create paywalled proxy endpoints for their tools, allowing them to charge users based on subscription plans while handling authentication, authorization, and usage tracking automatically.

How It Works

MCP Pay acts as a reverse proxy that sits between MCP clients (AI agents, IDE integrations, etc.) and your origin MCP server. When users connect through the proxy URL instead of directly to your server, SolvaPay handles:

• Authentication - Full OAuth 2.0 server with Google and GitHub sign-in
• Authorization - Checks if the user's subscription plan grants access to the requested tool
• Usage Tracking - Records tool invocations and enforces quota limits
• Billing - Manages subscriptions and payments (Stripe supported)
• Dynamic Client Registration - MCP clients can auto-register as OAuth clients

┌─────────────┐     ┌─────────────────┐     ┌──────────────────┐
│  MCP Client │────▶│  SolvaPay Proxy │────▶│  Origin MCP      │
│  (AI Agent) │     │  (mcpProxyUrl)  │     │  Server          │
└─────────────┘     └─────────────────┘     └──────────────────┘
                           │
                    ┌──────┴──────┐
                    │ • Auth      │
                    │ • Plan Check│
                    │ • Quotas    │
                    │ • Tracking  │
                    └─────────────┘

Key Concepts

MCP Server (in SolvaPay)

An MCP Server record in SolvaPay represents your monetization configuration for an origin MCP server. It includes:

Field	Description
Name	Display name for your MCP server
Origin URL	The actual MCP server endpoint (e.g., https://mcp.example.com/mcp)
API Key	Optional credential for authenticating with the origin server
Proxy URL	Auto-generated URL that users connect to (provided after setup)
Default Plan	The free/signup plan automatically assigned to new users
Tools	List of discovered tools with their plan assignments

Tools and Plan Assignment

Each tool from your MCP server can be configured with:

• Plan Access - Which subscription plans can access this tool (multiple plans supported)
• No Plan - Tool is unprotected and not tracked (useful for free utility tools)

The default plan (typically a free tier) is always included for protected tools unless "No plan" is selected.

Virtual Tools

SolvaPay automatically injects these platform tools into every MCP server:

Tool	Description
get_user_info	Returns current user's subscription status
upgrade_plan	Returns available plans and checkout URLs
manage_subscription	Returns URL to the customer billing portal

Virtual tools are always free and not usage-tracked. They enable AI agents to help users manage their subscriptions.

MCP Pay vs SDK Integration

For a concise comparison of MCP Pay and SDK integration, see the Getting Started overview.

Request Flow

When a user calls a tool through the proxy:

1. Authentication - SolvaPay validates the user's OAuth access token
2. Authorization - Checks if their subscription plan includes access to the requested tool
3. Quota Check - Ensures they haven't exceeded their usage limits
4. Forwarding - If authorized, the request is forwarded to your origin MCP server
5. Tracking - Usage is recorded against their subscription

Tools marked as "No plan" skip authorization and tracking, allowing free access.

Next Steps

• Quick Start - Set up your first monetized MCP server
• Authentication - Learn about OAuth and client connections
• Hosted Pages - Configure checkout and customer portal