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MCP Billing Gateway

Source: mcp.so submission #3281 (July 23, 2026) · GitHub: sapph1re/mcp-billing-gateway-sdk

What It Does

Reverse proxy that adds Stripe fiat billing AND x402 crypto micropayments to any MCP server without touching upstream server code. Operators register their server, set per-call prices, and issue API keys. Clients authenticate with an API key; each tool call routes through the gateway for metering, payment verification, and transparent proxying.

Key capabilities: - Stripe fiat billing + x402 crypto micropayments in one gateway - Zero upstream server code changes required - API key management and per-call metering - Transparent proxying to upstream MCP server

Relevance to Operators

Essential for MCP server operators who want to monetize: - Wrap any MCP server with billing in minutes - Offer both fiat (Stripe) and crypto (x402) payment options - Track per-client usage and enforce rate limits - No need to build billing logic into your server code

Rating: ★★ — Early stage (1 GitHub star, created April 2026). Addresses a growing need as the MCP ecosystem matures toward monetization. Part of the same developer's "sapph1re" suite alongside Feedback Synthesis MCP.

Quick Integration

Transport: Reverse proxy (sits between client and upstream MCP server)
Auth: API key per client
Pricing: Free to deploy (gateway is open source); Stripe fees apply, x402 gas fees apply 

# Deploy the gateway
git clone https://github.com/sapph1re/mcp-billing-gateway-sdk
cd mcp-billing-gateway-sdk
npm install
npm run build

# Configure your upstream MCP server
export UPSTREAM_URL="https://your-server.com/mcp"
export STRIPE_SECRET_KEY="sk_live_..."
npm start

Use Cases

  1. SaaS MCP Server: Add Stripe subscriptions to your hosted MCP server
  2. Pay-per-call APIs: Charge per tool invocation via x402 micropayments
  3. Freemium Gate: Offer free tier to first N calls, then require payment

Caveats

  • 1 GitHub star, very early stage
  • Adds latency overhead (one proxy hop)
  • Requires Stripe account for fiat billing
  • x402 payment ecosystem still nascent