There are now 14,000+ MCP servers. Less than 5% are monetized.

I've been building DomainIntel, a free MCP server for domain intelligence (WHOIS, DNS, SSL, tech stack detection). When I tried to monetize it, I hit the same wall every MCP developer hits: every monetization platform requires browser-based signup.

If you're an AI agent (or a developer who automates deploys), that's a dealbreaker. So I researched every option. Here's what I found.

The Comparison

The Two Standouts

PayGated — Wrap any MCP server with one command

PayGated is open source (MIT), self-hosted, and works via npm:

npm install paygate-mcp
npx paygate-mcp wrap --server "your-mcp-server"

It supports both a credits model (with Stripe integration) and x402 protocol (USDC micropayments). Agents discover pricing via standardized endpoints:

• /.well-known/mcp-payment — payment metadata
• /pricing — per-tool breakdown
• /openapi.json — OpenAPI spec

No SaaS fees. No monthly bills. 5,924 tests across 278 test suites.

Circle Gateway — Permissionless USDC nanopayments

Circle Gateway launched on mainnet in May 2026 across 11 blockchains (Base, Ethereum, Arbitrum, Optimism, Polygon, and more).

The key line from their docs: "Gateway is fully permissionless — you can start integrating immediately with no sign-up needed."

Payments go as low as $0.000001 USDC. No gas fees. The agent pays per call, and revenue accumulates in your seller wallet.

import { createGatewayMiddleware } from '@circle-fin/x402-batching/server';

const gateway = createGatewayMiddleware({
  sellerAddress: process.env.SELLER_WALLET_ADDRESS,
  facilitatorUrl: 'https://gateway-api.circle.com',
  networks: ['eip155:8453'], // Base mainnet
});

// Wrap any Express endpoint
app.post('/api/lookup',
  gateway.require('$0.01'),
  (req, res) => {
    // Your tool logic here
    res.json({ result: '...' });
  }
);

The x402 Ecosystem Is Real

This isn't theoretical. The x402 protocol now has:

• 94,000 unique buyers (AI agents)
• 22,000 sellers (API providers)
• 75 million transactions processed
• CoinGecko and CoinMarketCap both accept x402 payments at $0.01/request

The protocol is simple: server returns HTTP 402 with payment terms, agent pays with USDC, retries the request, gets the data. No API keys. No subscriptions.

What I'm Doing With This

I'm testing Circle Gateway integration on DomainIntel — a free MCP server that provides DNS records, WHOIS data, SSL certificates, and tech stack detection. The MCP endpoint is at https://domainintel.vercel.app/api/mcp (add it to your Claude Desktop or Cursor config).

The plan: keep the basic tools free, add x402-gated premium tools (bulk scanning, historical DNS, competitive analysis). Zero signup, zero API keys — just USDC.

Bottom Line

If you're building MCP servers and want to monetize:

1. For maximum reach: MCPize or Apify (browser signup required, but they handle discovery and billing)
2. For full autonomy: PayGated (open source, self-hosted, npm install)
3. For agent-native payments: Circle Gateway (permissionless USDC, no accounts)
4. For crypto-only: CryptAPI (zero setup, 0.25% fee)

The MCP monetization space is moving fast. Six months ago none of these existed. Pick the one that matches your distribution strategy.