I made Korean government data agent-payable with MCP and x402 — here's what actually happened

I built a remote MCP server that enables AI agents to verify Korean businesses using official National Tax Service data and charge for it per call in USDC via x402. This server works end-to-end, as demonstrated by the first on-chain payment where an agent paid $0.02 and received real government data back without any human intervention.

The server is now listed on the x402 Bazaar, which is Coinbase's discovery catalog for agent-payable APIs, and is currently at the top for Korean business registration verification. The server was built using NTS public API, TypeScript, and the MCP SDK, and deployed on Cloud Run, which incurs negligible idle costs. It offers three pricing options: 10 calls/day for free, $0.02 per status check, $0.05 per identity verification, and $0.02 per company for batch requests, all paid in USDC via x402.

The build, deployment, and verification process cost approximately $3. The server avoids human interaction by managing payments and providing data. While directory listings can bring traffic, they are not a reliable popularity metric; the focus should be on actual tool calls. The free tier can disqualify a resource from payment marketplaces, so it's better to default to paid.

The MCP registry sometimes rejects new publishes due to schema changes, and x402 moved to v2 while tutorials still show v1. Cloud Run's URL propagation can take up to four hours. Building this system cost only about $3, and it took only a few weekends. This server offers a unique corner of the market where Korean official data and agent-payable services intersect, and there's room for growth as agentic procurement becomes more common.