x402 Payments Are Live on Solana: USDC Settlements and an MCP Registry Listing

Published: October 7, 2026

The same pay-per-query model that runs on the XRP Ledger now settles in USDC on Solana mainnet — real money moving, not a testnet demo. And our MCP server is now listed in the official MCP Registry, so agents can find it without being handed a URL.

What changed

Two things shipped, and both are live rather than planned:

Solana USDC settlement is on. The Solana routes serve a standard 402 Payment Required and settle in USDC on Solana mainnet. Roughly 28 country routes are exposed publicly.
Our MCP server is discoverable. It is published to the official MCP Registry as io.github.DaimyoVegan/xrplme-paid, pointing at https://api.xrplme.online/mcp.

Solana: what a caller actually gets

Hit a Solana route with no payment and you get the terms back — verified live against /wc/v1/thailand/bot-solana:

network   : solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp
asset     : EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v   # native USDC
amount    : 50000                                            # 0.05 USDC
payTo     : 5KMiN7b7qBAqE2o5ucoCJ5xH9vZaFfzvq3dHeiGGvcMw
feePayer  : 32jx1jS6Dkkf7fuGv33h1rVgbAaMHNtnVbGkTWhW8heL
qrData    : solana:5KMiN7b7qBAqE2o5ucoCJ5xH9vZaFfzvq3dHeiGGvcMw?amount=0.05

The qrData field is a Solana Pay URI, so a phone wallet can scan it directly. The feePayer is the part that makes this work for a buyer: the payer needs USDC and nothing else — no SOL required to cover network fees.

Price note

A standard query is 0.05 USDC; the AI-enhanced query is 0.25 USDC. On the XRP Ledger the equivalent tiers are 0.1 XRP and 0.5 XRP.

How the fee is paid (and why that matters)

Settlement runs through a facilitator we host ourselves, using the facilitator that ships inside the x402 SDK. That means no third-party facilitator fee and no third party able to gate the collector address. Two wallets are involved, with deliberately separate jobs:

Role	Holds	Key location
Collector (`payTo`)	All USDC and XRP revenue	Not on the server — address only
Fee payer	SOL for network fees	Server, in a `0600` env file
Payer (buyer)	USDC only	Buyer’s wallet

The receiver never pays the network fee. Separating the gas wallet from the collector means the wallet holding revenue does not need its key on the server at all.

Receipts

These are mainnet settlements, each one a real token movement. They are public and independently checkable on any Solana explorer:

Standard HTTP query — eYLA2dFhMrYc9wQKjteugDhZN4DLRty2qkkoHzsTe2Q9BPCsJ4QFXekbviwrKyMn8TCmLtwKa5fVMfGYfiv3fZu
AI-enhanced query — 2WGX95Gds1gYxuuG86kc1WU61fiuv9EWKj2T3b1wYU1HEwKUsvFAEkuvJYKCyAHoGtLz7sQ8PjwHNHcTbXJEynPB
MCP tool (country schema) — 45Cr4sHxsE2xFq9bAX13c4ou875r24Zyqgw8esqv4ECPhdEpNRkmVnjE75ymoEE559xuXzrABj64X4fSEBFhrsmc
MCP tool (country data) — wVSt5dAyRHr1vKGtnsGb9jx3Ryw9e9aa9JMHny6zzrJufwkFc49SBSg3xRvZNjoRG5Vsw4A52MRFo9JWsQaGE7J

The MCP Registry listing

Until now, using the API meant already knowing the URL. Agents now have a discovery path: the server is indexed in the official MCP Registry under io.github.DaimyoVegan/xrplme-paid.

Field	Value
Registry name	`io.github.DaimyoVegan/xrplme-paid`
Transport	`streamable-http`
Endpoint	`https://api.xrplme.online/mcp`

The registry entry advertises the free discovery tools and the paid tools. The paid ones demand payment correctly — calling one without paying returns a payment-required error naming both rails and their prices, rather than returning data.

Payment is the authentication

There are no accounts to create and no API keys to manage. Each endpoint answers with a 402 carrying its terms; you pay, then retry the request with the payment signature and receive the data. The free API docs walk through the full flow, and the developers page has runnable client examples.

What we have not done yet

The Solana AI tier is wired but the MCP paid tools are the primary paid surface today. There is not yet a public source repository for the server itself, and the MCP Registry is in preview — its own documentation warns of possible breaking changes or data resets before general availability, so a listing there may need re-publishing.

Try it

curl -X POST https://xrplme.online/wc/v1/thailand/bot-solana \
  -H "Content-Type: application/json" \
  -d '{"message":"What are the current visa and entry requirements?"}'

Expect a 402 with the terms above. Coverage spans 30 countries. Data is informational only and is not legal advice.

Related reading: x402.org — the payment protocol; xrpl.org — the XRP Ledger; solana.com — Solana documentation; the MCP Registry.