Preface

This project was honestly started as a way to mess around with the x402 standard given life by coinbase and cloudflare, I thought it was interesting and could provide a clear standard on how people go about accepting payments via crypto for services in a secure and private manner if the right steps are taken to privately acquire usdc on their supported networks.

But that's not reliable enough in terms of privacy and the answer to it already existed, Monero/XMR. Since it's almost a given coinbase themselves wouldn't support XMR in the standard facilitator, I needed a purpose built tool but decided this needs to be available to others wanting to accept monero alongside their services.

The project is opensource and available to be used alongside other's projects, it requires at least running your own monero-wallet-rpc instance but you could also use your own node for connecting the rpc. Recommended ona view only wallet.

Links: our git instance // github instance

the rest of this post is currently ai generated, I'll be rewriting it soon, as I believe the ai agent premise of x402 is mostly marketing hype and MAYBE a future promise, but the current reality is a standard way to allow payments for a service

Beyond the Public Ledger

While USDC on Base provides the speed and low fees required for autonomous agents, it remains a transparent ledger. For high-adversary environments and true privacy-focused engineering, a public trail is a vulnerability.

Today, we are announcing the Universal XMR Facilitator—a sidecar addition to the x402 standard that brings the absolute anonymity of Monero to the orchestration of ephemeral infrastructure.

The Challenge: Identity without a Sender

The x402 protocol (initially standardized by Coinbase) relies on knowing who paid to grant access to a resource. Monero, by design, has no "From" address on-chain. It is a ghost chain.

To solve this for the Entropy ecosystem, we implemented a Deterministic Identity Bridge.

How it Works:

1. The Merchant (Vending Machine): Generates a stable PayerID for the user, derived either from an EVM key or a hash of a Monero primary address.
2. The Shield: Before calling the Facilitator, the Merchant hashes the PayerID again. The Facilitator never sees your real identity.
3. The Proof: The Facilitator utilizes Monero's check_tx_key RPC method. It doesn't need your private keys; it only needs a transaction ID and a transaction key to verify that "someone" sent the exact amount to a unique subaddress.
4. The Settlement: Once verified, the Facilitator hands back the identity hash to the Merchant, who maps it to your resource.

Hardened for the Real World

Our Rust-based Facilitator is designed for high-uptime, low-trust environments:

• Non-Custodial: The facilitator verifies proofs without ever holding user funds.
• Automated Reaper: Stale invoices are purged hourly to prevent database bloat and mitigate price volatility.
• Mempool Resilience: A robust retry loop handles the "lag" of RPC nodes, ensuring transactions are caught as soon as they hit the mempool.

Why this matters for Agents

An AI agent can now provision a high-performance VPS from providers like Hetzner with zero financial footprint. No credit cards, no exchange-linked wallets, no forensic trail. Just code and privacy.

The XMR Facilitator is currently running as a sidecar to the X402 Gateway. It is a universal component—ready to be dropped into any project following the x402 standard.

Compute is now untraceable.

Stay Anonymous.