402md Facilitator Documentation

Cross-chain USDC settlement for agentic payments. Buyer pays on any supported chain, seller receives on theirs.

I want to…	Go to
Learn by following a guided, end-to-end example	Tutorials
Solve a specific problem with step-by-step instructions	How-to guides
Look up exact API fields, env vars, chains, error codes	Reference
Understand why the system is designed this way	Explanation

Quick links by audience

I'm a seller integrating x402 or MPP. Start with the first payment tutorial, then bookmark the API reference and the seller how-to guides.

I'm operating a self-hosted facilitator. Read deploy relay and worker and the environment variables reference. Keep the monitoring guide handy.

I'm contributing to the repo. Start with set up dev environment and the architecture explanation.

I'm evaluating the project. Read the architecture explanation, then why CCTP V2 and non-custodial model.

Contents

Tutorials — learn by doing

• Your first cross-chain payment
• Build a paywalled API with x402

How-to — solve a specific problem

• For sellers: register, accept multiple chains, use MPP on Stellar, check settlement status, top up with on-ramp
• For operators: run the local stack, deploy relay and worker, monitor Temporal workflows, trigger circuit breakers
• For contributors: set up dev environment, add a new EVM chain, write a network adapter, run the demo

Reference — look it up

• API overview
• API endpoints: sellers · settlements · MPP · discovery (bazaar) · on-ramp · health
• Supported chains
• Fees and gas schedule
• Environment variables
• Error codes
• CLI and scripts

Explanation — understand the design

• Architecture overview
• Why CCTP V2
• Non-custodial settlement (Model A)
• x402 and MPP — dual protocol
• Temporal workflows and durability
• Security model
• merchantId as a primitive