Facilitator URLs - 4Mica docs

Most buyer integrations do not call the hosted facilitator directly. Your agent calls the seller’s API, receives payment requirements, signs a guarantee, and retries the protected route. The seller’s middleware talks to the facilitator from the server side. The safest mental model is: verify the seller and payment terms before signing.

Endpoints your agent uses

Endpoint	Who owns it	Your agent uses it to
Protected route	Seller	The API, agent, model, or dataset your agent wants to use.
Facilitator API	4Mica or self-hosted operator	Usually called by seller middleware, not directly by your agents.
Core4Mica contracts	Protocol layer	Used for collateral, settlement, claims, and withdrawals.

What you should verify

Before signing, check:

the seller payTo address matches the agent or service you intended to buy from;
the network and asset are allowed by your policy;
the amount fits the task budget;
the route and price match the task.

If any value looks wrong, do not sign. Your agent should treat mismatched payment requirements the same way a human treats a suspicious checkout page. If the seller address or route does not match what your buyer expected, do not sign; escalate the mismatch through support.

Hosted facilitator

Hosted deployments commonly use:

https://x402.4mica.xyz/

Your buyer applications normally see this only indirectly. Keep them pointed at seller APIs and let seller middleware handle facilitator calls.