Listing/delisting watch

The problem it solves

Check admitted public evidence for a material listing or delisting event. Polling for this on a schedule wastes calls on windows where nothing moved, and still misses the change that lands between polls.

What a result looks like

A typed WATCH result: the subject's current evidence state, the material-change verdict for the window, freshness, evidence roots and the billing metric (CHECK or CHANGE). The exact schema is compiled into /catalog.json and /openapi.json.

Plain price

Checks $0.002 each \u00b7 material-change delivery $0.01

Check and change prices are the canonical catalog targets; the deterministic quote engine remains authoritative per request.

Freshness and evidence promise

Every check is source-grounded and freshness-stamped; a change delivery carries its evidence roots and stays replay-safe by idempotency id. An unchanged check is never billed as a change.

Try it with x402 / the API

Machines call the canonical payable endpoints - discovery starts atFor Machines, the live contract at /openapi.json, and the catalog at /catalog. Every inbound route resolves to the canonical x402 Revenue Collection Wallet; the address is advertised by the canonical surface, never copied onto this page.

Schema and docs

The result schema, examples, errors and payment semantics are compiled from the canonical catalog: see /catalog and the operation definitions in /openapi.json.

Related products

• Company filing/news watch
• Contract change watch

Monitoring and OEM path

Subscribe a subject once and receive material changes instead of polling. Subscription is an explicit buyer action - Arbiter never auto-enrols a caller.