Developer documentation
ZadQ binds an x402 selling endpoint to a legally accountable operator: a KYC/KYB-verified legal entity backed by a guarantee deposit, issued and checked on the MintID identity network, where issuers are admitted and publish status on published terms. This documentation describes how the pieces fit together for integrators — the seller side, the buyer side, and the SDK.
The service is live and in early operations: endpoint publication and issuer registration are open.
The integration surfaces
| Surface | Who uses it | What it does |
|---|---|---|
| Seller integration | Operators of x402 selling endpoints | Attach the attestation to HTTP 402 responses |
| Buyer verification | Paying agents and their platforms | Check a seller's attestation locally, free of charge |
| SDK reference | Both sides | Vendorable snippets with graceful degradation built in |
| Agent tools and badge | Agents, their harnesses and any page showing a verdict | Two free MCP tools, the badge embed and the verification keys |
Design principles
- Free verification for the buyer. The verification path carries no
charge and no registration requirement.
- Graceful degradation always. Every integration keeps working when no
verdict is available: the badge falls back to the unknown state and the payment flow proceeds unchanged. Nothing in a third-party product depends on reaching ZadQ to function.
- No personal data. Attestation concerns legal entities and endpoint
identifiers. The integration surfaces carry no personal data.
- Open standards. "x402" (HTTP 402 Payment Required) is used
descriptively as the first supported rail; no affiliation is implied.
Where to start
- Operating a selling endpoint? Start with the
- Building a paying agent or a marketplace? Start with
- Looking for the code? The SDK reference lists the copy-in
modules and their contracts.
- Wiring an agent, or showing a verdict on a page? The
agent tools page covers the MCP tools, the badge and the verification keys.