WDK Docs

API Reference Skeleton

Backward-compatible endpoint contracts for WDK + USDT0 flows.

⌘KCommand-palette first navJump:Quickstart API Errors Migration Security

Call Endpoint Playground

Left pane configures request parameters and signing mode.

Split-pane Inspector

Shows raw headers, PAYMENT-REQUIRED, computed signature, and facilitator response.

POST /api/v1/liquidity/quote

Preflight route selection for USDT0/USDT/USDC settlement.

Request payload

{"invoiceId":"inv_123","walletAddress":"0x...","sourceAssets":["USDT0","USDT","USDC"],"constraints":{"maxFeeBps":75,"maxLatencyMs":12000}}

Response payload

{"quoteId":"q_123","expiresAt":"2026-02-18T12:00:00.000Z","routes":[{"routeId":"r_fast","sourceAsset":"USDT0","sourceChain":"eip155:42161","destinationChain":"eip155:8453","authType":"eip3009","estimatedFeeBps":42}]}

POST /api/v1/router/settle

Submit signed payment intent for settlement execution.

Request payload

{"quoteId":"q_123","routeId":"r_fast","client":{"type":"wdk","version":"1.0.0"},"authType":"eip3009","amount":"1.00","asset":"USDT0","payment":{"scheme":"exact","authorization":{"from":"0x...","to":"0x..."}}}

Response payload

{"settled":true,"facilitatorId":"p402-eip3009","receipt":{"txHash":"0x...","sourceAsset":"USDT0","sourceChain":"eip155:42161","destinationChain":"eip155:8453","routeId":"r_fast"}}

Asset/Auth capability matrix (EVM)

Asset Class	EIP-3009 Path	Recommended x402 Handling	Notes
USDT0 (supported deployments)	Yes	Prefer authType=eip3009	Validate exact contract surface per chain/version.
Legacy USDT	No (generally)	Permit/transfer fallback or bridge to USDT0	Do not assume transferWithAuthorization.
USDC	Yes	Standard eip3009 flow	Current baseline implementation in P402.

Upstream validation gates (before GA)

Cross-check all WDK adapter method names and data contracts against tetherto/wdk examples.
Validate chain and token support claims against official docs for Build with AI workflows.
Add compatibility table: WDK version -> P402 SDK version -> supported auth types.

WDK API conformance table (fill before GA)

Upstream Surface	Exact Type Signature	P402 Wrapper	Status	Source Link
<methodName>	<type>	<adapter>	planned	<source>