SDK Features

This page tracks which features are implemented in each SDK (TypeScript, Go, Python v2).

Core

Component	TypeScript	Go	Python
Server	✅	✅	✅
Client	✅	✅	✅
Facilitator	✅	✅	✅

HTTP Framework Integrations

Role	TypeScript	Go	Python
Server	Express, Hono, Next.js, Fastify	Gin, net/http, Echo	FastAPI, Flask
Client	Fetch, Axios	net/http	httpx, requests

Networks

Network	TypeScript	Go	Python
evm (EIP-155)	✅	✅	✅
svm (Solana)	✅	✅	✅
tvm (TON)	❌	❌	✅
avm (Algorand)	✅	❌	❌
stellar	✅	❌	❌
aptos	✅	❌	❌
hedera	✅	❌	❌

Mechanisms

Scheme	Network	`assetTransferMethod`	TypeScript	Go	Python
exact	evm	`eip3009`	✅	✅	✅
exact	evm	`permit2`	✅	✅	✅
exact	svm	-	✅	✅	✅
exact	avm	-	✅	❌	❌
exact	stellar	-	✅	❌	❌
exact	aptos	-	✅	❌	❌
exact	hedera	-	✅	❌	❌
exact	tvm	-	❌	❌	✅
upto	evm	`permit2`	✅	✅	✅
batch-settlement	evm	`eip3009`	✅	✅	✅
batch-settlement	evm	`permit2`	✅	✅	✅

Extensions

Extension	TypeScript	Go	Python
bazaar (server)	✅	✅	✅
bazaar (facilitator client - list)	✅	✅	✅
bazaar (facilitator client - search)	✅	✅	✅
sign-in-with-x	✅	❌	✅
payment-identifier	✅	✅	✅
offer-receipt	✅	❌	❌
eip2612-gas-sponsoring	✅	✅	✅
erc20-approval-gas-sponsoring	✅	✅	✅

Client Hooks

Hook	TypeScript	Go	Python
onBeforePaymentCreation	✅	✅	✅
onAfterPaymentCreation	✅	✅	✅
onPaymentCreationFailure	✅	✅	✅
onPaymentResponse	✅	✅	✅
onPaymentRequired (HTTP)	✅	❌	✅

Server Hooks

Hook	TypeScript	Go	Python
onBeforeVerify	✅	✅	✅
onAfterVerify	✅	✅	✅
onVerifyFailure	✅	✅	✅
onBeforeSettle	✅	✅	✅
onAfterSettle	✅	✅	✅
onSettleFailure	✅	✅	✅
onVerifiedPaymentCanceled	✅	✅	✅
onProtectedRequest (HTTP)	✅	✅	✅

Facilitator Hooks

Hook	TypeScript	Go	Python
onBeforeVerify	✅	✅	✅
onAfterVerify	✅	✅	✅
onVerifyFailure	✅	✅	✅
onBeforeSettle	✅	✅	✅
onAfterSettle	✅	✅	✅
onSettleFailure	✅	✅	✅

Extension Hooks

Hook	TypeScript	Go	Python
enrichDeclaration	✅	✅	✅
enrichPaymentRequiredResponse	✅	❌	✅
enrichSettlementResponse	✅	❌	✅

Hook Adapter Features

Feature	TypeScript	Go	Python
Scheme-level lifecycle hook adapters	✅	✅	✅
Extension-level server lifecycle hook adapters	✅	✅	✅
Extension-level server HTTP transport hook adapters	✅	❌	✅
Extension-level client lifecycle hook adapters	✅	❌	✅
Extension-level client HTTP transport hook adapters	✅	❌	✅

MCP (Model Context Protocol)

Feature	TypeScript	Go	Python
MCP server payment wrapper	✅	✅	✅
MCP client (auto-pay tools)	✅	✅	✅
Bazaar discovery for MCP tools	✅	✅	✅

MCP Client Hooks

Hook	TypeScript	Go	Python
onPaymentRequired	✅	❌	❌
onBeforePayment	✅	❌	❌
onAfterPayment	✅	❌	❌

MCP Server Hooks (payment wrapper)

Hook	TypeScript	Go	Python
onBeforeExecution	✅	❌	❌
onAfterExecution	✅	❌	❌
onAfterSettlement	✅	❌	❌

HTTP Server Features

Feature	TypeScript	Go	Python
dynamicPayTo	✅	✅	✅
dynamicPrice	✅	✅	✅
paywall (browser UI)	✅	✅	✅

FacilitatorsProduction facilitator services for x402 payments.

⌘I