add x402 overview

* add an overview section for x402

* fix tpyo

* fix typo

* add seller guide

Author: AyushBherwani1998

gator-sidebar.js

@@ -119,6 +119,7 @@ const sidebar = {
           collapsed: true,
           key: 'x402-guides',
           items: [
+            'guides/x402/overview',
             'guides/x402/seller',
             {
               type: 'category',

smart-accounts-kit/guides/x402/overview.md

@@ -0,0 +1,66 @@
+---
+description: Use x402 and ERC-7710 delegations to enable programmatic payments from MetaMask smart accounts.
+sidebar_label: Overview
+keywords: [x402, HTTP 402, ERC-7710, delegation, facilitator, payments, smart account]
+---
+
+import GlossaryTerm from '@theme/GlossaryTerm'
+import CardList from '@site/src/components/CardList'
+
+# x402 Payments
+
+[x402](https://www.x402.org/) is an open payment protocol that uses the HTTP `402` status code to enable programmatic, machine-to-machine payments over HTTP. It allows servers to charge for API access without requiring buyer accounts, API keys, or traditional payment infrastructure.
+
+For example, an AI agent can pay 0.01 USDC per request to access a weather API, or a
+dapp can charge users a micro-payment to retrieve premium onchain analytics data.
+
+## ERC-7710 payments
+
+The standard x402 protocol supports direct token transfers (using ERC-20 Permit2 or EIP-3009).
+[ERC-7710](https://eips.ethereum.org/EIPS/eip-7710) extends this by enabling <GlossaryTerm term="Delegation">delegation</GlossaryTerm>-based
+payments from <GlossaryTerm term="MetaMask smart account">MetaMask smart accounts</GlossaryTerm>.
+
+With ERC-7710, a buyer's smart account creates a delegation that authorizes the facilitator
+to transfer tokens on their behalf. The buyer doesn't sign a direct token approval.
+Instead, they sign a delegation that the facilitator redeems during settlement.
+
+This approach enables buyers to pay from MetaMask wallet.
+Buyers can restrict delegations to specific facilitator addresses, amounts, and time windows
+using <GlossaryTerm term="Delegation scope">delegation scopes</GlossaryTerm>.
+They can also create long lived delegations that allow recurring payments without re-signing
+for each request.
+
+Learn more [ERC-7710 delegations](../../concepts/delegation/overview.md).
+
+## Guides
+
+Get started with x402 payments in Smart Accounts Kit.
+These guides walk you through seller endpoint setup and buyer payment flows.
+
+<CardList
+items={[
+{
+href: '/smart-accounts-kit/development/guides/x402/seller',
+title: 'Set up a seller endpoint',
+description:
+'Configure a resource server that returns x402 payment requirements and settles requests.',
+},
+{
+href: '/smart-accounts-kit/development/guides/x402/buyer/delegations',
+title: 'Pay using a delegation',
+description: 'Create an ERC-7710 delegation and use it as the x402 payment payload.',
+},
+{
+href: '/smart-accounts-kit/development/guides/x402/buyer/advanced-permissions',
+title: 'Pay using Advanced Permissions',
+description:
+'Request ERC-7715 Advanced Permissions for x402 payments with a fixed allowance.',
+},
+{
+href: '/smart-accounts-kit/development/guides/x402/buyer/recurring-payments',
+title: 'Set up recurring payments',
+description:
+'Grant a periodic budget permission for recurring x402 payments.',
+},
+]}
+/>