⚡ A-Pay Protocol (AgentPay)

The World's First Fully Autonomous HTTP 402 Micropayment & Economic Settlement Layer on Base L2

🌐 Canonical Protocol Identity & Verified Network

• Official Protocol Domain: https://apayprotocol.org (Cloudflare Global Edge Anycast, DDoS Protected)
• Official Basename (Base L2 ENS): apayprotocol.base.eth
• Official WordPress Plugin: https://wordpress.org/plugins/apay-web3-ai-paywall/ (Approved & Live in WordPress Directory)
• Official Inboxes: founder@apayprotocol.org | contact@apayprotocol.org | security@apayprotocol.org
• Official GitHub Organization: https://github.com/apayprotocol (Verified Domain Organization)
• Official GitLab (Decentralized Mirror): https://gitlab.com/apayprotocol/a_pay (Continuous Edge Delivery Mirror)
• Live Web App & Developer Console: https://apayprotocol.org
• Technical Whitepaper: https://apayprotocol.org/whitepaper
• Founder & Lead Architect: Sagar Yadav
• Official Telegram: https://t.me/apay_protocol | Bot: @APay_Protocol_Bot

⛓️ Verified Smart Contracts (Base Mainnet — Chain ID 8453)

🧪 Base Sepolia Testnet (Chain ID 84532)

• Testnet Faucet APAY: 0x8dd4ff9035c7d4e0Bef30aa64FC30d128A4066C3
• EscrowVault: 0x3E35a9E802627a3D9A86D6554e72b1C446E34aAF
• APayRouterV2: 0xD08c8A337E5339d1c083E06d74A9265956ceEA16
• APayRouter V1: 0x71434344beEF9C44fF3BC95572bEB7bFB8847ec6

💡 The Genesis: Unlocking HTTP 402 After 30 Years

In 1996, Sir Tim Berners-Lee and the IETF authored RFC 2068, reserving the HTTP status code 402 Payment Required for digital cash protocols.

For thirty years, status code 402 sat dormant. Web 2.0 forced digital payments into human-centric credit card rails (Visa, Mastercard, Stripe), requiring KYC identity checks, CAPTCHAs, and minimum fixed transaction fees of $0.30 + 2.9%.

⚠️ The Problem Today (2026 AI Agent Economy)

1. AI Agents Have No Credit Cards: Autonomous software agents (Claude Desktop, Cursor, LangChain, AutoGen, CrewAI) execute multi-step workflows across the web. They cannot hold credit cards, submit passports for KYC, or solve visual captchas.
2. Publishers & Website Owners are Bleeding Compute: Autonomous AI scrapers (GPTBot, ClaudeBot, PerplexityBot) crawl millions of pages daily. Publishers face massive server bandwidth bills while their proprietary intelligence is consumed for free.
3. Stripe Kills Micropayments: If an AI agent wants to purchase a single database row, an API call, or an article for $0.001 (0.1¢), Stripe's $0.30 fixed fee makes it impossible.

🌟 The A-Pay Solution

A-Pay is the world's first autonomous economic settlement layer that implements the native HTTP 402 standard on Base Layer 2.

• Sub-Cent Micropayments: Settle transactions as small as $0.0001 (0.01¢) in native USDC or $APAY.
• Zero Gas Friction for Agents: Agents sign off-chain cryptographic authorizations (EIP-712). Relayers handle batch settlement on Base L2.
• Sub-15ms Latency: Cryptographic verification completes in under 15 milliseconds, seamlessly unblocking HTTP responses.
• 100% Non-Custodial & Audited: Guarded by smart contract session keys with daily spending limits and per-call caps.

🏛️ The Three Architectural Pillars

                                      A-PAY PROTOCOL
                                            │
         ┌──────────────────────────────────┼──────────────────────────────────┐
         ▼                                  ▼                                  ▼
   [PILLAR 1: SELLER]                 [PILLAR 2: BUYER]               [PILLAR 3: SETTLEMENT]
  HTTP 402 Paywall Layer            Autonomous Agent Wallets            Base L2 Escrow Vault
  ──────────────────────            ────────────────────────            ────────────────────
  • WordPress AI Paywall Plugin     • Model Context Protocol (MCP)      • EIP-712 Batch Settlement
  • Reverse Proxy (`apay protect`)  • Ephemeral Session Keys            • Non-Custodial Escrow
  • FastAPI / Express Decorators    • Daily Budgets & Per-Call Caps     • Cumulative Payment Channels
  • Next.js 15 Middleware           • LangChain / CrewAI Wrappers       • Native USDC & $APAY Support

Pillar 1: HTTP 402 Paywall & Monetization Layer (For Publishers & Sellers)

Turn unmetered AI crawler traffic into instant, automated revenue:

• Selective Bot Paywall: Genuine human visitors read your website freely without popups or captchas. Autonomous AI crawler bots automatically receive an HTTP 402 Payment Required challenge.
• Instant Reverse Proxy: Protect ANY existing REST API, FastAPI backend, or web server with a single terminal command:

  apay protect --target http://localhost:8000 --price 0.001 --wallet 0xYourPayoutAddress
  

• Native Framework SDKs: Drop-in middleware for Next.js 15, FastAPI, Express.js, and WordPress.

Pillar 2: Autonomous Agent Wallet & MCP Server (For AI Agents & LLMs)

Give AI agents economic agency with programmatic safety rails:

• Model Context Protocol (MCP): Native integration for Claude Desktop, Cursor, Cline, Windsurf, and custom LLM tool runners.
• Spending & Counterparty Guardrails: Define hard spending limits (daily_budget_usdc=2.00, max_per_call_usdc=0.01) and opt-in verified seller verification (verify_seller_seal=True via SealKeeper). The agent cannot exceed its delegated allowance or settle with unproven/withheld sellers.
• Auto-Settling HTTP Client: APaySession automatically catches 402 headers, checks seller reputation/SEAL, signs the EIP-712 challenge, and retrieves data in a single round-trip without human intervention.

Pillar 3: On-Chain Base L2 Settlement & Escrow Vault (For Enterprise Web3 Security)

Enterprise-grade cryptographic settlement built on Coinbase's Base Layer 2:

• EscrowVault: Agents deposit or lock funds into dedicated smart contracts. Session keys authorize payments without holding root private keys.
• APayRouterV2: Batch settlements aggregate thousands of off-chain micro-signatures into a single Merkle-verified on-chain transaction, reducing effective gas costs to fractions of a cent.
• Dual-Currency Support: Settle in dollar-pegged USDC or the protocol utility token $APAY with fee discounts.

👥 Who Is A-Pay For? (Target Personas & Benefits)

🚀 Quickstart & Universal Developer Setup

1. Python Developers (FastAPI & AI Agents)

pip install apay

Protect a FastAPI Endpoint with HTTP 402:

from fastapi import FastAPI, Depends
from apay import require_payment

app = FastAPI()

@app.get("/api/alpha-feed")
@require_payment(price_usdc=0.005, receiver="0xYourPayoutWalletAddress")
async def get_alpha_feed():
    return {"status": "unlocked", "data": "Exclusive proprietary real-time signals"}

Call Protected APIs with an Autonomous Agent:

from apay import APaySession, AgentWallet, check_seller_seal

# Create an agent wallet with strict safety caps
wallet = AgentWallet(
    private_key="0x...",
    max_per_call_usdc=0.01,
    daily_budget_usdc=5.00
)

# Enable verified seller guardrail (SealKeeper SEAL integration)
# When True, verifies seller's cryptographic EdDSA SEAL signature and ensures
# wallet ownership is proven (wallet.proven === True) before signing payment.
session = APaySession(wallet, verify_seller_seal=True)

# Automatically handles HTTP 402 challenges & settles on the fly (<15ms)
response = session.get("https://api.example.com/api/alpha-feed")
print(response.json())

# Standalone seller SEAL lookup:
status = check_seller_seal("0x7dfc75477f00c65f7b611f194d282d8b5a6f30dc")
print("Seller proven:", status["proven"], "Handle:", status.get("handle"))

2. TypeScript & Node.js Developers (Next.js & Express)

Scaffold a complete fullstack project in 30 seconds:

npx create-apay-app my-autonomous-agent

Or install the gateway & agent library:

npm install apay-gateway viem

import { APayClientTS, AgentWalletTS, checkSellerSeal } from "apay-gateway";

const wallet = AgentWalletTS.create({
  privateKey: process.env.AGENT_PRIVATE_KEY as `0x${string}`,
  maxPerCallUsdc: 0.05,
  dailyBudgetUsdc: 2.0,
});

// Initialize client with opt-in SealKeeper verified seller guardrail
const client = new APayClientTS(wallet, {
  verifySellerSeal: true, // Rejects unproven, withheld, or invalid seller SEALs
});

// Auto-settling request with verified seller check (<15ms)
const res = await client.fetch("https://data-provider.com/market-depth");
const data = await res.json();
console.log(data);

// Standalone seller SEAL verification:
const seal = await checkSellerSeal("0x7dfc75477f00c65f7b611f194d282d8b5a6f30dc");
console.log("Seller proven:", seal.proven, "Handle:", seal.handle);

3. Claude Desktop & Cursor (Model Context Protocol / MCP)

One-Click Install via Smithery:

npx -y smithery mcp add apayprotocol/apay

Or Add to claude_desktop_config.json / Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "apay": {
      "command": "uvx",
      "args": ["apay", "mcp"],
      "env": {
        "APAY_NETWORK": "base-mainnet",
        "APAY_CURRENCY": "DUAL",
        "APAY_MAX_PER_CALL": "0.05",
        "APAY_DAILY_BUDGET": "2.00"
      }
    }
  }
}

Now Claude or Cursor can execute tools:

• apay_request: Send requests to HTTP 402 protected APIs and settle on-the-fly.
• apay_get_balance: Inspect live on-chain balances (ETH, USDC, $APAY).
• apay_inspect_endpoint: Probe an API paywall for price and terms without spending gas.
• apay_set_budget: Adjust per-call limits and daily spending guardrails.

4. Website Owners & WordPress (Zero Code Reverse Proxy)

Protect ANY live web server or WordPress site without changing a single line of backend code:

apay protect --target http://localhost:8000 --price 0.001 --wallet 0xYourPayoutAddress

• Human browsers view the site freely.
• AI web crawlers (GPTBot, ClaudeBot, Bytespider) receive an HTTP 402 challenge and pay per scrape.

5. Coinbase AgentKit (On-Chain Base L2 Agents)

Drop-in Action Provider enabling any Coinbase AgentKit agent to probe and settle HTTP 402 micropayments on Base L2:

Python:

from apay.integrations.agentkit import create_apay_action_provider

apay_provider = create_apay_action_provider(
    network="base-mainnet",
    max_per_call_usdc=0.05,
    daily_budget_usdc=2.00,
)

TypeScript:

import { createAPayActionProvider } from "apay-gateway/agentkit";

const apayProvider = createAPayActionProvider({
  network: "base-mainnet",
  preferredCurrency: "USDC",
});

Provides 5 native tools: apay_probe_endpoint, apay_request, apay_get_wallet_status, apay_get_balance, apay_set_budget.

📂 Project Architecture

a_pay/
├── src/apay/                # Core Python SDK & Runtime
│   ├── cli.py               # ⚡ 1-Command CLI (`apay protect`, `apay wallet new`, `apay mcp`)
│   ├── client.py            # 🤖 Autonomous HTTP client with auto-402 negotiation
│   ├── wallet.py            # 🔐 In-memory delegated wallet & spending limits
│   ├── proxy.py             # 🛡️ Ultra-light reverse proxy HTTP 402 paywall
│   ├── relayer.py           # 📊 EIP-712 batch settlement relayer
│   └── integrations/        # 🔗 LangChain, CrewAI & AutoGen agent wrappers
├── gateway-ts/              # Enterprise TypeScript Gateway & EIP-712 Verifier
├── packages/create-apay-app # Official NPX starter scaffolding CLI
├── contracts/               # Audited Solidity Smart Contracts (Base Mainnet & Sepolia)
│   ├── APAYToken.sol        # ERC-20 100M Cap Protocol Utility Token
│   ├── EscrowVault.sol      # Session Key Delegated Spending Vault
│   ├── APayRouterV2.sol     # Cumulative Channel & Merkle Root Router
│   └── StakingVault.sol     # Anti-Spam Collateral Engine
├── web/                     # Official Portal (Next.js 15, Tailwind, RainbowKit, Wagmi)
├── docs/                    # Complete Protocol Specifications & RFCs
├── spec/                    # RFC wire format & EIP-712 domain specifications
└── pyproject.toml           # Official Hatchling packaging configuration

🔒 Security & Verification Guarantees

1. Non-Custodial Session Delegation: Agents operate with strictly sandboxed session keys. The agent NEVER has access to the owner's primary root wallet or vault withdrawal functions.
2. Deterministic Cryptographic Limits: Spending caps are signed off-chain and enforced both in-memory and on-chain by the EscrowVault smart contract.
3. Formal Verification & Secrets Hygiene:
   • Zero hardcoded secrets, seed phrases, or private keys across the entire codebase.
   • Automated security scans verified via python3 scripts/scan_secrets.py.
   • On-chain bytecode verified on BaseScan.

🤝 Community & Ecosystem

• Official Website: https://apayprotocol.org
• Technical Whitepaper: https://apayprotocol.org/whitepaper
• Founder & Lead Architect: Sagar Yadav
• Official Telegram: https://t.me/apay_protocol | Gateway Bridge
• Official Discord: https://discord.gg/cW2WRSfb35 (Developer Community)
• Official Subreddit: r/A_Pay_Protocol
• GitHub Organization: https://github.com/apayprotocol
• Official Basename: apayprotocol.base.eth
• Contact & Security: founder@apayprotocol.org | security@apayprotocol.org

A-Pay is an open-source decentralized economic protocol for the machine-to-machine economy. Built on Base Layer 2.