Architecture

ArcenPay is a Web3 Entitlement and Autonomous Billing Layer designed for both human-facing SaaS applications and autonomous AI agents. Applications integrate through the React, Node.js, or Agent SDKs. ArcenPay handles plan state, subscriptions, feature access, hosted checkout, dual-mode payment links (/spec), webhooks, agent delegation mandates, commit-reveal escrow, and on-chain multi-chain settlement across EVM, Stellar Soroban, and Solana.

System layers

Layer	Responsibility
App & Agent SDKs	Embed billing UI, check entitlements, protect paid API routes, negotiate x402 payments, delegate mandates, and dispatch MCP tools.
Platform API	Stores catalog data, subscription state, invoices, webhooks, team settings, payment links, mandates, and escrow records.
Settlement engine	Runs renewals, settlement jobs, x402 verification, session vault accounting, and webhook dispatch.
Smart contracts	Enforce subscriptions, autopay limits, token transfers, protocol fees, and session vault balances on EVM, Stellar Soroban, and Solana Anchor.
ArcenAuth & Escrow	Evaluates hierarchical agent mandates, policy precedence, on-chain revocation invariants, and Verify-Then-Settle escrow.

Multi-chain settlement architecture

ArcenPay provides unified billing across EVM chains, Stellar Soroban, and Solana Anchor:

Network	Chain ID	VM	Environment	Canonical Token	Decimals	Role / Features
BOT Chain Mainnet	`677`	EVM	Production	`USDT`	`6`	Default production network; high-throughput execution, native gas (no native USDC — uses bridged USDT)
Solana Mainnet	`9100000`	Solana	Production	`USDC` (SPL mint `EPjFWdd5...`)	`6`	Production settlement via one Anchor program; shared-delegate autopay, relayer-submitted renewals
Arc Testnet	`5042002`	EVM	Development	`USDC` (`0x36000000...`)	`6`	Default development network; Circle Domain `26`, Gateway nanopayment routing
Base Sepolia	`84532`	EVM	Development	`USDC` (`0x036CbD53842c5426634e7929541eC2318f3dCF7e`)	`6`	Base testnet environment
Stellar Testnet	`9000001`	Soroban	Development	`USDC` (issuer `GBBD47IF...`)	`7`	Soroban testnet sandbox
Solana Devnet	`9100001`	Solana	Development	`USDC` (SPL mint `4zMMC9sr...`)	`6`	Solana developer environment (same program id as Mainnet)
Base Mainnet	`8453`	EVM	Coming soon	`USDC` (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`)	`6`	Low-cost L2 settlement with deep Circle USDC liquidity
Stellar Mainnet	`9000000`	Soroban	Coming soon	`USDC` (issuer `GA5ZSEJY...`)	`7`	Sub-second finality via Stellar Asset Contract (SAC)
BOT Chain Bohr	`968`	EVM	Not available	`USDT`	`6`	Staging stub for BOT Chain — no usable contracts
Sepolia	`11155111`	EVM	Reference only	`USDC` (`0x1c7D4B19...`)	`6`	Ethereum testnet reference / wallet auth

Chain definitions and deployed addresses are centralized in ArcenPay’s platform core and resolved automatically by all SDKs.

Contract surface

Contract	Role
`SubscriptionRegistry`	Mints and renews subscription NFTs and stores active subscription state.
`ERC7579AutopayModule`	Pulls approved stablecoins from subscriber accounts, applies protocol fees, and executes recurring renewals.
`PlanFactory`	Registers team plans and tier pricing on-chain.
`FeeCollector`	Receives protocol fees on subscription and settlement flows.
`SessionVault`	Holds agent session balances for x402 micropayments, escrow reservations, and on-chain revocation invariants.

On Solana, a single Anchor program fills every contract role above — Solana programs hold no state, so "config", "plan", "subscription", "subscription_delegate", and vault/settler PDAs hold what the EVM contracts store inline. The SDK resolves the same logical contract names on every family.

Dual-mode payment flow

ArcenPay supports both human interactive checkout and autonomous agent execution:

┌─────────────────────────────────────────────────────────────┐
│ Customer (Browser / Wallet)                               │
│   └─> ArcenEmbed / Hosted Checkout (/pay/[slug])          │
│         └─> Connects Web3 Wallet & Approves stablecoins   │
│         └─> ERC7579AutopayModule executes transfer        │
└──────────────────────────────┬──────────────────────────────┘
                               │
                               ▼
┌─────────────────────────────────────────────────────────────┐
│ AI Agent / Autonomous System                              │
│   └─> GET /public/payment-links/:slug/spec (machine spec) │
│   └─> ArcenAuth validates Mandate spending limits & policy│
│   └─> ArcenAgent signs on-chain transfer or escrow reserve│
└──────────────────────────────┬──────────────────────────────┘
                               │
                               ▼
┌─────────────────────────────────────────────────────────────┐
│ ArcenPay Platform                                         │
│   ├─> Ingests billing event with strict idempotency       │
│   ├─> Issues paid charge invoice & updates subscription   │
│   └─> Dispatches HMAC-signed webhooks to provider server  │
└─────────────────────────────────────────────────────────────┘

Provider configures catalog

The dashboard writes plan or payment link metadata to the platform API and syncs on-chain pricing through PlanFactory.

Customer or Agent resolves checkout

Human users open /pay/[slug] or ArcenEmbed. Autonomous agents fetch GET /api/v1/public/payment-links/:slug/spec or use the MCP tool arcenpay_resolve_payment_link.

Payment execution

For subscriptions, ERC7579AutopayModule executes the approved token transfer. For one-time payment links or API calls, tokens are transferred directly or reserved in SessionVault.

Platform updates entitlement state

The backend records payment, updates company balances, emits lifecycle events, and fires webhooks. SDK hooks (useEntitlement) reflect access immediately.

See How ArcenPay works for the end-to-end AI-agent lifecycle across these same rails.

x402 micropayments & Gateway nanopayments

Agent and API-payment flows use x402Middleware from @arcenpay/node. When an unpaid request hits a protected route, the middleware returns 402 Payment Required with payment specifications. ArcenAgent parses the challenge, signs payment, and retries automatically:

import { x402Middleware } from "@arcenpay/node";

app.use("/api/premium", x402Middleware({
  planId: "growth-api",
  ratePerCall: "0.001",
  chainId: 677, // BOT Chain Mainnet (or 9100000 Solana, 5042002 Arc, 84532 Base Sepolia)
}));

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Core concepts

Guides

Integrations

System layers

Multi-chain settlement architecture

Contract surface

Dual-mode payment flow

x402 micropayments & Gateway nanopayments

​System layers

​Multi-chain settlement architecture

​Contract surface

​Dual-mode payment flow

​x402 micropayments & Gateway nanopayments

System layers

Multi-chain settlement architecture

Contract surface

Dual-mode payment flow

x402 micropayments & Gateway nanopayments