The Payment Protocol the On-Chain Web Has Been Waiting For
Arcenpay4 min read·Just now--
There’s a version of the internet being built right now where software pays for software, AI agents transact without human approval, and subscriptions are smart contracts, not database rows in a Stripe account.
Most payment infrastructure wasn’t built for that internet. ArcenPay was.
What ArcenPay Actually Is
ArcenPay is an on-chain payment protocol. Not a crypto-flavoured Stripe wrapper. Not a fiat-to-crypto ramp. A protocol which means the core primitives are smart contracts deployed on-chain, readable by anyone, auditable by default.
It handles three things that no existing payment infrastructure handles well together:
- x402 payment verification — signed HTTP payment headers for machine-native transactions
- On-chain subscriptions — recurring billing via smart account modules, no wallet prompt per cycle
- Agent payments — autonomous settlement for AI agents operating without human approval
Each of these is a solved problem in isolation. ArcenPay is the first protocol that ships all three as a unified stack.
x402: The Payment Primitive the Web Always Needed
HTTP 402 — “Payment Required” — has been a reserved status code since the early internet. It was always intended for machine-readable payment flows. It was never standardised.
The x402 protocol changes that. Here’s how it works in ArcenPay:
A client requests a paid resource. The server returns a 402. The client attaches a signed x402 header, containing payment proof, a timestamp window, and a unique nonce and retries. ArcenPay’s Facilitator validates the signature in under 50ms and serves the resource.
No redirect. No hosted checkout page. No custodian. Replay attacks are structurally impossible because each header is a one-time, time-bounded proof.
This isn’t a UX improvement. It’s a new payment primitive the one that works for browsers, APIs, and AI agents equally.
Subscriptions Without the Broken Parts
The recurring billing problem in crypto has always been this: wallets don’t allow pull-based charges. Every billing cycle requires explicit user approval. That’s not a subscription model, it’s a monthly prompt.
ArcenPay solves this with three contract layers working together.
PlanFactory publishes subscription plans directly on-chain. Every plan is an immutable contract record with a transaction hash. Not a row in a database.
SubscriptionRegistry handles subscriber state. When a user subscribes, they mint an ERC-5643 NFT a token standard specifically designed for time-bound, renewable access. The NFT carries expiry timestamps. Subscription status is readable directly from chain state.
ERC-7579 Smart Account Modules handle the billing automation. A module installed on the user’s smart account is authorised to execute recurring USDC pulls on the billing interval. No wallet prompt every month. To cancel, the user uninstalls the module. Cancellation is self-sovereign, no trusting the merchant to process it.
The result: recurring billing that works the way cards work, but on-chain, non-custodial, and auditable by anyone.
Agent Payments: The Part Nobody Else Has Built
This is where ArcenPay is genuinely ahead of the category.
AI agents are becoming economic actors. They access APIs, purchase compute, execute tasks. The current infrastructure for this is embarrassing, API keys tied to credit cards, no spending controls, no audit trail, no autonomy limit.
ArcenPay’s agent payment model:
- An agent pre-funds a SessionVault with USDC — establishing a hard spending cap for the session
- ArcenPayAgent intercepts
fetch()calls from the agent runtime and automatically attaches x402 payment headers - Settlements log against the vault balance in real time
- When the vault empties, spending stops — no overruns, no surprise charges
- Every settlement is an on-chain event, permanently verifiable
This is the payment primitive the agentic web requires. Pre-funded, cap-bounded, autonomously settling, fully auditable. No human in the loop. No unlimited liability.
The Developer Stack
ArcenPay ships as three packages:
@arcenpay/react — drop-in UI components: CheckoutModal, PricingTable, SubscriptionStatus, FeatureFlagGuard. Wallet-native, no iframes, no redirects.
@arcenpay/sdk — ABIs, contract addresses, 50+ TypeScript types. Type-safe from checkout to entitlement check.
@arcenpay/agent — the autonomous payment runtime for AI agent contexts.
Setup is a single provider. Three lines to wrap your app. wagmi v2 and viem v2 built in.
Who It’s For
If you’re building a Web3 protocol, a DeFi product, an AI-native application, or any product where non-custodial settlement, recurring on-chain billing, or autonomous agent payments are requirements — ArcenPay is built for your stack.
Developer plan is free. Waitlist is open at arcenpay.com.
The on-chain web is being built right now. The payment infrastructure should match.The Payment Protocol the On-Chain Web Has Been Waiting For
There’s a version of the internet being built right now where software pays for software, AI agents transact without human approval, and subscriptions are smart contracts, not database rows in a Stripe account.
Most payment infrastructure wasn’t built for that internet. ArcenPay was.
