x402's stream is centralised. sip402 decentralises it.

x402 already describes batch-settlement — streaming, session-based payments where you pay as a resource is delivered and settle in batches. But the only binding anyone shipped, cloudflare:402, is centralised: a credit balance the network holds, settled off-chain, with the network as merchant-of-record. You stream now and trust an intermediary to settle later. The trust-minimised, on-chain version was in the spec but never built.

sip402 builds it. One MetaMask ERC-7715 Advanced Permission becomes a standing, revocable session; an agent sips small USDC draws against it as a paid AI stream is delivered — batched on-chain, capped by ERC-7710 caveats, gasless via 1Shot, and cancellable mid-sentence. Money, caps, and revocation are on-chain; no intermediary ever holds the buyer's funds. x402 prices the request; sip402 prices the delivery.

A buyer grants one periodic delegation (the session). Each request, the buyer's agent signs a redelegation to the seller (the commitment). The seller verifies it by simulating the redemption, serves immediately, accumulates the voucher, and redeems a batch of vouchers in one transaction. The period caveat enforces the cap on-chain; revoking the root delegation makes the next draw revert.

Buyer (treasury smart account)
   │  openSession: ERC-7710 Erc20PeriodTransfer delegation, cap $X / period
   ▼
Agent (session key)        ← redelegateSession (A2A): orchestrator → specialists
   │  createCommitment: a redelegation agent→seller for this request's amount
   ▼
Seller (@sip402/server)
   │  verify by simulation · accumulate vouchers
   ▼
Delegation Manager ── redeemDelegations (BATCH) ──▶  USDC: treasury → seller
   ERC20PeriodTransferEnforcer caps the total; over-cap reverts (dry-tab)
   testnet: seller submits directly · mainnet: 1Shot relayer (gas in USDC)

Install the client and open a session against a USDC treasury.

pnpm add @sip402/client

# in your agent
import { openSession, createCommitment } from "@sip402/client";

# 1. one periodic grant (the tab)
const session = await openSession({ tokenAddress: USDC, periodAmount, periodDuration });

# 2. per request, sign a redelegation to the seller (the sip)
const commitment = await createCommitment({ session, payTo, amount });

The interactive Grant → Spend → Enforce demo ships with its own backend — it signs and submits real transactions, so it needs a funded key and an RPC, and runs on your machine rather than a static host. It lives in apps/demo.

# 1. clone + install (pnpm workspace)
git clone https://github.com/RomarioKavin1/sip402
cd sip402 && pnpm install

# 2. configure the demo backend
cp apps/demo/.env.example apps/demo/.env
#   PRIVATE_KEY=0x...          throwaway key, funded on Base Sepolia
#   SIP_NETWORK=base-sepolia
#   BASE_SEPOLIA_RPC_URL=https://sepolia.base.org

# 3. run (frontend + backend, port 3402)
pnpm --filter @sip402/demo dev
#   open http://localhost:3402

Connect MetaMask (Base Sepolia, with Advanced Permissions), approve one ERC-7715 grant, and the agent sips against it while the chain enforces the cap. Full prerequisites and troubleshooting are in apps/demo/README.md ↗.

The binding implements x402 batch-settlement across two networks (eip155:8453 Base mainnet, eip155:84532 Base Sepolia). Seven network requirements, summarized from the spec:

Every row is a real transaction. The counts differ on purpose: Base Sepolia is free, so every requirement is proven there; mainnet runs spend real USDC and gas, so the two production rails (gasless 1Shot redemption and paid Venice inference) are each proven once on Base mainnet.