Architecture

Scribe Finance is organized as five layers, each with one clearly bounded responsibility. Understanding any layer in isolation is enough to work with it; this page then shows how they compose.

The five layers

Layer	Responsibility
Protocol Layer	The x402 and MPP HTTP handshake: how agents and services negotiate payment terms.
Settlement Layer	Robinhood Chain mainnet, settling USDG as a standard ERC-20 token with near-instant sequencer confirmation and sub-cent fees.
Contract Layer	Scribe Finance’s Solidity contracts: subscription delegation, the plan registry, and session management.
Facilitator Layer	Nodes that verify payment headers and initiate on-chain settlement.
SDK Layer	TypeScript libraries that collapse the layers above into `scribefinance.pay()` and `scribefinance.subscribe()`.

Request flow

An agent’s first request for a paid resource proceeds as follows.

Agent
  |
  |  1. GET https://api.example.com/v1/data
  v
Service Provider API
  |
  |  2. 402 Payment Required
  |     X-ScribeFinance-Payment: { plan, amount, token, network, ... }
  v
Agent + Scribe Finance SDK
  |
  |  3. Reads payment terms
  |     Signs delegation or transfer via wallet
  v
Scribe Finance Facilitator
  |
  |  4. Verifies authorization on-chain
  |     Executes or schedules transfer via the Scribe Finance contracts
  |     Returns confirmation header
  v
Service Provider API
  |
  |  5. Validates confirmation
  |     200 OK + requested resource
  v
Agent

With an active subscription in place, steps 2 through 4 disappear: the service verifies the subscription directly on-chain and serves the resource immediately.

Protocol Layer

Negotiation lives at the HTTP level. Scribe Finance implements the x402 specification: an unauthenticated request draws a 402 Payment Required status with a structured payment object in the response headers, and the agent replies with a signed payment or subscription authorization.

The payment header schema is deliberately parseable by MPP-compliant agents as well. Where MPP routes to Stripe/Tempo infrastructure, Scribe Finance routes to Robinhood Chain, and because only the network field of the payment object differs, an MPP agent can consume Scribe Finance endpoints without a code change.

Settlement Layer

Value moves exclusively on Robinhood Chain mainnet. Scribe Finance builds on the standard ERC-20 interface; during the beta, the primary payment token is USDG (Global Dollar), the Paxos-issued stablecoin native to Robinhood Chain. Robinhood Chain is an Arbitrum Orbit Ethereum L2 targeting ~100ms block times: the sequencer confirms near-instantly, full finality arrives when the batch settles on Ethereum, and fees remain well under a cent per transaction. Those properties make rapid per-request payments and small metered charges routine rather than exceptional.

Scribe Finance keeps no ledger of its own. Plans, subscriptions, allowances, and payments exist as publicly readable contract records, written to the chain. The chain is the source of truth.

Contract Layer

The core on-chain logic is a set of open-source Scribe Finance contracts, written in Solidity 0.8 with OpenZeppelin and deployed on Robinhood Chain. The Scribe Finance Subscriptions contract is deployed at 0xde1e6a7e615c023c014171bc46cc764cedcf1df6; an external security audit is planned before the beta concludes. Beyond subscriptions, the contracts define:

Scribe Finance Plan Registry: the on-chain catalog of provider pricing plans. Plans are immutable once published, so a subscriber’s original terms survive any newer plan the provider ships.
Subscription records: on-chain bindings between an agent wallet and a plan, carrying status, billing cycle, and the authorized amount.
Allowance records: on-chain spend caps for metered and one-time billing, with running totals anyone can read.

Facilitator Layer

The Facilitator is the off-chain component that does the mechanical work: it verifies payment headers and triggers settlement on-chain. During the beta, the Facilitator is a centralized service operated by Scribe Finance, a trade-off stated plainly, with a roadmap toward a permissionless Facilitator Network in which anyone who stakes collateral can operate a node.

The Facilitator also issues Payment Session tokens for high-frequency agents. A session token authorizes a burst of requests against a balance the agent commits up front; the underlying settlements are batched on-chain, driving per-request latency toward zero while preserving full on-chain auditability. Payment sessions ship with general availability.

SDK Layer

The SDK is where all of this disappears. An agent developer sending a first payment never touches x402 headers, the contracts, or a facilitator connection: install @scribefinance/sdk, construct a ScribeFinanceAgent with a wallet, and call agent.pay() or agent.subscribe().

The Agent SDK and Provider SDK references document the full API.

On-chain transparency

Because every piece of state lives on Robinhood Chain, any payment or subscription can be verified independently: no trust in Scribe Finance required. This is a deliberate design principle. Scribe Finance offers block explorer integration and an indexed event log as conveniences, but neither gates access to anything; authority stays with the chain.