> For the complete documentation index, see [llms.txt](https://whitepaper.after-bell.uk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whitepaper.after-bell.uk/protocol-overview/system-overview.md).

# System Overview

Introduces the components that deliver AFTERBELL markets and settlement.

AFTERBELL combines a browser-based market interface, an off-chain order book, on-chain settlement, and an external-data resolution process. The architecture is designed to let users trade defined Yes/No outcomes while keeping settlement and outcome tokens on Robinhood Chain.

```
User / browser
    ↓
Market interface and signed order
    ↓
Off-chain CLOB
    ↓
Order matching or USDG-backed share minting
    ↓
Robinhood Chain smart contracts
    ↓
USDG + ERC-1155 Yes/No outcome tokens
    ↓
Chainlink feed + Robinhood API cross-check
    ↓
Resolution and redemption
```

### User interface and order entry

The frontend is identified as React, viem, and wagmi. Its role is to present markets, let users choose Yes or No, and support order interaction from the browser. A user signs an order without a gas fee for that signature step.

The frontend is an off-chain component. It is part of the product experience, not an on-chain settlement mechanism.

### Off-chain order book

The proposed central limit order book runs off-chain, using Node.js and WebSocket infrastructure. It receives signed orders and matches compatible orders. This component supports trading activity, but it is not itself the settlement layer.

When an order is matched, settlement proceeds through smart contracts on Robinhood Chain. The source also allows the system to mint new paired shares from USDG rather than only matching two participants. Detailed order handling belongs in the Trading Architecture section.

### On-chain settlement and outcome tokens

Robinhood Chain is the intended blockchain environment. The source identifies Chain ID 4663, the EVM, and an FCFS mempool. On-chain components hold USDG, issue ERC-1155 outcome tokens, and settle resolved markets.

USDG is the stated settlement asset. The ERC-1155 tokens represent Yes and No outcomes for a market. At resolution, the winning outcome can be redeemed and the losing outcome has no redemption value.

The source identifies these smart-contract responsibilities at a high level:

| Component         | Intended role                                                |
| ----------------- | ------------------------------------------------------------ |
| ConditionalTokens | Outcome-token operations, including split, merge, and redeem |
| MarketFactory     | Market creation and fees                                     |
| OracleResolver    | Oracle reading, cross-checking, and the circuit breaker      |
| CTFExchange       | CLOB settlement, signed orders, and batch execution          |
| FeeCollector      | Fee collection and distribution                              |

This is an architecture map, not a full contract specification.

### Oracle and administrative boundary

The proposed resolution process uses a Chainlink Stock Token Feed as its primary source and the Robinhood REST API as a cross-check. An off-chain keeper participates in that cross-checking flow.

If source values differ by more than 5%, the market pauses. An administrator can manually resolve using off-chain evidence. Accordingly, the system should not be described as fully decentralized or completely trustless.

### What is on-chain and off-chain

**On-chain** components include smart contracts, USDG settlement, ERC-1155 outcome tokens, and market settlement.

**Off-chain** components include the CLOB matching engine, Robinhood API cross-check, keeper infrastructure, and frontend. These boundaries are material to the trust model and availability assumptions.

{% hint style="warning" %}
This is proposed architecture for a project still in development. Smart contracts are not yet audited, and the system does not claim proven production operation.
{% endhint %}


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