Market Contracts

This guide explains how to write, deploy, and integrate a smart contract that governs storage deals in the Market 2.0 architecture. Contracts are responsible for determining whether a deal is valid and returning a DealID.

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🎯 Purpose of the Contract

In Market 2.0, contracts are used to:

• Accept or reject deals

• Optionally implement additional business logic (e.g. FIL+ validation, payments, approvals)

• Return a DealID string if accepted

The contract does not manage storage or retrieval itself—that is handled by the SP.

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✅ Requirements

A valid Market 2.0 contract must:

1. Be deployed on a supported chain (e.g. Filecoin EVM, Hyperspace, etc)

2. Be whitelisted by the storage provider (via UI or admin tool)

3. Have its ABI uploaded

4. Expose a method that:

   • Accepts a single bytes input

   • Returns a string (representing the DealID)

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🔁 Flow

1. Client encodes parameters for your method

2. Client submits deal to Curio with:

   • Contract address

   • Method name

   • ABI-encoded parameters

3. Curio:

   • Loads ABI

   • Packs the method call

   • Calls eth_call

   • Unpacks the return value

If the method returns a string → deal is accepted. If empty string or call fails → deal is rejected.

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🧪 Example Contract Method

function verifyDeal(bytes calldata params) external view returns (string memory) {
    // decode params into your structure
    // perform validation
    // return deal ID if valid
    return "deal-123";
}

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📜 ABI Upload

The SP must upload the ABI JSON for your contract when whitelisting it:

• This enables Curio to find and call the method

• ABI must include the method name, inputs, and return types

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🔐 Client Responsibilities

Clients must:

• Choose a contract accepted by the SP

• Encode call parameters into []byte

• Provide method name and contract address in the deal

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🧩 Products and Contract Use

Contracts are typically used from within a product (e.g. ddov1). The product defines:

• Contract address

• Method name

• Encoded params (using ABI rules)

This decouples contract logic from storage logic and keeps deals composable.

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🚫 Common Errors

Error	Cause
426 Deal rejected by contract	Returned string is empty or eth_call fails
ABI not found	Contract not whitelisted or ABI missing
Invalid method	Method name not found in ABI
Incorrect input format	Method doesn’t accept single bytes parameter

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✅ Checklist for Integration

• Deploy contract on supported chain

• Expose a function(bytes) returns (string) method

• Whitelist contract via SP UI

• Upload ABI including the method

• Coordinate with clients on method + param encoding

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This guide enables market developers to plug in custom contract logic without requiring any changes to Curio or the storage pipeline.

Welcome to programmable storage governance.