Jb Pay Hook

Juicebox V5 Pay Hook Generator

Generate custom pay hooks for Juicebox V5 projects based on natural language specifications.

Before Writing Custom Code

Always evaluate if an off-the-shelf solution fits the user's needs:

If off-the-shelf solutions fit, guide the user to deploy them instead of generating custom code.

V5 Pay Hook Architecture

Pay hooks in V5 follow a two-stage pattern:

Stage 1: Data Hook (beforePayRecordedWith)

• Receives payment info before recording
• Returns adjusted weight and hook specifications
• Implements IJBRulesetDataHook

Stage 2: Pay Hook (afterPayRecordedWith)

• Executes after payment is recorded
• Receives forwarded funds and context
• Implements IJBPayHook

A contract can implement both interfaces (like the buyback hook) or just the pay hook.

JBAfterPayRecordedContext Fields

struct JBAfterPayRecordedContext {
    address payer;                  // Payment originator
    uint256 projectId;              // Project being paid
    uint256 rulesetId;              // Current ruleset ID
    JBTokenAmount amount;           // Payment amount
    JBTokenAmount forwardedAmount;  // Amount forwarded to hook
    uint256 weight;                 // Token minting weight
    uint256 newlyIssuedTokenCount;  // Tokens minted
    address beneficiary;            // Token recipient
    bytes hookMetadata;             // Data from data hook
    bytes payerMetadata;            // Data from payer
}

Design Patterns

Simple Pay Hook (afterPayRecordedWith only)

Use when you only need to execute logic after payment without modifying minting behavior.

contract SimplePayHook is IJBPayHook, ERC165 {
    function afterPayRecordedWith(JBAfterPayRecordedContext calldata context) external payable {
        // Validate caller is a project terminal
        // Execute custom logic
    }

    function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
        return interfaceId == type(IJBPayHook).interfaceId || super.supportsInterface(interfaceId);
    }
}

Data Hook + Pay Hook (full control)

Use when you need to modify weight, intercept funds, or control hook routing.

contract FullPayHook is IJBRulesetDataHook, IJBPayHook, ERC165 {
    function beforePayRecordedWith(JBBeforePayRecordedContext calldata context)
        external view returns (uint256 weight, JBPayHookSpecification[] memory hookSpecifications)
    {
        // Analyze payment, determine routing
        // Return weight and hook specs
    }

    function afterPayRecordedWith(JBAfterPayRecordedContext calldata context) external payable {
        // Execute with forwarded funds
    }

    function beforeCashOutRecordedWith(JBBeforeCashOutRecordedContext calldata context)
        external view returns (uint256, uint256, uint256, JBCashOutHookSpecification[] memory)
    {
        // Pass through if not handling cash outs
        return (context.ruleset.cashOutTaxRate, context.cashOutCount, context.totalSupply, new JBCashOutHookSpecification[](0));
    }

    function hasMintPermissionFor(uint256) external pure returns (bool) {
        return false; // Only true if hook needs to mint
    }
}

Contract-as-Owner Pattern

Use when the project needs to be autonomous with structured rules and delegated permissions.

Reference: revnet-core-v5 (REVDeployer)

• Contract owns the Juicebox project NFT
• Implements hooks and controls project configuration
• Delegates authority via JBPermissions

Generation Guidelines

1. Ask clarifying questions about the desired behavior
2. Evaluate off-the-shelf options first
3. Choose the simplest pattern that meets requirements
4. Include terminal validation in afterPayRecordedWith
5. Generate Foundry tests with fork testing against deployed contracts
6. Use correct V5 terminology (ruleset, cash out, weight, reserved rate)

Example Prompts

• "Create a pay hook that mints a custom ERC20 token proportional to payments"
• "I want to reward payers with points based on payment amount"
• "Build a hook that routes 10% of payments to a charity address"
• "Create an autonomous project that caps individual payment amounts"

Reference Implementations

• nana-buyback-hook-v5: https://github.com/Bananapus/nana-buyback-hook-v5
• nana-721-hook-v5: https://github.com/Bananapus/nana-721-hook-v5
• revnet-core-v5: https://github.com/rev-net/revnet-core-v5

Output Format

Generate:

1. Main contract in src/
2. Interface in src/interfaces/ if needed
3. Test file in test/
4. Deployment script in script/ if requested

Use Foundry project structure with forge-std.