Skip to main content

​
Overview

The Custom Function Rule allows you to create sophisticated loyalty rules using JavaScript code. This rule type leverages Stratus functions to evaluate complex conditions, perform calculations, and determine rewards based on custom logic that goes beyond standard rule types.

​
Key Features

  • Custom Logic: Write JavaScript functions to implement any evaluation logic
  • Dynamic Rewards: Calculate variable reward amounts based on user data or conditions
  • External Data: Access external APIs and services using approved modules
  • Complex Conditions: Implement multi-step validation and conditional rewards
  • Flexible Output: Return points, badges, or multipliers based on your logic

​
Use Cases

Gamification Logic

Reward users based on complex gaming achievements, streaks, or skill levels.

Social Scoring

Calculate rewards based on social media engagement metrics or community participation.

Tiered Rewards

Implement dynamic reward structures based on user tier, activity level, or spending patterns.

Cross-Platform Integration

Combine data from multiple platforms to create unified reward systems.

​
How It Works

1

Write Your Function

Create a JavaScript function that receives user data and loyalty rule information as input.
Your function must follow the Stratus function syntax and use only approved modules.
2

Define Evaluation Logic

Implement your custom logic to determine if a user qualifies for rewards and calculate the appropriate reward amount.
3

Return Reward Details

Your function returns a structured object describing the reward to grant (points, badges, or multipliers).
4

Automatic Execution

The platform automatically executes your function when users attempt to complete the rule.

​
Function Requirements

Your custom function must:
  • Accept (input, output) parameters
  • Parse the input data containing user and rule information
  • Call output.setResult([rewardObject]) with your reward details
  • Return output.buildOutput()
  • Use only approved modules: axios, lodash, viem, and viem/chains
Functions that don’t follow the required syntax or use unauthorized modules will fail validation.

​
Input Data Structure

Your function receives the following input structure: 
{
  user: {
    id: string,
    walletAddress: string,
    walletType: string
  },
  loyaltyRule: {
    id: string,
    name: string,
    type: string,
    amount: number,
    metadata: object,
    startTime: string,
    endTime: string,
    interval: string,
    rewardType: string
  }
}

​
Output Requirements

Your function must return an array with a single reward object containing:
  • walletAddress: The user’s wallet address to reward
  • amount: Points to grant (for fixed point rewards)
  • idempotencyKey: Unique identifier to prevent duplicate rewards
  • data: Optional JSON string with additional context (max 1KB)
  • loyaltyBadgeId: Optional badge to award instead of points
  • loyaltyMultiplierAmount: Optional multiplier for range-based rules

​
Example Use Cases

​
Dynamic Point Calculation

// Calculate points based on user's social media followers
const followerCount = await getFollowerCount(user.socialId)
const basePoints = 10
const bonusPoints = Math.floor(followerCount / 1000) * 5
const totalPoints = basePoints + bonusPoints

output.setResult([
  {
    walletAddress: user.walletAddress,
    amount: totalPoints,
    idempotencyKey: `social-bonus-${user.id}-${Date.now()}`,
    data: JSON.stringify({ followerCount, bonusPoints }),
  },
])

​
Conditional Badge Award

// Award special badge for high-value users
const userValue = await calculateUserValue(user.id)
const isHighValue = userValue > 1000

if (isHighValue) {
  output.setResult([
    {
      walletAddress: user.walletAddress,
      loyaltyBadgeId: 'high-value-user-badge-id',
      idempotencyKey: `high-value-${user.id}`,
    },
  ])
}

​
Getting Started

1

Learn Function Syntax

Read the Stratus Function Syntax guide to understand the required export patterns and validation rules.
2

Write Your Function

Follow the Function Loyalty Rule Guide for a complete tutorial on creating custom loyalty rule functions.
3

Test Your Function

Use the function editor in the loyalty rule form to write and test your custom logic.
4

Deploy and Monitor

Save your rule and monitor function execution through the admin dashboard.

​
Best Practices

Keep functions simple and focused - Complex logic should be broken into smaller, testable functions.
Handle errors gracefully - Always include try-catch blocks and meaningful error messages.
Use idempotency keys - Ensure your functions can be safely retried without creating duplicate rewards.
Optimize for performance - Minimize external API calls and use efficient data structures.

​
Troubleshooting

  • Ensure your function follows the exact syntax requirements
  • Check that you’re only using approved modules
  • Verify your output structure matches the required format
  • Review function logs for specific error messages - Test your function with sample data before deploying - Ensure all external dependencies are available
  • Optimize external API calls and database queries
  • Consider caching frequently accessed data
  • Monitor function execution time and memory usage
⌘I