hizi docs

Appearance

Buy-Features ​

Buy-features allow players to purchase direct entry into a bonus feature (e.g., free spins) for a fixed price, bypassing the base game trigger.

How It Works ​

Buy-features are explicitly configured per game. The engine configuration specifies which features can be purchased, referencing the feature entries. At startup, the engine calculates:

  • The buy price (calculated so buy-feature RTP matches total game RTP)
  • Expected spin count including retriggers

Getting Available Buy-Features ​

Buy-features are included in the loadConfig response:

typescript
const response = await loadConfig({ backendURL, token: sessionToken });
if (response.success) {
  const buyFeatures = response.result.config.buyFeatures;

  if (buyFeatures?.length > 0) {
    for (const feature of buyFeatures) {
      console.log(`Feature: ${feature.id}`);
      console.log(`  Price: ${feature.price}x stake`);
      console.log(`  Initial spins: ${feature.initialSpins}`);
    }
  }
}

Buy-Feature Option Type ​

Each entry in config.buyFeatures is IBuyFeatureOption & { id: string }:

typescript
// Base type
interface IBuyFeatureOption {
  feature: string; // Feature name referencing the feature entries
  price: number; // Buy price as multiplier of stake
  featureRTP: number; // Feature RTP percentage
  initialSpins: number; // Spins awarded on initial trigger
}

// In config.buyFeatures, each entry also has an `id` field:
// (IBuyFeatureOption & { id: string })[]
FieldTypeDescription
idstringFeature identifier
featurestringFeature name that maps to the feature entries in the engine configuration
pricenumberBuy price as a multiplier of stake. A price of 100 means the feature costs 100x the stake amount
featureRTPnumberThe expected return percentage when buying this feature
initialSpinsnumberNumber of spins awarded on initial trigger (before retriggers)

Purchasing a Feature ​

To buy a feature, call placeBet with featureToBuy. The engine computes the price from the stake and the configured price multiplier, so clients only need to pass the feature ID:

typescript
const feature = buyFeatures[0]; // e.g. { id: 'freespin', price: 100 }
const currentStake = config.stakes[selectedStakeIndex];

const response = await placeBet({
  backendURL,
  token: sessionToken,
  stake: currentStake,
  featureToBuy: feature.id,
});

if (response.success) {
  const gameResult = response.result.result;

  // You're now in the feature - handle like any multi-step round
  if (gameResult.engineData.inProgress) {
    // Continue with placeBet({ backendURL, token: sessionToken })
  }
}

TIP

feature.price is a multiplier of stake — use it for UI display (feature.price * currentStake) when you need to show the total cost. You do not need to pass it back to the engine.

Next Steps ​