PAR Sheets

A PAR sheet (Probability Accounting Report) is the mathematical blueprint for a slot game. It defines every possible symbol combination, its probability of occurring, and the payout for that combination. KINGSTONE uses PAR sheets to pre-compute outcome queues — the sequences of results that players receive when they spin.

Before you can register a game or execute spins, you need to upload at least one PAR sheet.

What a PAR Sheet Contains

A PAR sheet defines:

• Game metadata — title, manufacturer, number of reels, denomination
• Symbols — the icons that appear on each reel (e.g., Seven, Bar, Cherry)
• Prize tiers — groups of outcomes ranked by value (T0 = no win, T1-T6 = winning tiers)
• Combinations — every possible reel outcome with its probability, payout multiplier, and tier assignment
• Certified RTP — the expected Return-to-Player percentage (e.g., 92.5%)

PAR Sheet JSON Format

The upload endpoint accepts a JSON object with this structure:

{
  "gameTitle": "Sandbox Classic 3-Reel",
  "manufacturer": "Partner Test Studio",
  "numReels": 3,
  "virtualStopsPerReel": [32, 32, 32],
  "certifiedRtp": 0.925,
  "denominationUsd": 0.25,
  "symbols": [
    { "name": "Seven", "display": "7" },
    { "name": "Bar", "display": "BAR" },
    { "name": "Cherry", "display": "CH" },
    { "name": "Plum", "display": "PL" },
    { "name": "Blank", "display": "BL" }
  ],
  "tiers": [
    { "tierId": 0, "name": "No Win", "probability": 0.7, "payMultiplier": 0 },
    { "tierId": 1, "name": "Small Win", "probability": 0.15, "payMultiplier": 2 },
    { "tierId": 2, "name": "Medium Win", "probability": 0.08, "payMultiplier": 3 },
    { "tierId": 3, "name": "Large Win", "probability": 0.04, "payMultiplier": 4 },
    { "tierId": 4, "name": "Big Win", "probability": 0.02, "payMultiplier": 5 },
    { "tierId": 5, "name": "Huge Win", "probability": 0.008, "payMultiplier": 6 },
    { "tierId": 6, "name": "Jackpot", "probability": 0.002, "payMultiplier": 38.5 }
  ],
  "combinations": [
    {
      "reelSymbols": ["Blank", "Blank", "Blank"],
      "comboString": "BL|BL|BL",
      "payMultiplier": 0,
      "comboProbability": 0.7,
      "tierId": 0,
      "displayWeight": 1
    },
    {
      "reelSymbols": ["Seven", "Seven", "Seven"],
      "comboString": "7|7|7",
      "payMultiplier": 38.5,
      "comboProbability": 0.002,
      "tierId": 6,
      "displayWeight": 1
    }
  ]
}

A complete sample PAR sheet is available in the SDK repository at examples/sample-par-sheet.json.

Validation Rules

When you upload a PAR sheet, KINGSTONE validates the math:

• Tier probabilities must sum to 1.0. The total probability across all tiers must equal exactly 1.0 (within floating-point tolerance).
• Combination probabilities must match tier probabilities. The sum of comboProbability for all combinations in a tier must equal that tier's probability.
• Certified RTP must match. The computed RTP (sum of probability times pay multiplier across all combinations) must match the declared certifiedRtp.
• Symbol references must be valid. Every symbol name in combinations[].reelSymbols must match a symbol defined in the symbols array.
• Tier IDs must be valid. Every tierId in combinations must reference a tier defined in the tiers array.
• Reel count must be consistent. The length of virtualStopsPerReel and every reelSymbols array must equal numReels.

If any validation fails, the API returns an error with details about what went wrong.

Uploading a PAR Sheet

With the SDK

import { KingstoneClient } from '@kingstone/sdk';
import parSheetData from './sample-par-sheet.json';

const client = new KingstoneClient({
  apiKey: 'ks_sandbox_your_key_here',
  sandbox: true,
});

const result = await client.uploadParSheet(parSheetData);

console.log(`PAR sheet created: ID ${result.parSheetId}`);
console.log(`  Game: ${result.gameTitle}`);
console.log(`  Reels: ${result.numReels}`);
console.log(`  RTP: ${(result.certifiedRtp * 100).toFixed(2)}%`);
console.log(`  Symbols: ${result.symbolCount}`);
console.log(`  Tiers: ${result.tierCount}`);
console.log(`  Combinations: ${result.combinationCount}`);

With curl

curl -X POST https://sandbox.kingstone.dev/api/partner/v1/par-sheets \
  -H "X-API-Key: ks_sandbox_your_key_here" \
  -H "Content-Type: application/json" \
  -d @sample-par-sheet.json

Listing PAR Sheets

After uploading, you can list all your active PAR sheets:

const { parSheets } = await client.listParSheets();

for (const sheet of parSheets) {
  console.log(`${sheet.parSheetId}: ${sheet.gameTitle} (${sheet.numReels}-reel, RTP ${(sheet.certifiedRtp * 100).toFixed(2)}%)`);
}

Next Steps

Once you have uploaded a PAR sheet, register a game to link it to a playable configuration with wager limits.