Gas Tank

The Gas Tank is MakaPay's unified gas management system that allows merchants to fund payment settlements across all supported blockchains from a single USDT balance on MakaChain.

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How It Works

The Problem

Traditional multi-chain payment acceptance requires:

• ETH on Ethereum for gas

• MATIC on Polygon for gas

• BNB on BSC for gas

• Managing multiple wallets and balances

This leads to:

• Idle capital sitting unused on each chain

• Complexity managing multiple native tokens

• Risk of settlements failing due to insufficient gas

The Solution

MakaPay's Gas Tank:

• Single deposit of USDT on MakaChain

• Automatic deduction when payments are settled

• Works across Ethereum, Polygon, BSC, and MakaChain

┌─────────────────────────────────────────────┐
│         Your Gas Tank (MakaChain)           │
│         Balance: 50.00 USDT                 │
└─────────────────────────────────────────────┘
                     │
    ┌────────────────┼────────────────┐
    ▼                ▼                ▼
┌─────────┐    ┌─────────┐    ┌─────────┐
│Ethereum │    │ Polygon │    │   BSC   │
│Settlement│   │Settlement│   │Settlement│
│Gas: $2.50│   │Gas: $0.03│   │Gas: $0.10│
└─────────┘    └─────────┘    └─────────┘

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When Gas Tank Is Used

The Gas Tank is used when both conditions are true:

1. gasless: false (default)

2. payerCoversFee: false (default)

Fee Deduction Breakdown

When a payment is settled, the following are deducted from your Gas Tank:

Fee Component	Description
Platform Fee	Percentage based on your plan tier (0% - 1%)
Processing Fee	Fixed $0.10 per transaction
Gas Fee	Blockchain gas cost in USD equivalent

Example: $100 Payment on Polygon (Free Plan)

Payment received: $100 USDT
Customer sent to: 0x... (payment wallet address)

Settlement:
├── Platform Fee (1%):    $1.00 → Deducted from Gas Tank
├── Processing Fee:       $0.10 → Deducted from Gas Tank
├── Gas Fee (Polygon):    $0.03 → Deducted from Gas Tank
└── Total Gas Tank Deduction: $1.13

Merchant receives: $100.00 USDT (full amount)

When Gas Tank Is NOT Used

Gas Tank is bypassed when:

• gasless: true - Fees taken from payment amount on-chain

• payerCoversFee: true - Fees added on top, taken on-chain

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Depositing to Gas Tank

Step 1: Get Your Deposit Address

1. Navigate to Dashboard > Gas Tank

2. Click Deposit or Get Deposit Address

3. A unique deposit address is generated for you

Step 2: Send USDT

Send USDT to your deposit address on MakaChain:

• Network: MakaChain (Chain ID: 777178)

• Token: USDT (0x30C28E393E0732335235685B345c95E6465Ad8A5)

• RPC: https://rpc.makachain.io

Step 3: Automatic Credit

Once confirmed:

• Your Gas Tank balance updates automatically

• No manual claiming required

• Funds available immediately for settlements

How Deposits Work (Technical)

1. A deterministic address is computed using CREATE2

2. You send USDT to this pre-computed address

3. MakaPay deploys a PaymentWallet at that exact address

4. The wallet forwards USDT to the GasTank contract

5. GasTank credits your user balance

// GasTank.sol
function onPaymentReceived(
    string calldata orderId,    // "userId_timestamp"
    address token,
    uint256 amountReceived,
    uint256 originalAmount,
    bool isPaymentComplete
) external {
    // Parse userId from orderId
    string memory parsedUserId = parseUserId(orderId);

    // Credit user balance
    userBalances[parsedUserId] += amountReceived;

    emit Deposited(parsedUserId, amountReceived);
}

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Gas Tank Contract

The GasTank is a smart contract deployed on MakaChain that manages merchant balances.

Contract Address

Network	Address
MakaChain Mainnet	0x... (see dashboard)
MakaChain Testnet	0x... (see dashboard)

Key Functions

getBalance(userId)

Returns the current USDT balance for a user.

function getBalance(string calldata userId) external view returns (uint256)

deductGas(userId, amount)

Deducts USDT from a user's balance (called during settlement).

function deductGas(string calldata userId, uint256 usdtAmount) external onlyOwner

batchDeductGas(userIds, amounts)

Efficiently deducts from multiple users in a single transaction.

function batchDeductGas(
    string[] calldata userIds,
    uint256[] calldata amounts
) external onlyOwner

Events

event Deposited(string indexed userId, uint256 amount);
event GasDeducted(string indexed userId, uint256 amount);
event Withdrawn(string indexed userId, uint256 amount, address recipient);

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Balance Management

Checking Your Balance

Dashboard: Gas Tank page shows current balance

API:

curl https://app.makapay.com/api/balance \
  -H "Authorization: Bearer YOUR_API_KEY"

Response:

{
  "balance": "45.320000"
}

Recommended Balance

Monthly Payments	Recommended Balance
1-50	$10 - $20
50-200	$20 - $50
200-500	$50 - $100
500+	$100+

Low Balance Handling

When your Gas Tank runs low:

1. Warning: Dashboard shows low balance alert at $5

2. Awaiting Gas: Payments show "Awaiting Gas" status

3. Auto-Resume: Settlement resumes after you deposit

4. No Lost Payments: Payments are never lost, just delayed

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Gas Tank vs Gasless Mode

Feature	Gas Tank	Gasless Mode
Fee Source	Your Gas Tank balance	Payment amount
Deposit Required	Yes (USDT on MakaChain)	No
Merchant Receives	Full payment amount	Payment minus fees
Best For	Premium UX, you absorb fees	No upfront capital needed

When to Use Gas Tank

• You want customers to pay exact prices

• You have capital for deposits

• You process high-volume payments

• You want predictable merchant receipts

When to Use Gasless

• You don't want to manage deposits

• You're testing the platform

• Customers are willing to pay fees

• You prefer deducting fees from payments

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Withdrawing from Gas Tank

In most cases, you don't need to withdraw - the balance is used for settlements.

If you need to withdraw unused funds:

1. Contact support with withdrawal request

2. Specify amount and destination address

3. Withdrawal processed within 24-48 hours

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Security

Deposit Address Security

• Each user has unique deposit addresses

• Addresses are deterministic (CREATE2)

• Nonce validation prevents replay attacks

Balance Security

• Balances stored in audited smart contract

• Only MakaPay operator can deduct for settlements

• Emergency withdrawal function for edge cases

Best Practices

• Only deposit what you need for 1-2 weeks

• Monitor balance regularly

• Set up low balance alerts