Fees

Fees in TrexWallet are charges applied to transactions to cover operational costs, incentivize network validators, or generate platform revenue. The fee system is fully configurable through the tariff grid.

Fee Components

Every transaction fee consists of up to three components:

Component	Source	Example
Percent fee	Configured in tariff	0.5% of 1000 USDT = 5.00 USDT
Fixed fee	Configured in tariff	Flat 1.00 USDT per transaction
Network fee	Dynamic from blockchain	Ethereum gas: ~0.001 ETH

Total fee = amount × percent_fee + fixed_fee + network_fee

Network Fees

Network fees are dynamic — they reflect the current cost of broadcasting a transaction on the blockchain. TrexWallet's blockchain scanners continuously monitor network conditions and update fee estimates.

• Ethereum/ERC-20: Gas price × gas limit (varies with network congestion)
• Tron/TRC-20: Energy/bandwidth fees (generally lower than Ethereum)
• Bitcoin: Fee per byte (depends on mempool size)
• TON: Fixed low fees

Network fees are only charged when the UseNetFee flag is set in the matching tariff.

Commission Wallets

Collected fees are directed to designated system wallets:

Wallet	Purpose
Commission Wallet (-104)	General commission collection
Commission Exchange (-102)	Exchange operation fees
Commission Swap (-101)	Swap operation fees
Commission Withdrawal (-103)	Withdrawal fees

Fee Calculation Flow

sequenceDiagram
    participant User
    participant TrexWallet
    participant Tariff Engine
    participant Blockchain

    User->>TrexWallet: Initiate transaction
    TrexWallet->>Tariff Engine: Find matching tariff (multi-dimensional)
    Tariff Engine-->>TrexWallet: Tariff found (percent, fixed, flags)
    alt UseNetFee flag set
        TrexWallet->>Blockchain: Get current network fee
        Blockchain-->>TrexWallet: Network fee estimate
    end
    TrexWallet-->>User: Show total fee preview
    User->>TrexWallet: Confirm
    TrexWallet->>TrexWallet: Deduct fee + execute

Fee Preview API

Check the exact fee before executing a transaction:

GET /trex/v1/estimate_fee
  ?tx_type=Outcome
  &currency=USDT
  &amount=500
  &network_from=2

Response (strings to preserve precision):

{
  "result": {
    "fee": "3.50",
    "percentFee": "0.005",
    "fixedFee": "1.00",
    "minAmount": "10.00",
    "maxAmount": "100000.00",
    "tag": "Standard Withdrawal"
  },
  "error": null
}

The endpoint uses the same tariff matcher as production. For exchange/swap requests add to_currency. For payment-order estimates pass app_id and network_to (the terminal id) so the per-merchant / per-terminal tariff wins.

When Fees Are Applied

Operation	Fee Timing	Fee Type
Internal transfer	At execution	Usually free (percent=0, fixed=0)
Withdrawal	At confirmation	Percent + fixed + network
Exchange order	At matching	Percent per side
Swap	At execution	Percent on pair
Payment order	At completion	Percent + fixed (merchant tariff)
Investment yield	At distribution	Percent (management fee)

Special Scenarios

Exchange Operations

Exchange uses two tariffs — one for each side of the trade. A BTC/USDT exchange applies the BTC tariff to the seller and the USDT tariff to the buyer.

Payment Spread

For payment gateway operations, an additional payment_spread can be configured per currency. This FX markup is applied on top of the exchange rate for cross-currency operations and always favors the platform:

• Incoming payment orders: rate = mid × (1 + payment_spread) on the payment currency — the buyer pays a bit more.
• Outgoing transfer orders (payouts): rate = mid × (1 − payment_spread) on the terminal currency — the recipient receives a bit less (or, when the payout amount is fixed, the merchant is debited a bit more).

The same per-currency coefficient is reused for both directions; payment_spread = 0 means the mid-rate with no markup.

Zero Fees

Tariffs with zero percent and zero fixed fee are valid. Internal transfers are typically configured this way. Zero-fee transactions are logged for audit purposes.

Related

• Tariffs Admin — configure fee rules and test with simulator
• Transaction States — when fees are reserved and finalized
• Sub-Balances — how fees affect balance partitions