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Doss calculates fees and enforces amount limits at the intersection of three dimensions: currency, payment method, and transaction type. Every combination can have its own fixed charge, percentage charge, minimum amount, and maximum amount.

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Data model

Fee and limit settings are stored in the fees_limits table, represented by the FeesLimit model:
fees_limits table columns
currency_id         // FK → currencies
transaction_type_id // FK → transaction_types
payment_method_id   // FK → payment_methods (null for non-payment-method types)
charge_percentage   // percentage fee (e.g. 1.5 for 1.5%)
charge_fixed        // flat fee in the currency's unit
min_limit           // minimum transaction amount (defaults to 1.00)
max_limit           // maximum transaction amount (null = unlimited)
processing_time     // informational processing time
has_transaction     // 'Yes' | 'No' — whether transactions exist for this rule

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Transaction types

Fees and limits are configured independently for each transaction type:
Tab in UIInternal nameRequires payment method
depositDepositYes
withdrawalWithdrawalYes
transferTransferredNo
exchangeExchange_FromNo
request_paymentRequest_ReceivedNo
For deposit and withdrawal types, a separate fee record exists for every active payment method. For transfer, exchange, and request payment, a single record covers the entire transaction type. Fees and limits are configured per currency. Start at Settings > Currencies (/admin/settings/currency), then open a currency’s settings. The fees/limits page URL follows this pattern: 
/admin/settings/feeslimit/{tab}/{currency_id}
For example, to set deposit fees for currency ID 1: 
/admin/settings/feeslimit/deposit/1
Valid tab values: deposit, withdrawal, transfer, exchange, request_payment

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How fees are calculated

For each transaction, Doss applies both fee components: 
total_fee = charge_fixed + (transaction_amount × charge_percentage / 100)
Both components can be set to 0 independently. Setting charge_fixed = 0 and charge_percentage = 0 makes the transaction free.

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Configuring deposit and withdrawal fees

Deposit and withdrawal fees are set per payment method. The form lists every active payment method available for the currency type (fiat or crypto), loaded from the platform-wide payment method settings.
1

Open the fee settings

Go to /admin/settings/feeslimit/deposit/{currency_id} or /admin/settings/feeslimit/withdrawal/{currency_id}.
2

Fill in values for each payment method

For each listed payment method, set:
  • Charge percentage — percentage fee applied to the transaction amount
  • Charge fixed — flat fee charged per transaction
  • Min limit — minimum allowed transaction amount (cannot be blank; defaults to 1.00)
  • Max limit — maximum allowed transaction amount (leave blank for no upper limit)
  • Has transaction — whether this payment method should be active for live transactions
3

Save

POST to /admin/settings/feeslimit/update-deposit-limit. The system upserts a FeesLimit record per payment method.
For the default currency, has_transaction is automatically set to Yes regardless of the checkbox value.

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Configuring transfer, exchange, and request payment fees

These transaction types use a single fee record per currency (no payment method dimension).
1

Open the fee settings

Go to /admin/settings/feeslimit/transfer/{currency_id}, /admin/settings/feeslimit/exchange/{currency_id}, or /admin/settings/feeslimit/request_payment/{currency_id}.
2

Fill in the values

Set charge percentage, charge fixed, min limit, and max limit for the currency.
3

Save

POST to /admin/settings/feeslimit/update-deposit-limit. The system upserts a single FeesLimit record keyed on (transaction_type_id, currency_id).

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Fiat vs crypto settings

The available payment methods shown in the fee configuration form differ by currency type:
  • Fiat currencies — payment methods drawn from getPaymoneySettings('payment_methods')['web']['fiat']['deposit'] (or ['withdrawal'])
  • Crypto currencies — payment methods drawn from getPaymoneySettings('payment_methods')['web']['crypto']['deposit'] (or ['withdrawal'])
Decimal precision for amount display also differs: fiat uses the decimal_format_amount preference (typically 2), while crypto uses decimal_format_amount_crypto (typically 8).

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Per-merchant-group fee overrides

Merchant groups allow per-group fee customisation. When a merchant’s group changes, fees can be adjusted automatically. Navigate to Settings > Merchant groups (/admin/settings/merchant-group) to create and edit groups, then use the POST /admin/merchants/change-fee-with-group-change endpoint to apply the group’s fee rules to the merchant.

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Fetching fee details via AJAX

Two AJAX endpoints support the fee settings UI:
EndpointPurpose
POST /admin/settings/get-feeslimit-detailsRetrieve current fee records for a currency + transaction type
POST /admin/settings/get-specific-currency-detailsRetrieve currency details along with its fee records
Both return a JSON payload with status (200 on success, 401 if not found) and the feeslimit data.

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