Who charges payment-processing fees, and how should they be budgeted?

Payment-processing fees are charged by the payment institution, acquirer, or contracted partner under the merchant's approved terms; they are not a standard income item for the software developer. Wavesteam separates product integration from every transaction charge. Domestic and international rates must be modelled by merchant country, business category, payment method, card origin, currency, and settlement—not one global percentage.

There are two ledgers. Engineering covers payment integration, order states, refunds, split settlement, reconciliation, and risk controls. The channel ledger covers charges incurred by transactions. Combining them makes it impossible to explain a rate change or reconcile after changing developers. The merchant should normally own the payment account; the quotation should separate Wavesteam's service, the provider's channel fees, and any aggregator markup.

When defining budget, scope, and cost assumptions, also compare How are parcel tracking APIs usually priced? and How is the App Store commission calculated, and which costs does it affect?; the linked guidance adds context that should be considered in the same decision.

A merchant bill can contain a percentage, a fixed amount per transaction, cross-border and currency-conversion additions, dispute or chargeback fees, and payout charges. Some providers bundle acquiring and card-network costs; an aggregator may add a technical fee. The precise question is therefore not “what does Visa charge?” but “what terms were approved for this merchant and product?”

WeChat Pay's onboarding guide currently describes application as free and gives 0.6%–1% of transaction value as a usual merchant-service reference, depending on business category. Its agreement makes the approved record controlling and promotional terms subject to expiry or change. Alipay likewise directs merchants to the product and rate displayed for their agreement. These support initial screening, not a permanent rate for all mainland payments.

International examples are storefront-specific. Stripe's US standard pricing lists a domestic-card rate and separate additions for international cards and currency conversion. PayPal's US business fees vary by Checkout product, funding method, cross-border treatment, and fixed-fee currency. Neither is a worldwide rate.

For a low-value order, the fixed component can dominate margin. Cross-border transactions may combine international-card and conversion cost. Model successful-value percentage + fixed fee per successful transaction + conversion/cross-border additions + disputes and chargebacks + aggregator or optional services. Confirm whether refunds return the original fee and include payout timing as a working-capital cost.

Wavesteam applies candidate terms to the order-value distribution, not only the average order. We model payment methods, refunds, card origin, and currency with conservative, expected, and favourable scenarios when history is unavailable. The result shows processing cost as a percentage of revenue and gross margin, net proceeds per order, chargeback loss, and settlement timing.

Delivery maps each payment product to its merchant ID, approved-rate evidence, invoice fields, reconciliation columns, and exception owner. Acceptance covers success, failure, closure, refund, and duplicate notification in sandbox and small live transactions; finance samples provider statements, platform orders, and bank settlement. Rates were reviewed on August 25, 2026 and must be rechecked in the target market's current agreement before launch.