Universal Payment & Merchant Query Directory

Every electronic payment is partitioned across three distinct entities: the Issuing Bank Interchange (0.3%–1.9%), the Card Network Assessment (Visa/Mastercard ~0.14%), and the Payment Facilitator Markup (Stripe/PayPal ~0.8%–1.5%). Blended flat rates obscure this spread, while interchange-plus models pass through true wholesale costs.

When passing transaction costs to the buyer, simple addition (Net + Fee) causes mathematical margin shortfall because the gateway taxes the fee itself. The correct inverted equation is: Gross Invoice = (Target Net + Fixed Fee) / (1 - Variable Rate)

MoR platforms like Polar.sh and Paddle absorb sales tax compliance, remittance, and filing liabilities across 100+ jurisdictions. While flat 5.0% MoR fees can be expensive, Polar's 3.8% tier introduces a breakeven tipping point at $1,379 MRR over Lemon Squeezy, significantly reducing SaaS overhead.

Physical card terminals experience substantially lower fraud risk than web checkouts. As a result, Square (2.6% + 10¢), Clover (2.3% + 10¢), and Zettle (1.75% UK) offer significantly reduced rates for tapped/dipped cards compared to 2.9% + 30¢ e-commerce gates.