Choosing a payment processor in 2026 is no longer just about accepting contactless taps; it is about selecting the operational engine of your retail or service business. While legacy leaders like SumUp and Zettle by PayPal dominate with pay-as-you-go mPOS models, aggressive disruptors like Flatpay are reshaping the market with zero-subscription flat-rate models, included hardware kits, and 24/7 dedicated support.
This deep-dive guide breaks down everything each provider does, their exact fee structures, hardware lineups, software capabilities, and hidden costs to help you make the right choice for your store or service.
1. Quick Feature & Cost Matrix
| Feature / Metric | Flatpay | SumUp | Zettle by PayPal |
| Best For | Established brick-and-mortar stores & high-volume retail | Micro-merchants, mobile services, food trucks & pop-ups | Multi-channel retailers, cafes & heavy PayPal users |
| In-Person Card Rates | 0.99% – 1.49% flat (Custom <0.99% above €200k/yr) | 1.69% – 1.75% standard (0.99% on custom/sub tiers) | 1.69% – 1.75% flat card-present rate |
| Monthly Subscription | €0 (No monthly software/hardware maintenance fees) | €0 standard (Optional SumUp One / POS Pro tiers) | €0 base app fee (Paid partner modules optional) |
| Hardware Offered | PAX A920Pro smart terminals, Lenovo tablets, thermal printers | SumUp Air, Solo, Solo + Printer, POS Lite | Zettle Reader 2, Zettle Terminal (4G/printer), iPad stands |
| Payout Speed | Daily automated payouts included | 1–3 business days (Same-day with SumUp Business Account) | 1–2 business days (Instant to PayPal Business Wallet) |
| Online Payments | Web gateway (0.99% EU cards, 1.99% international), MobilePay | Online store builder, payment links, virtual terminal | Payment links, PayPal checkout, store sync |
| Customer Support | 24/7 Phone & Email + physical on-site installation | Phone & Email (Mon–Fri 8am–7pm, Sat 8am–5pm) | Phone & Email (Mon–Fri 9am–5pm) |
2. Everything Each Provider Does
Flatpay: The All-In-One Flat-Rate Disruptor
Founded in Copenhagen, Flatpay eliminates complex interchange-plus rates, unpredictable card-type surcharges, and monthly maintenance costs.
Fixed Flat-Rate Processing: Charges a straightforward 0.99% to 1.49% per transaction regardless of card type (Visa, Mastercard, corporate, or debit cards). Custom sub-1% pricing is negotiated for businesses turning over more than €200,000 annually.
Complete Hardware Bundles: Packages include PAX A920Pro Android smart terminals, tablet displays, charging docks, thermal receipt printers, and built-in 4G SIM cards.
White-Glove Onsite Setup: Flatpay sends representatives to install hardware physically, configure software, and train staff on-site—eliminating complex self-onboarding.
Full Point-of-Sale Software: Handles sale execution, full or partial refunds, tip prompts, language selection, auto-receipt printing, end-of-day Z-reports, X-reports, and live analytics via a merchant portal.
Omnichannel Acquiring: Operates online checkout gateways (integrating with Shopify, WooCommerce, and Magento) under unified daily settlement reporting.
24/7 Operational Support: Offers round-the-clock telephone and email assistance to ensure multi-shift hospitality or continuous retail businesses never face downtime.
SumUp: The Flexible Pay-As-You-Go Champion
SumUp is designed for sole traders, mobile vendors, freelancers, and small businesses needing an easy start with no long-term commitment.
No-Contract Pay-As-You-Go: No monthly maintenance fees; you only pay a flat 1.69%–1.75% fee when you process a sale.
Versatile Hardware Lineup: Options range from the pocket-sized SumUp Air (connects via Bluetooth) to the standalone touchscreen SumUp Solo (with integrated SIM/Wi-Fi) and complete POS setups (SumUp POS Lite and Goodtill by SumUp).
Tap to Pay on Smartphone: Allows merchants to transform an iPhone or Android phone into a contactless card terminal without buying extra hardware.
Free Business Account & Card: Provides a built-in SumUp Business Account with a Mastercard debit card, unlocking same-day or next-day payout access.
Online & Remote Tools: Includes a built-in mini online store builder, payment links via SMS/email, virtual terminal invoicing, and appointment booking via SumUp Bookings.
Advanced Hospitality Add-ons: Uses its Goodtill acquisition to supply modular hospitality software for table layouts, kitchen display systems (KDS), and inventory.
Zettle by PayPal: The Retail & Ecosystem Specialist
Acquired by PayPal, Zettle combines build quality with seamless sync across the broader PayPal financial ecosystem.
Integrated PayPal Processing: Offers a standard flat fee (1.69%–1.75%) for card payments, while natively supporting PayPal and Venmo QR codes, Buy Now Pay Later (BNPL) checkout, and digital mobile wallets.
Built-in Inventory & Catalog Management: Provides variant management, matrix inventory tracking, barcode scanning, and stock alerts directly within the free Zettle app.
Robust Hardware Options: Features the tactile Zettle Reader 2 (built for heavy daily counter use) and the all-in-one Zettle Terminal with built-in printing and cellular connectivity.
PayPal Business Wallet Liquidity: Transfer processed funds straight into a PayPal Business account within hours to pay suppliers or make online business purchases immediately.
Deep Accounting & E-Commerce Sync: Features pre-built integrations with Xero, QuickBooks, Shopify, WooCommerce, and Adobe Commerce (Magento).
Multi-Staff & Shift Tracking: Free staff accounts with custom permission levels, individual sales tracking, and tipping allocation tools.
3. Which One Should You Choose?
Choose Flatpay if: You run a physical storefront, restaurant, salon, or high-volume business turning over more than €5,000–€10,000 per month. Flatpay’s lower processing rates (0.99%–1.49%) save thousands in fees annually compared to standard 1.75% rates, and their included 24/7 support and on-site setup keep physical operations running smoothly.
Choose SumUp if: You are a sole trader, mobile service provider, or pop-up merchant processing variable or low monthly volume. You get low upfront hardware costs (£29/€29), no monthly commitments, and fast payouts with their free business card.
Choose Zettle if: You rely on PayPal for business operations, need strong inventory tracking right out of the box, sell across online and offline channels simultaneously, or require automatic syncing with accounting software like Xero or QuickBooks.