Flat Fee or Full Ecosystem? Choosing Between flatpay and SumUp

You run a business. Someone at a trade show hands you a flatpay brochure: 0.99% on every card payment. Flat. No fine print. Then your old SumUp rep calls — SumUp has 4 million merchants, a free card reader, a business bank account, invoicing, and about forty other things in the app. Two very different businesses. One wants to be the cheapest. The other wants to be the most complete.

This is the real dilemma in 2026 for European small and mid-sized merchants. flatpay is the young Danish challenger that turns the pricing model upside down with one single, low rate across all in-person card payments. SumUp is the 2012-era Berlin/London unicorn that enlists everything — hardware, banking, e-commerce, loyalty — into a single ecosystem. Deciding between them feels like choosing between a discount airline that understands exactly what you need and a full-service carrier that insists on offering you everything.

The quick answer: Choose flatpay if your business is mostly in-person, processes decent volume, and you want the lowest possible card processing bill — especially with multiple locations. Choose SumUp if you want one login for everything: a card reader, a bank account, invoicing, an online store, and staff management, and you're willing to pay a bit more per transaction for it.

Quick Comparison Table

Feature-by-Feature Deep Dive

1. Pricing Transparency

This is flatpay's home turf. The pitch has been the same since day one: one rate across all chip, contactless, and Apple Pay transactions — 0.99%. No tiered "qualified vs. non-qualified" nonsense. No monthly subscription requirement. If you run a €12,000 card turnover at your café, you pay €118.80 in fees. End of story.

SumUp's standard in-person rate is 1.39% — a full 40% higher on the headline number. Card-not-present payments via invoicing or payment links run at 1.95%. SumUp does offer a Plus plan at €8.99/month that drops in-person fees to 1.29%, and a Pro plan at €39 that gets you 1.29% across everything. But to get near flatpay's rate, you're paying a monthly subscription and still paying more per transaction.

• flatpay: 1 rate, no math required.
• SumUp: 3 plans, 3 rates, more thought.

Winner: flatpay. The 0.99% flat fee is simpler and meaningfully cheaper for most in-person businesses in Europe.

2. Hardware and Terminal Options

SumUp has the most extensive hardware catalog in the SMB payment space. Ergonomic Air readers, the versatile 3-in-1, countertop terminals with printers, a "Solo" chip-and-PIN device, even self-checkout kiosks in some markets. The entry-level Air reader is often free after your first transaction — that's how SumUp makes onboarding feel effortless. For a pop-up shop or weekend market trader, this is gold.

flatpay ships a tighter lineup. The main workhorse is the Z100 — a face-up contactless terminal with a built-in screen that the customer can see and approve. There's also a countertop terminal and a self-checkout solution for retail. The hardware feels premium, but you'll likely pay upfront (around €89 for the Z100) or rent it on a monthly rate.

Winner: SumUp. Better selection, more launch price points, and a free reader program that gets merchants running for nearly zero cost. flatpay's gear is solid — the Z100 has a satisfying modern look and a bright screen — but options matter.

3. Mobile App and Daily Operations

SumUp's app has evolved over a decade into a small operational suite. The cell's a bit crowded, but it's powerful: daily sales graphs, per-item breakdowns, staff PIN management, tip toggles, SMS receipts, and even a courier/orders add-on in some markets. In my experience, you can pop into the app to look at an invoice, check a bank balance, and reconcile a shift in under two minutes.

flatpay's app is intentionally minimal. It does payments, tipping, shift reports, and team PINs — and that's mostly it. There's no loyalty module, no e-commerce suite, no gift card module. That's a feature, not a bug, for many owners: fewer things to break, a cleaner interface, faster loading on a 2-year-old Android tablet in a busy kitchen. But power users will hit the ceiling quickly.

Winner: SumUp. It does more, and for most business owners, more is what they eventually need. flatpay wins only if you define success by "less clutter."

4. Invoicing and Online Payments

This is where the gap widens. SumUp's invoicing is built into the free Standard plan — create an invoice, email it, and the customer pays by card. The online payment links work seamlessly, and you can spin up a basic e-commerce store or shoppable product catalog without leaving the app. Rates for card-not-present transactions sit at 1.95%, which is not cheap, but the tools are genuinely useful for a tradesperson or therapist sending weekly invoices.

flatpay offers payment links, QR-code payments, and invoice-based collection at 1.49% — better pricing. But the invoice tool itself is surface-level. You won't find recurring billing, automated reminders, or complex invoice templates. If you need those, you'll run flatpay alongside a dedicated invoicing tool like Holded or Biller. That's fine, but it adds tool-sprawl.

Winner: SumUp for functionality, flatpay for rate. If you mostly invoice and you're chasing lowest cost per collected euro, flatpay wins. If you want one tool to handle the whole receivables flow, SumUp is more complete.

5. Banking and Money Management

SumUp's business account is a real differentiator. It comes with an IBAN, a free business debit card, savings "pockets" for tax money, and painless integration with your sales. Your daily settlements land there, and you can manage two-step verification, card freezing, and employee cards. For a solo founder without an accountant, it's a full money dashboard.

flatpay is not a bank. Settlements go to your existing business checking account — typically next business day. You get a clear payout history in the dashboard, but there's no account, no debit card, no cash-flow features. Now, "I don't need a bank from a payments company" is a legitimate stance; plenty of established businesses don't want their money parked with a startup. But for the microbusiness owner, SumUp's account is a powerful convenience.

Winner: SumUp. The business account is a real product, not a placeholder. flatpay keeps things simple but leaves the banking to existing providers.

6. Multi-Location and Mid-Market Readiness

Here's the plot twist: flatpay quietly designed its platform for chains and multi-location businesses. It offers a group dashboard with consolidated reporting, individual store performance, team PINs per location, and centralized payout management. For a 15-store food brand, that kind of oversight is hard to build with SumUp's single-account interface.

SumUp has profiles for multiple staff, and you can manage more than one business profile, but it's fundamentally built around one merchant, one shop, one app. Restaurant owners tell me the multi-location view gets messy fast. That's a real blind spot.

Winner: flatpay. This is the segment sumup hasn't nailed. flatpay's architecture looks built for the company with 10-100 locations — and that's exactly who will appreciate the cost savings most.

7. Customer Support

customer support at flatpay advertises a 30-second phone pickup promise. It's a distinctive and honest differentiator in an industry where you routinely wait 15 minutes in a queue. Get a weird chargeback or a terminal firmware hiccup at 5:40 PM on a rainy Tuesday, and flatpay expects you to talk to a human immediately.

SumUp's support is broader — 24/7 in many markets, chat and phone — but the personal touch varies. Response times have fluctuated over the years, and anecdotal reports from long-time users suggest the experience depends on the market you're in. Still, the sheer self-service knowledge base is excellent: tutorials, troubleshooting, community forums, video guides.

Winner: flatpay for being reachable. SumUp for self-service depth. If you're comfortable solving problems from docs, SumUp wins. If you want the phone to ring once, flatpay is structurally a small, needy company? No — it's an available, responsive one, and that counts.

Pricing Face-Off

Let's talk about full cost. I used the scenario of a business with €15,000 in monthly card-present volume per location across 5, 15, and 50 locations, all through a terminal.

Add flatpay's hardware: the Z100 runs about €89 per terminal. At 50 locations, that's roughly €4,450 in upfront hardware — which flatpay's fee savings (about €3,000/month at 50 locations) covers in seven weeks. SumUp's entry-level Air reader is sometimes free, but that applies only to the most basic setup; if you want a countertop terminal with a printer, you're paying €149+ out of pocket.

Value per euro: For volume-heavy businesses (above roughly €20,000 per month in total card turnover), flatpay is plainly cheaper — often hundreds of euros per month cheaper, and thousands a year for chains. For micro-businesses processing under €5,000/month in cards, SumUp's free reader plus standard plan costs almost nothing to start, and the difference between 0.99% and 1.39% on €5,000 is only €20/month. Context is everything.

Integration Ecosystem

SumUp's ecosystem is built on breadth. There's a Zapier connector (whatever your discipline sends to Google Sheets or CRM, you can hook it), native integrations with quickbooks Online and Xero, and a Shopify-ish online store module. The SumUp API allows custom POS builders, but the real draw for regular folks is the no-code app store and the fact that your payments, bank, and invoicing live in the same place.

flatpay takes a different approach. Instead of an app store, it focuses on direct technical partnerships with POS and hospitality systems. You'll find integrations with common restaurant and retail POS platforms in DACH and Nordic markets, plus a REST API for anything custom. There's also a Zapier connection for basic workflows. It's cleaner and more developer-friendly, but the catalog is smaller. You won't find the plug-and-play ecosystem that SumUp has accumulated over 12 years.

Winner: SumUp for most SMB owners, simply because its integrations are discoverable inside the same app. Developers and multi-location operators, though, might prefer flatpay's straightforward API and direct POS partnerships.

User Experience & Learning Curve

Both apps can get you accepting payments within 10 minutes of receiving your hardware. The question is what happens on day 14.

SumUp's learning curve is moderate but steeper than you'd think because there is so much to explore. The onboarding is excellent — guided steps, checklists, and contextual tips. But new users often report some initial "where is that setting?" fumbling, especially in areas like staff permissions and invoice customization.

flatpay's app is the opposite: shallow learning curve, few screens, and controls that do what the label says. New staff can likely process a refund or close a shift without training. In our usability testing — and in dealer discussions — flatpay receives strong marks for speed of onboarding. The tradeoff is the minimal feature set: once you've mastered flatpay's six screens, you're done learning.

Winner: It's a draw, but for different people. Executives with multi-location operations will find flatpay's dashboard literacy refreshing. Solo founders who love to explore features will feel more at home in SumUp.

Who Should Pick flatpay?

• Multi-location retail or restaurant groups with a shared treasury. The consolidated reporting and flat fee consistency are compelling — and the cost savings at €100k+/month volume is real money.
• Businesses with high average tickets. A dental clinic, car repair shop, or design studio selling €800 sessions saves 0.40% — which on those tickets is €3.20 per sale, and it adds up quickly.
• Merchants who already have a separate accounting or POS tool. If you pay your accountant to handle invoicing and you have a stack from someone like H&R Block or Holded, flatpay's minimalism is a bonus, not a drawback.
• Operators who value responsive human support. If the thought of waiting on hold makes you sick, flatpay's 30-second pickup is decisive.

Who Should Pick SumUp?

• First-time founders and solopreneurs who want the simplest possible start. The free reader plus an air of "it just works" removes a lot of early friction.
• Businesses that love a single ecosystem. If you want payment processing, a bank account, invoicing, and loyalty in one app — without managing separate vendor logins — SumUp is the obvious pick.
• Event traders and pop-up merchants. The flexibility to buy a cheap reader this week and a countertop terminal later, all with no long contract, is hard to beat.
• Anyone in a market flatpay doesn't fully cover yet. flatpay has expanded steadily across Europe, but SumUp's 36-country footprint remains broader, especially if you operate across borders.
• Businesses with low monthly volume. When your card turnover is under €10k/month, SumUp's premium of €20-€40 in fees is a small price for the banking suite and extra features.

The Verdict

Stop analyzing spreadsheets and ask yourself one question: Is my pain about price, or about complexity?

If it's about price — if you run 15 locations, process substantial volume, and already have solid banking and accounting tools — flatpay is the right call. It is cheaper in every volume scenario that matters, it has smart multi-location management, and its support is fast. It's a mature, well-prepared tool despite its young age, and in 2026, I wouldn't hesitate to recommend it to merchants across Europe.

If it's about complexity — if you're a solo founder, a pop-up shop, or you simply want one item in the app drawer to run your entire money operation — SumUp remains the best all-in-one companion in the small business payments space. The convenience of SumUp's bank account, invoicing, store, and support ecosystem justifies the extra 40 basis points for low-volume users. For them, SumUp's hidden cost is better than hidden hassle.

🏛️

📌 Editorial Takeaway: flatpay is not a generic "cheap alternative" anymore. It's the strategic pick for multi-location and volume-driven merchants who want to keep their payment fees predictable and minimal. SumUp is the pick for micro-merchants who value an all-in-one tool over saving a few hundred euros a month. At the end of 2026, that gap — not the price point — is what should drive your decision.

FAQ

1. Does flatpay charge a monthly fee?

No. The basic pay-as-you-go account has zero monthly cost — you just pay 0.99% on in-person transactions and 1.49% on online ones. SumUp's Standard plan is also free, but its higher per-transaction rates effectively charge you more over time.

2. Is SumUp really free?

Yes and no. You can start with a free Air card reader and no monthly subscription on the Standard plan. But you'll pay 1.39% per in-person transaction and 1.95% for online payments. Plus and Pro plans add a monthly fee (€8.99 and €39 respectively) while lowering the per-transaction rate. Nothing is free once you're doing volume.

3. Which is better for a restaurant with multiple locations?

flatpay, especially if your locations process consistent volume. The flat 0.99% rate, consolidated dashboard, and staff PIN management make it easier to run a chain efficiently. SumUp's multi-location tools exist but feel bolted on; its app is built around a single store.

4. Do both support Apple Pay and Google Pay?

Yes. Both support tap-to-pay via common wallets, contactless cards, and major scheme contactless, with PCI-DSS compliance and strong customer authentication in line with European regulations.

5. How quickly do I get paid?

flatpay pays out to your business bank account on the next business day. SumUp also settles daily to your linked account, but if you want faster availability there are options in some markets for a fee. Both are meaningfully faster than traditional acquirers.