At the terminal the three cards look the same; in the statement they are worlds apart: in the same price lists girocard sits at 0.16 to 0.26 per cent, the international debit card at 0.89 to 1.25 per cent. Where the difference comes from, what it costs on a real card mix, and who decides at the terminal which brand runs.
“The most expensive card payment of the day is often the one where the customer did nothing differently — they simply had a different card in their hand.”
Cash counts as the free means of payment because no fee statement comes with it. The Bundesbank has measured it: per payment, cash really is the cheapest, but relative to turnover it costs almost three times as much as girocard. With the cost components on both sides, the bank charges for paying cash in, and the sum per ticket size.
“Cash has no fee statement — it has a timesheet nobody writes.”
Amex has a reputation for being expensive — but the sum is almost always set up wrongly. What matters is not the percentage, but the route you accept through, how large your Amex share actually is, and what a turned-away guest costs. With figures per ticket size and the thresholds at which the advertised entry price ends.
“The Amex question is rarely decided by the fee and almost always by the guest who otherwise pays somewhere else.”
The EU has capped the interchange fee — but expressly not for corporate cards, cards from outside the EEA and three-party systems. What that costs, why it hits your largest bills of all, and which pricing model is right for which card mix.
“The EU cap ends precisely where your largest bills begin — with the business customer’s corporate card.”
Buying is cheaper than renting — that sentence only holds if you calculate over a long enough period. Worked through with the published terms of CCV, SumUp, PayPal and myPOS, including the question that matters more than the device price: what does buying change about the contract term? Usually nothing.
“The purchase price of a terminal is rarely the problem — the commitment attached to it almost always is.”
The merchant discount rate is only the beginning. Who gets which share of the fee, what girocard costs compared with a credit card, why the same terms produce a completely different fee burden from sector to sector — and why on small tickets the advertised percentage barely matters.
“A per-transaction fee of nine cents turns a five-euro ticket into a fee of 1.8 per cent, before the advertised merchant discount rate has even been counted.”
A pure card terminal needs no certified technical security device — a SmartPOS with a till app does. Exactly where the line runs, what chain of duties hangs on it (TSE, receipt, notification to the tax office), what the TSE costs per ticket, and what the bill of 7 August 2026 envisages for a mandatory till from 2028.
“The TSE question is not decided by the device but by its function: as soon as the terminal enters orders, it is a till — and from then on the whole chain of security device, receipt and notification applies.”
Today there is no obligation in Germany to accept cards — there is a key-points paper from the Federal Ministry of Finance of 11 September 2026, a cabinet decision planned for this year and entry into force in 2027. What of that is law in force, what is merely intention, and why the ban on minimum amounts is the most expensive line of the paper for small tickets.
“An obligation to accept cards only becomes a burden when a business goes into the contract without its own figures — the obligation costs little, the wrong contract costs again every year.”
50 euros per payment, then a PIN after five transactions or 150 euros in total at the latest. Both limits are set out in Article 11 of Delegated Regulation (EU) 2018/389, not in your terminal contract. What the merchant can influence, what the card decides and how often the PIN appears at a given ticket size.
“A PIN prompt on a 12-euro payment is not a terminal fault and not a trick played by the payment network operator — it comes from the card.”
48 or 60 months initial term, renewal for twelve months at a time, three months' notice — miss the cut-off date and you are stuck for another year. The documented clauses of the large providers, a calculation of what a missed date costs depending on ticket size, and the five traps beyond the deadline.
“The most expensive clause in a terminal contract is not the merchant discount rate, it is the sentence about automatic renewal.”
A card tip runs in the same transaction as the bill, lands first in the business's account and incurs a merchant discount rate there. How the function works technically, why girocard has no subsequent adjustment, and what applies for tax: section 3 no. 51 EStG, section 10.1 UStAE, section 146 AO.
“The tip belongs to the staff, but the fee on it is paid by the landlord — on every cent that runs through the same terminal.”
Three routes lead from the till system to the card terminal, and the merchant pays twice for the wrong one: once at setup, then every day re-keying amounts. What technically separates ZVT, O.P.I. and cloud integration, why TA 7.2 is not the same thing, and from what number of tickets the integration pays for itself.
“Till integration pays off not through ticket size but through ticket count — which is why the bakery needs it more urgently than the trades business.”
Payment network operator, acquirer, card scheme, issuing bank: who does what in a card payment, why girocard has no acquirer, and what “commercial payment network operator” really means.
“In a card payment the merchant does not have one contractual partner but four, and the lack of transparency in card fees arises precisely in the joints between them.”
Countertop, mobile, SmartPOS, PIN pad, unattended: the hardware is the same at almost every payment network operator. What distinguishes the form factors, what to watch for in certification and platform, and when Tap to Pay on a smartphone is enough.
“The terminal is never the differentiator, everyone fits the same four manufacturers; what decides it are the terms, the service and the connection to the till system.”
Low value up to 30 euros, transaction risk analysis up to 500 euros, recurring payments, trusted beneficiaries: which exemptions from the two-factor requirement the law allows, how much of that providers actually implement, and why every exemption used shifts liability to the merchant.
“Every exemption from strong customer authentication is a trade: fewer abandoned baskets for more liability, and anyone who does not understand that trade is surprised by the chargebacks later.”
With cards the customer has 120 days and has to give a reason, and the merchant can defend itself with evidence. With SEPA direct debit the customer has eight weeks and does not have to give any reason at all. Deadlines, fees and defence compared.
“Direct debit is the cheapest payment method in online retail and the only one where the customer can claw the money back for eight weeks without giving a reason; anyone who only looks at the price does not see the risk.”
How a shop connects payments technically decides onboarding time, conversion and security effort. An overview of the integration types, the payment method mix in the DACH region and the payment link as a sales channel without a shop.
“The hosted payment page is not the convenient solution, it is the smart one: it takes the bulk of the PCI obligations off the merchant, and that is the most expensive item nobody sees in the quote.”