The Hotel Beneath the Casino
Every payment system works like Las Vegas: spotless on the surface, chaos underneath. This is how we built the tunnels, the hidden infrastructure that keeps commerce running in Latin America.
Understanding this hidden system is key to understanding how modern commerce actually works.
Every time you tap a card, an invisible conversation begins. It travels through banks, networks, and data centers across countries and currencies. Two seconds later, it comes back with a single verdict: approved or declined.
That small moment hides one of the most sophisticated systems humans have ever built. It is a choreography of trust that connects competitors, regulators, and technologies so different that they barely belong to the same century. At the heart of it all sits one elegant idea: the four-party model.
It is the system that lets you buy coffee in Tokyo with a card issued in Buenos Aires, pay for a Netflix subscription in San Francisco, or order something online from a merchant in Mexico.
Since we are talking about infrastructure, there is no better way to understand it than by looking at one of the most complex infrastructures in the world: Las Vegas.
A few weeks ago, at the Money 20/20 conference, a friend who spent a couple of years working in the Vegas hotel industry explained what really happens behind the scenes. Beneath every casino and lobby there is an underground city. Thousands of employees move through tunnels on small golf carts connecting kitchens, laundry rooms, supply areas, and maintenance stations. You never see a cleaning cart in the casino or a chef carrying food through the lobby. Everything runs below ground, 24 hours a day, without interruption.
That invisible network keeps the illusion alive. The lights stay on, the rooms stay spotless, and guests experience comfort without ever seeing the chaos underneath. Payments work the same way. A simple tap looks effortless, but underneath it, hundreds of systems talk to each other at the same time. Banks, acquirers, card networks, and processors exchange data in milliseconds to make something appear simple that is, in reality, incredibly complex.
If you could look under the surface of a payment, you would find a structure that looks almost alive. At one end is the cardholder, the person buying something. Then comes the merchant, the business selling it. The issuer is the cardholder’s bank, the one that approves or declines the transaction. The acquirer is the merchant’s bank, which processes the payment and ensures the funds arrive. At the center sits the network, such as Visa, Mastercard, or Amex, connecting everyone under a common set of rules.
Every payment begins with this sequence. The merchant sends the transaction to its acquirer, the acquirer forwards it through the network to the issuer, the issuer checks the details and returns an answer, and the response travels back the same way. It all happens in just a few milliseconds. Once approved, both banks record the transaction, which is called clearing, and soon after comes settlement, when the issuer sends the funds through the network to the acquirer, who deposits them into the merchant’s account.
In theory, this sounds simple. In practice, it is not. Between the merchant and the acquirer there is usually a payment aggregator, or PSP. The PSP connects to one or more acquiring banks and centralizes the flow of money. Since each card brand settles at a different time, the PSP receives all the funds, reconciles them, and allows the merchant to withdraw everything together through a single integration.
Sometimes, even when a merchant connects directly to an acquirer, the integration works as a passthrough. The merchant still communicates almost directly with each card network, dealing with their own timing, settlements, and reports. It is an unnecessary burden for any business that is not in the payments industry.
Using a PSP changes that. It becomes one integration and one unified dashboard from which merchants can track transactions, view settlements, and manage their funds.
PSPs also add more functionality on top of this. They give access to additional payment methods beyond cards, such as cash networks and bank transfers, and sometimes provide financial services like early payouts or working capital advances.
In the United States, Stripe plays this role. It is often described as a global operator, but in reality, it is a local acquirer. It processes transactions for businesses registered in the U.S., in U.S. dollars, through domestic acquiring. To use Stripe, you need a U.S. entity and a U.S. bank account. The illusion of global processing exists because the dollar is the default currency of international trade.
In Latin America, paying for international services just does not work as smoothly as one would expect. High fraud rates, currency restrictions, and local taxes make international processing unreliable. When a customer pays with a card issued in their home country to a foreign merchant (usually using a regular Stripe or Paypal link), the bank often flags it as suspicious. In Mexico, rejection rates for these cases can reach 50%.
Even when the payment succeeds, the customer gets charged an extra international fee by their local bank, a cost they never see during checkout. The price shown on the screen is not the price they actually pay. In Argentina, for example, during the period of dual exchange rates, Stripe’s checkout could show the equivalent of 100 USD in pesos, but by the time the card was charged, the customer paid 150 USD because of FX differences and hidden banking fees. That kind of friction destroys trust and discourages international purchases, even when prices are shown in local currency.
Now, it is true that Stripe operates in Brazil and Mexico, just as Mercado Pago and other PSPs operate regionally. But they do not let you operate in those countries unless you have a registered local entity there. To use Stripe Brazil, you need a company registered in Brazil. To use Mercado Pago in Mexico, you must have a Mexican tax ID.
The solution is cross-border aggregation, known as XB. Instead of sending payments to a foreign acquirer, Rebill act as the local payment facilitator, allowing consumers to pay in their own currency while the merchant receives funds abroad. It lets merchants process locally, stay compliant, and handle tax obligations transparently when applicable. They can operate safely without needing to register an entity in every country. And if one day they decide to open a local company, they can keep using the same infrastructure without changing their provider or integration.
This approach changes everything. Approval rates rise by up to 30%, locally issued cards beyond Visa, Mastercard, and Amex are accepted, and regional wallets such as Nequi, PIX, or QR Codes become available, along with cash payment networks. Consumers avoid hidden fees, and merchants do not need to create a company or open a bank account in every market.
To make this work, the payments processor must connect directly to the local acquirer in each market. Otherwise, it becomes another intermediary adding friction. That is the main difference between international PSPs and Rebill, which built those connections directly.
At Rebill, we became the PSP, connecting directly to local acquirers in each country. That gives us control of the full money flow, from authorization to settlement, and lets us optimize costs and speed at every step.
Building this required much more than software. For each country, we had to open legal entities, register with card networks, comply with central bank and tax authority regulations, set up AML procedures, and maintain PCI Level 1 certification, which is audited every year. We also built a financial hub to move funds that acts as our central vault - a single place to consolidate, convert, and move funds efficiently between markets.
After processing transactions locally in each market, we reconcile the funds received from acquirers, convert them into U.S. dollars, and send them to our financial hub.
Designing and implementing this system was one of the most complex challenges we have faced. In most countries, working with banks or FX providers still involves manual processes. Automating those flows of reconciliation, conversion, and settlement required designing our own infrastructure from the ground up. No one had done it before because it is extremely difficult, and most innovation in payments stops at the borders of the U.S. and Europe.
Even after settlement, the complexity continues. Not all payment methods release funds at the same speed.
• Credit cards settle between 3 and 18 days depending on the country and the issuer.
• Debit cards usually settle in T+1 day.
• Cash payments usually settle in T+1 day.
• Installment payments extend that even further.
Each card brand and issuer follows its own schedule and fee structure. Visa, Mastercard, Amex, and local networks all release funds differently. Costs also change by country and by MCC, the Merchant Category Code that identifies a business type.
This code matters because it defines how much processing costs for each vertical.
• A SaaS company might pay less than a travel agency.
• A subscription service might pay differently from a retailer.
• Even within the same brand, rates change by market.
On top of that, acquirers charge what is known as an interchange fee. It is small but variable, and it changes by country, card type, and MCC. By the time the funds reach the merchant’s account, the acquirer has already deducted:
• Processing fees
• Card network costs
• Applicable taxes
For us, this means every dollar must be traced precisely from the moment the customer pays until it lands in the merchant’s balance. That traceability is how we keep settlements transparent and accurate.
And then there is the part nobody likes to talk about: chargebacks. When a customer disputes a transaction, the card network requests the money back from the acquirer, which immediately debits the PSP. The problem is that by then, the PSP may have already released the funds to the merchant. To manage this, we maintain a rolling reserve, a portion of funds held in case of chargebacks. When necessary, we temporarily cover the gap with our own capital and later recover it from the merchant’s next settlement.
This level of precision and automation is what allows us to operate at scale without compromising performance or trust.
Today, Rebill not only supports merchants but also powers other aggregators and cross-border solutions. We provide them with white-label access to our infrastructure so they can scale across the 5 largest markets in Latin America: Argentina, Brazil, Chile, Colombia, and Mexico.
Other companies like dLocal or Ebanx built solid businesses, but their approach is different. They focus on large enterprises, building custom, people-driven solutions. Each client gets dedicated teams to handle things like FX rates, settlement timelines, and operational flows. It works well for companies processing over $5 M USD in monthly volume, where lower take rates still make financial sense.
The problem is that this model does not scale beyond the top tier. It leaves out the long tail, the thousands of software platforms and digital businesses that also want to operate regionally but cannot afford to set up local entities or manage dozens of providers.
That gap exists because the only way to solve it is by automating everything. You need automation in every layer, financial, operational, and regulatory, and that requires deep knowledge of how money actually moves. It means understanding FX, risk, and local taxes. But above all, it means having your own infrastructure, your own acquiring connections, and your own treasury. Without that, there is no way to make it work.
That is what we built. A system that runs on its own. A network where every process, from FX conversion to settlement, happens automatically and in real time.
We built it with a team of 12 people, automating every part of its core. The goal was simple: to make regional expansion in Latin America as easy as a single integration.
As Jony Ive once said, the better something is designed, the less you notice it. That is what we set out to build: something that works so well, you never have to think about it.