The Only Way to Scale Digital Payments Is Through Infrastructure

Mexico's central bank runs a payment system that settles money in seconds, free of charge, 24 hours a day. It has quietly become one of the busiest transfer networks in the region.

The system is called SPEI — the Interbank Electronic Payment System — and it has been operating since 2004.The Bank of Mexico's own 2024 report on financial market infrastructures puts the amount moved last year at MX$219 trillion (US$12.5 trillion). Settlement happens in seconds, at no cost to the person sending the money. By the end of 2024, four participants offering indirect connection were serving 93 smaller institutions — credit unions, savings cooperatives, electronic payment fund companies — none of which had to build their own bridge into the network to reach it. This is, by any technical measure, a well-built piece of plumbing.

What's easy to miss, going through Banxico's own numbers, is how much the composition of that plumbing's traffic has changed without anyone marking the occasion. In SPEI's early years, transfers of large sums — the kind moving between corporate treasuries, not between two people splitting a bill — made up close to 95% of everything on the system. By 2024 that share had fallen to 7.2%. Somewhere in the past two decades, a system built to let banks settle with each other quietly turned into a system dominated by small, ordinary transfers. That detail matters more than the headline volume, because it means the rails have already absorbed the kind of traffic a mass payment habit produces. The rails were never the bottleneck.

The habit is a different matter. Banxico's "2024 National Survey on Financial Inclusion" found that 23.7% of the population now pays using electronic transfers, up from 8.2% in 2021. That is real movement, nearly tripling in three years. It also leaves the large majority of the country outside the habit, in a place where free, instant transfers have existed for more than two decades.

CoDi, a way to pay by scanning a QR code, launched in 2019. DiMo, which lets someone send money using just a phone number instead of an 18-digit CLABE, followed in 2023. Both sit on top of SPEI. Both cost nothing to use. Neither has become second nature in the way tapping a card or handing over cash has. Banxico has begun merging the two into a single flow — phone number and QR code together, inside the banking apps people already have opened — a move that reads less like an innovation and more like an admission that offering two separate tools mostly produced confusion.

This isn't a technology story. A system moving many multiples of a country's GDP in a single year does not have an engineering problem. What it has is a gap between what the rails allow and what an ordinary transaction actually rewards. Brazil is the usual comparison, and for good reason: Pix moved from launch to daily habit far faster than CoDi and DiMo have managed, largely because its rollout was coordinated across banks and retailers together with the central bank, rather than left as a feature any single institution could choose to push hard or let sit.

There is a pressure point worth naming that has already played out rather than one still ahead. Mexico's three host cities — Mexico City, Guadalajara, and Monterrey — carried their share of the 2026 World Cup through the group stage and the round of 32, with Estadio Azteca opening the tournament on June 11 to a sellout crowd of 80,824 for Mexico's win over South Africa. By the time Mexico's hosting window closed, the FIFA Fan Festival alone had drawn cumulative crowds of 527,100 in Mexico City, 244,710 in Monterrey, and 218,424 in Guadalajara, ahead of every fan zone in the United States or Canada. Mexican tourism authorities have put the country's total for the tournament period at more than 5 million international visitors, with tourism spending tied to the event estimated near US$1.4 billion. Most of that money moved through international cards, not local transfer rails — that part isn't in question. But a surge of that size forced merchants up and down the chain to modernize how they take payment at all, and the terminal upgrades that came with it have a way of leaving behind infrastructure that also makes it easier to accept a local instant transfer, provided merchants and financial institutions choose to build on those upgrades now that the tournament has moved on to the matches still being played in the United States.

I work inside a company that processes payments across several of these markets rather than just one, which offers a useful angle on the problem: it becomes clear fairly quickly which frictions are peculiar to a single country and which ones show up wherever a government tries to make a free, instant, official payment rail feel as ordinary as handing someone cash. In market after market, the sticking point is rarely the rail itself. It's the layer sitting on top of it — whether opening an account requires a trip to a branch, whether a phone-number transfer feels as fast as a tap, whether a small merchant treats an instant transfer as a real way to get paid rather than a secondary option next to the card terminal.

There is also a less visible argument here about cash. A payment method people trust enough to use daily chips away at reliance on cash, which still runs much of the country's day-to-day economy, particularly among smaller merchants and lower-income households. Every transfer that replaces a cash payment leaves a record, with consequences for tax formalization, credit access, and fraud detection that reach well beyond convenience. Banxico's effort to merge CoDi and DiMo, alongside the cryptographic and authentication upgrades it made to SPEI under cybersecurity rules that took effect in 2024, suggests the central bank has arrived at a similar conclusion.

The rails work. That part was settled years ago, quietly, the way most infrastructure gets settled. The open question is who manages to make the rails disappear into the background of daily life, the way nobody thinks about the wiring behind a light switch. Whoever solves that will not have built a faster system. They will have built one people simply use.