How Crypto Meets Fiat: New Infrastructure for the Hybrid Economy

A few years ago, crypto and traditional finance felt like two separate systems. Banks avoided blockchain exposure, crypto wallets were isolated from fiat rails, and users had to rely on external exchanges just to move money between the two worlds.

Today, the boundary is far less visible. Payment platforms and neobanks allow users to hold fiat and crypto side by side in the same interface. Services like Revolut and PayPal let people buy and sell Bitcoin alongside euros and dollars, without switching products or providers. For users, crypto increasingly feels like just another asset type rather than a separate ecosystem.

This user experience is possible because of new integration tools. Fiat onramps and offramps, custody services, and exchange APIs now work together to manage settlements, compliance, and liquidity. Rather than competing, crypto and traditional finance are being connected through shared infrastructure.

People often call this merging a hybrid economy. Tools like Fireblocks, Moralis, Kraken API, and Coinbase Prime API are the main technologies behind these systems. They make it possible to keep assets safe, manage transactions, and get real-time access to liquidity for both regular money and crypto.

Why Crypto and Fiat Are Finally Converging

Crypto and traditional finance used to feel like two separate worlds. One was fast, borderless, and flexible. The other was regulated, stable, and familiar. Now, those worlds are getting closer, not because of hype, but because people and businesses want tools that combine the strengths of both.

More users now expect wallets that support both crypto on-ramps and off-ramps. They want to hold USDT next to EUR, or top up a card with fiat while keeping part of their savings in crypto. Apps like Revolut and PayPal have already shown that this hybrid model works.

Revolut lets users convert between fiat and crypto inside a single account, while PayPal allows buying, holding, and sending crypto using the same wallet people already use for traditional payments. Most of the on-ramp and off-ramp logic stays behind the scenes, but the convenience it creates is very visible to users.

That level of convenience is becoming the new standard.

Demand is also visible in the numbers. According to Chainalysis, stablecoins already account for more than 52% of all crypto transaction volume under $1M in Central, Northern, and Western Europe. This shift shows that people are using them less for trading and more as everyday financial tools, basically as digital dollars that move smoothly inside regular fintech systems.

Research from the European Central Bank also points to the same trend. A single global factor explains nearly 40% of all variation in bitcoin–fiat trading volumes, which means crypto and traditional financial markets are becoming closely connected. When activity in one moves, the other tends to move with it.

As these two systems continue to overlap, users naturally expect products that support both worlds. Multi-currency wallets, crypto-friendly banking apps, and instant bridges between fiat and digital assets are becoming the new baseline instead of advanced features. Banks and payment providers are responding. What used to be a closed ecosystem is now opening up, with financial institutions exposing APIs or offering regulated ways to interact with digital assets. This makes it easier for wallets to support both sides of the economy without breaking regulatory compliance requirements, including frameworks such as MiCA (Markets in Crypto-Assets) in the European Union.

The last part of the puzzle is infrastructure. Tools like Fireblocks, Moralis, Kraken API, and Coinbase Prime API provide fintech teams with everything they need, including secure custody, transaction signing, on-chain data, liquidity access, and easy fiat on- and off-ramps. Instead of building everything themselves, teams can use these services to launch hybrid products much faster.

All of this leads to one clear conclusion: the convergence is no longer theoretical. Users want it, businesses benefit from it, and the infrastructure is finally ready to support it.

The Infrastructure Powering the Hybrid Economy

When people talk about “crypto meets fiat,” they often imagine just the visible part: apps where you can hold both dollars and USDT, or banking platforms that let you buy Bitcoin with a card. But the real transformation is happening underneath, in the infrastructure that makes all these features possible.

Most fintech products don’t build everything from scratch. Instead, they rely on specialized services that take care of the hardest parts: custody, security, transaction signing, on-chain data, liquidity, and compliance. These platforms act like the plumbing of the hybrid economy, connecting crypto and fiat behind the scenes so the end user gets a smooth, unified experience.

Here are some of the main tools shaping this new era:

Fireblocks

Fireblocks is one of the biggest names in digital asset custody and transaction management. It gives fintech companies secure ways to store assets, automate transfers, and manage wallets across multiple blockchains. For businesses, this solves two huge problems: security and compliance. Instead of building a secure custody system internally, teams can rely on Fireblocks’ infrastructure to handle crypto transactions safely.

Fireblocks uses Multi-Party Computation (MPC). Private keys are split across multiple parts and never exist as a single key, making custody more secure.

Moralis

Moralis focuses on the data side. It provides easy access to blockchain information like wallet balances, token lists, transaction history, and metadata across multiple chains. For hybrid apps, this means you can display on-chain balances right next to fiat ones, track user activity, and sync blockchain events with your backend without writing complex node integrations manually.

Kraken API

Kraken’s API gives developers access to fiat on-ramps, off-ramps, institutional-grade liquidity, and trading pairs. This is essential for apps that want to let users buy crypto with fiat, swap assets instantly, or build automated investment features. Instead of managing liquidity internally, teams tap into Kraken’s deep order books.

Coinbase Prime API

Coinbase Prime offers regulated custody, institutional trading, and fiat rails. For apps that must meet strict compliance standards, this is one of the safest ways to support crypto–fiat interactions. It allows fintech startups to integrate deposits, withdrawals, conversions, and secure asset storage without needing a banking license.

What ties all these tools together is a simple idea: fintech teams no longer need to build the crypto side from zero. They plug into infrastructure providers that already solved the hard problems. This is exactly why hybrid apps are growing so quickly. The barrier to entry is lower than ever, while user expectations are higher than ever.

The result is a new generation of products that feel seamless. A user opens a wallet app and doesn’t think in terms of “crypto” or “fiat” anymore. They just see money, in different forms, all managed in one place.

What Hybrid Products Look Like in Practice

It’s one thing to talk about crypto–fiat convergence in theory, but the real story becomes clear when you look at actual products. Many of today’s most popular financial apps are quietly becoming hybrid platforms, even if they don’t market themselves that way.

The shift often begins with small features, like buying some Bitcoin in a banking app, sending USDT to a friend, or topping up a debit card with stablecoins. Once these features are available, users want more. They expect the same smooth experience whether moving euros, dollars, USDT, or Bitcoin.

Here are some of the most common patterns in hybrid products today:

Multi-currency wallets

These wallets let you store and move both fiat and digital assets in one place. A person might keep long-term savings in BTC, everyday spending money in EUR, and trading funds in USDT. The important thing is that switching between them feels natural.

Revolut is the best-known example. It lets users exchange fiat and crypto instantly, track prices, and even send digital assets to other users. PayPal works similarly, allowing users to buy and hold crypto inside a traditional payment app.

These products showed the market something important: people want fewer accounts, not more. They want one wallet that does everything.

Cards backed by crypto

Another fast-growing trend is debit cards connected to digital assets. Users can pay in fiat, but the card automatically converts from stablecoins or even Bitcoin behind the scenes. For them, it feels like a normal purchase, but the balance can be held entirely in digital currency.

This is popular with people who want to keep crypto long-term but still use it when needed, without having to sell it each time.

Crypto-backed borrowing

Borrowing against crypto without selling it is becoming a mainstream use case, especially for people who don’t want to lose long-term upside. Platforms let users deposit BTC or ETH as collateral and receive fiat or stablecoins instantly.

It’s the clearest example of hybrid finance: users interact with crypto on one side, but receive money they can use anywhere on the other.

We’ve already developed this feature for one crypto app. You can read the article and case study here.

Savings and yield products

Some apps now allow users to earn interest on stablecoins while having the option to withdraw funds to a traditional bank account. Others let people allocate part of their savings into crypto portfolios managed by automated strategies.

These products sit right between traditional banking and Web3. They offer higher flexibility than banks, but with a familiar interface and clear reward structures.

Business tools

Hybrid features are also moving into B2B products. Companies can pay contractors in USDT, store treasury funds in stablecoins for international operations, or cash out to fiat through integrated banking partners. Startups building in emerging markets especially rely on these tools because stablecoins offer more consistency than local currencies.

What all these examples have in common is that users no longer distinguish between crypto operations and “normal” banking actions. They just want one system where all forms of money work together smoothly.

For fintech teams, this means one clear thing: the future is in products that support both the stability of fiat and the flexibility of crypto, without making the user think too much about what happens in the background.

Challenges When Building Crypto-Fiat Products

Building a hybrid product sounds exciting, but it’s also one of the hardest categories in fintech. You’re not just dealing with two different technologies — you're dealing with two different worlds, each with its own rules, risks, and expectations. When they meet inside one platform, even simple features become more complex behind the scenes.

Here are the biggest challenges fintech teams face when designing crypto–fiat products.

1. Compliance that changes by region

Traditional finance is heavily regulated. Crypto is regulated unevenly. And hybrid products must satisfy both.

A feature that is fully legal in one country can be restricted or banned in another. This affects everything: onboarding, KYC levels, deposit methods, withdrawal rules, and even how stablecoins are displayed.

Teams need flexible flows so the interface can adjust to different jurisdictions, age requirements, AML rules, and tax obligations, all without confusing users.

2. Connecting fiat rails with blockchain rails

Fiat transactions rely on banking partners, payment processors, and card networks. Crypto transactions move through nodes, smart contracts, and custody providers.

Bridging these rails is technically challenging because they work at different speeds and have different failure points. Fiat payments can be delayed, while blockchain transfers are final. Combining them requires clear logic for: delays, partial failures, currency conversion, settlement differences, multi-network support.

A hybrid product should hide these differences from the user.

3. Handling delays and volatility

Crypto is fast, but not always predictable. Network fees can skyrocket, block confirmations can slow down, and asset prices can change dramatically in minutes.

Bridging these rails is technically challenging because they work at different speeds and have different failure points. Fiat payments can be delayed, while blockchain transfers are final. Combining them requires clear logic for: delays, partial failures, currency conversion, settlement differences, multi-network support.

The challenge is to make the user experience feel consistent. If a wallet delays fiat deposits but instantly shows USDT transfers, it should set expectations and communicate clearly, or users may think something is wrong.

4. Secure custody and permissions

Hybrid apps need to protect both fiat and crypto balances. This usually requires:

• MPC wallets or custody providers like Fireblocks
• strict role-based access for operators
• multi-step approvals for withdrawals
• monitoring for suspicious patterns

Security becomes more complex because you have to combine banking-level protection with Web3-specific security controls.

5. Transparent UX for different money types

Many users still don’t fully understand how crypto works. They may not know why transfers get stuck, why confirmations matter, or why stablecoins behave differently than fiat.

A good hybrid product must make the experience feel intuitive:

• one balance
• clear labels
• predictable flows
• no jargon unless necessary

6. Reliable on- and off-ramps

One of the hardest parts of hybrid products is moving money between systems. On-ramps allow converting fiat into crypto. Off-ramps convert crypto back to fiat.

Both depend on partners such as exchanges, banks, and card processors, and those partners often change their rules, APIs, or limits. Keeping integrations stable requires constant monitoring and backup options.

Real Products Already Using Crypto–Fiat Infrastructure

The shift toward hybrid finance isn’t theoretical. You can already see it in popular apps that millions of people use every day. These platforms quietly rely on infrastructure providers like Fireblocks, Moralis, Coinbase Prime API, or Kraken to handle custody, liquidity, and crypto rails.

Here are some well-known examples.

Revolut

Revolut uses a combination of internal rails and third-party providers to support crypto trading, fiat accounts, and instant swaps between the two.

Users can hold EUR, USD, GBP, alongside BTC, ETH, and stablecoins in the same wallet. Behind the scenes, custody and liquidity are powered by regulated partners (Coinbase Prime and Fireblocks have been publicly mentioned as part of that stack).

PayPal + Venmo

PayPal introduced crypto buy/hold/send in 2020 and later expanded it with on-chain transfers using a built-in custodial wallet.

They rely on Paxos as the issuer of PYUSD, operating a regulated infrastructure stack for stablecoins and crypto–fiat conversion flows. Their stablecoin, PYUSD, is integrated into PayPal and Venmo and can move between crypto and fiat balances seamlessly.

Nexo & Binance Pay

These platforms let users store fiat and crypto, pay merchants, and move funds between both with minimal friction. Behind the scenes, they rely on a mix of bank APIs, card processors, blockchain nodes, and custody solutions, including Fireblocks or proprietary MPC-based systems.

Crypto.com

Crypto.com combines fiat cards and crypto wallets within a single ecosystem. It tracks balances, card spending, and on-chain transfers in real time, while working with multiple liquidity providers, custodians, and payment processors across different regions.

Trustyfy

Trustyfy provides bankless crypto-friendly accounts and cards that let individuals and companies hold and convert between fiat and crypto under one roof. It combines traditional banking elements (fiat accounts and VISA cards issued by regulated partners) with multi-chain crypto wallets, enabling seamless movement of funds across both worlds.

Why Stablecoins Became the Default Bridge

If you look at today’s crypto–fiat products, almost all of them rely on stablecoins. They quietly became the easiest way to connect the two worlds. And there are a few clear reasons for that.

Stablecoins behave like digital dollars.

Users can move USDT or USDC instantly, without waiting for bank transfers or dealing with cut-off times. For someone sending money abroad, or for an app processing global payments, this speed matters more than anything.

They are predictable.

The value stays close to one US dollar, so people and businesses can plan with it. Whether you’re building a savings feature or topping up a virtual card, you don’t want volatility to break the user experience.

They work well with existing fintech flows.

Stablecoins settle fast, integrate easily with blockchain rails, and don’t require building a full banking infrastructure from scratch. This is why many wallets now treat USDT and USDC the same way they treat fiat balances. Users barely notice the difference.

And finally, stablecoins fit naturally into multi-currency products. People can keep EUR, USD, and USDT side by side, move between them in seconds, and use whatever works best in the moment. For startups, stablecoins cut through the complexity of cross-border finance. For users, they feel like a simpler, faster version of digital cash.

All of this makes stablecoins the default bridge between crypto and traditional money, not because they’re trendy, but because they solve real-world problems better than most alternatives.

Where This Hybrid Model Appears Next

The crypto–fiat blend we’re seeing now is only the beginning. As infrastructure gets better and banks open their APIs, more products will start mixing digital assets with traditional money in ways that feel natural to everyday users.

Salary and payroll.

We’re already seeing companies experiment with paying employees partly in stablecoins and partly in fiat. It’s fast, global, and avoids expensive international transfers. For remote teams, this model removes a lot of friction.

Merchant and checkout payments.

E-commerce platforms are beginning to accept crypto behind the scenes, even when customers pay in fiat. A user pays with a card, the merchant receives USDC instantly, and settlement becomes much simpler for global shops.

Travel and cross-border spending.

Travel cards that automatically convert between crypto and fiat at the moment of payment are starting to gain traction. For users, this feels like having one wallet that works everywhere, no matter the currency.

Savings and yield products.

Fintech apps will start offering mixed savings accounts where fiat earns interest through banks, and stablecoins earn additional yield through regulated protocols. This kind of hybrid savings experience is already being tested.

Marketplaces and gig-economy platforms.

Creators, freelancers, and sellers increasingly want payouts that settle instantly. Hybrid rails make it possible to send earnings in USDC while still showing balances in local fiat.

Super-wallets.

Many crypto apps are transitioning into all-in-one financial hubs. One interface, multiple balances, crypto on one side, fiat on the other. Transfers, cards, staking, and payments are running through a mix of banking rails and blockchain rails hidden behind the UI.

All of these examples point to the same idea: the next wave of fintech won’t be crypto-only or fiat-only. It will be a combination of both, designed around convenience rather than ideology. Apps that adopt this hybrid approach early will feel modern and flexible. Apps that don’t will eventually feel outdated.

Final Words

The line between crypto and traditional finance is disappearing much faster than most people expected. What used to look like two separate ecosystems is now blending into one. Users can move money across borders in seconds, hold dollars and stablecoins in the same wallet, and switch between crypto and fiat without thinking about the rails behind the screen.

The numbers match this reality. A study by the European Central Bank found that global drivers account for about 40% of variation in Bitcoin–fiat cross-border flows, underscoring how intertwined crypto and traditional money are becoming.

The trend is clear. Users want hybrid products. Banks and fintech platforms are opening the door. And the infrastructure is finally mature enough to make it all work safely and at scale.

For product teams, the question is no longer “Should we support both crypto and fiat?” It’s “How soon can we do it?”

And the companies that adapt early will have a real competitive advantage: faster onboarding, wider payment options, and global reach without spending years building rails from scratch.

At Stubbs, we work closely with teams building at this intersection. We’ve helped fintech products add crypto on-ramps and stablecoin flows, and supported crypto-native platforms in integrating fiat rails and compliant custody. If you’re exploring a hybrid model, we’re always open to sharing our experience and discussing practical next steps, whether that’s architecture, infrastructure choices, or product design.

The next generation of fintech will not be crypto-only or fiat-only. It will be built where both worlds meet, with products designed around convenience, trust, and flexibility rather than ideology.