The finance industry is in the midst of a major shift powered by application programming interface, or API. In the past, banks built products as closed systems. Today, the rise of API-first fintech companies is flipping that model, with interoperability and openness at the center of financial services.
This transformation is closely tied to open banking, a movement that gives consumers greater control over their financial data and allows new providers to build services directly on top of traditional banking infrastructure. Together, API-first design and open banking are transforming how people move money, manage accounts, and even think about what a financial institution should be.
What ‘API-First’ Means in Fintech
In the fintech world, API-first is the idea of building financial products with the assumption that every feature will be shared or extended through an API. Instead of tacking on integrations later, companies design those connections from the ground up, making them part of the product’s DNA.
This shift has big implications. A startup no longer has to spend months wrestling with one-off integrations every time it wants to connect to a bank or payment provider. With consistent, well-documented APIs, partners can plug in quickly, developers can build on top of the same foundation, and new services can go to market in weeks rather than years.
Take account data as an example. The same bank API can power a budgeting app, help a lender verify income, or let a retailer offer embedded finance. Research shows that this approach not only boosts innovation, but also helps fintechs expand across markets and build ecosystems where third parties can add value with minimal friction.
The Regulatory Backbone Behind Open Banking
Open banking didn’t take off just because the technology was ready. Regulators have been the real force behind it, pushing banks to open up and making sure that consumers stay protected.
- United Kingdom—The UK has set the pace since open banking became mandatory in 2018. Around 15 million people use open banking in the UK each month, which is nearly one in three adults. Payments have led the way, with tools like variable recurring payments starting to replace older methods like direct debits.
- European Union—In the EU, policymakers are moving from PSD2, the rule that first pried open account data, to a new package made up of PSD3 and the Payment Services Regulation. The idea is to harmonize oversight across member states, improve security, and expand consumer rights.
- United States—The U.S. has moved more slowly, but 2024 marked a turning point. The Consumer Financial Protection Bureau finalized its Personal Financial Data Rights Rule, which requires banks to provide secure access to customer data, sets obligations for fintechs which use that data, and gives standards bodies a formal role in determining how APIs are implemented. The rule will be phased in, but legal challenges could alter the timeline.
How Open Banking Is Changing Finance
Open banking is already changing how people handle their money. Apps can connect directly to your bank account, which makes it easier to pay bills, track your spending, and manage subscriptions.
Smarter account aggregation and personal finance
Account aggregation is one of the most visible ways that open banking is changing finance. With a consumer’s permission, apps can pull together balances, transactions, and income data from multiple banks into a single dashboard. This makes it much easier to track spending, compare services, and switch accounts. Personal finance tools can now give genuinely useful insights instead of just showing static statements.
Payments Without the Middleman
Open banking is also changing how payments work. “Pay-by-bank” services enable customers to send money directly from their accounts to merchants, bypassing traditional card networks. That can make transactions faster, cheaper, and safer, since sensitive card details don’t need to be stored.
Variable Recurring Payments
Variable Recurring Payments (VRPs)are another innovation. Unlike standard direct debits, VRPs let consumers decide exactly how much can be taken, how often, and for what purpose. This gives people far more control over subscriptions and recurring bills, and it’s expected to expand into a wider range of services in the coming years.
Embedded Finance
Finally, open banking allows for embedded finance—when non-financial companies offer banking-like features inside their apps. Retailers, ride-hailing services, and even healthcare platforms can add payments, lending, or insurance features without building the underlying banking infrastructure. Standardized APIs make it straightforward, allowing more companies to offer financial services while keeping the user experience seamless.
Why API-First Matters for Incumbents and Startups
API-first is a strategy that is changing how financial companies operate.
For startups, it means that they can launch new features quickly, integrate with partners without months of custom work, and scale services without rebuilding from scratch.
For established banks, an API-first approach enables them to modernize legacy systems, offer data and payment services to third parties, and create new revenue streams through embedded finance or premium data offerings.
In both cases, the real benefit is speed and flexibility. Companies can innovate faster, respond to customer needs, and stay competitive in a rapidly changing market.