We live in an age of instant everything, except money. While streaming, shopping, and messaging operate in near real time, many banks still depend on overnight batch processing to move funds and reconcile internal ledgers. Event-driven architecture promises to change that by enabling true real-time payments. But what happens when transactions never sleep?

Instant everything, except money

We can order dinner or message across continents in seconds. Yet when you move money between banks, it can still take hours, or even until the next day. That lag isn’t magic or malice. It’s the legacy of systems built in a time when “end of day” actually meant something.

FinTech saw this gap and sprinted through it. PayPal made sending money feel instant, but only inside PayPal’s own walls. As soon as traditional banks are involved, for example to pay rent, you’re back to waiting for the funds to “clear.”

Twint is pushing those walls from the inside. It connects directly to users’ bank accounts, enabling peer-to-peer payments and even in-store transactions in seconds. For the user, it’s delightfully fast. But under the hood, Twint still fights with legacy infrastructure. It is an agile front end integrated with rigid core systems.

Twint’s success shows what’s possible when old systems are wrapped with modern integration layers. Similar solutions are being developed all around the world. 24/7 clearing of funds is an engineering challenge, and engineering challenges can be solved.

From Batch Jobs to Event Streams

That’s where event-driven architecture (EDA) comes in. In a traditional banking system, transactions are processed in batches. Data is collected, validated, and written to ledgers at fixed times. In an event-driven system, every payment or balance update is treated as an event. Each event is a small packet of data that triggers other systems to react immediately.

Imagine you send a payment.

1. The payment service publishes a „PaymentInitiated“ event to an event bus
2. The fraud service evaluates it in real time.
3. The ledger service updates the account balances.
4. A notification service pushes a confirmation to your phone.

No nightly batches. The entire system acts like a living organism, reacting instantly to changes in state.

Why Event-driven Architecture works

Event-driven Architecture offers several technical advantages.

• Low Coupling: Services communicate via events, not direct calls, reducing dependency.
• Scalability: High-throughput event brokers can handle millions of transactions.
• Resilience: A failing service doesn’t stall the entire system; events queue until the consumer recovers.
• Extensibility: New features can be added by simply subscribing to existing event streams.

It’s not just fast, it’s flexible too.

Real-Time Isn’t Free

Real-time brings real challenges. Eventual consistency becomes trickier when money is involved. A few milliseconds of mismatch can create money that appears to exist in two places at once. Traceability becomes harder as well. With hundreds of microservices handling thousands of events per second, following a single transaction for audit is like finding a specific drop in a waterfall.

Then there’s control and monitoring. Regulators demand a complete, immutable record of every transaction. Banks must ensure events are idempotent (processed once and only once), handle retries gracefully and monitor latency across many systems. Techniques such as event sourcing and saga patterns help keep order in the chaos, but they demand careful design from skilled professionals.

Lessons from Blockchain

Cryptocurrencies have already shown that 24/7 settlement is possible. A blockchain network never closes; every transaction is verified and added to a shared ledger in near real time, all the time.

The banking world can learn from this mindset. Availability through decentralization is a valuable lesson. The goal isn’t to replace core banking systems, but to adopt the principles that make continuous operation possible, and to do so within the guardrails of compliance and trust.

The Road Ahead

So where does that leave banks? In a hybrid world. Legacy cores won’t disappear overnight, but they can be wrapped with event-driven layers that handle real-time demands. Banks that embrace event-driven architecture will be ready to plug into the always-on economy. The world has already gone instant. Banking systems are just catching up.

Dieser Blog-Beitrag wurde mit Unterstützung von KI erstellt.