Inflexibility, not Legacy, is the Real Challenge in Cross-border Payments

For years, the payments industry has often framed modernisation around a familiar idea: that legacy infrastructure is the problem. Financial institutions have focused on replacing ageing systems, migrating to newer rails, and launching digital transformation programmes designed to modernise payment operations from the ground up.

Yet many of the systems commonly described as legacy continue to process cross-border transactions at enormous scale, with high levels of resilience and institutional trust.

In this article, we look at:

• Why legacy infrastructure is not the real issue in cross-border payments
• How ISO 20022 is exposing operational rigidity
• Why fragmentation is a permanent feature of global payments
• The growing importance of adaptive, multi-rail infrastructure
• Why flexibility, not replacement, will represent the future of payments

Why legacy infrastructure is not the real issue in cross-border payments

SWIFT moves trillions of dollars daily. Domestic real-time payment schemes such as Singapore’s PayNow, India’s UPI, and Brazil’s Pix continue to expand transaction volumes year after year. Decades-old infrastructure remains deeply embedded in the global financial system because, in many cases, it continues to perform reliably.

Each of these systems is designed for specific use cases. For financial institutions, PSPs, and global payment networks, the challenge is not choosing one over another, but determining how to use them together.

In other words, when we talk about issues caused by legacy payment infrastructure, we aren’t really talking about age, but rigidity.

How ISO 20022 is exposing operational rigidity

As payment ecosystems grow more diverse, institutions face increasing pressure to operate across multiple messaging standards, settlement tools, and regulatory environments  simultaneously.

Infrastructure becomes increasingly difficult to scale when it cannot adapt to new challenges. That could be changes in message formats, routing efficiently across different rails, or integrating new settlement models like stablecoins without significant re-engineering.

The path to reliable global payments runs through building flexibility into how systems connect, translate, and route across the technical, liquidity, and compliance layers. 

The International Organization for Standardization 20022 (ISO 20022) migration is bringing that distinction into sharper focus. ISO 20022 is often described as a messaging upgrade.

In practice it is something broader: a test of how interoperable payment infrastructure has actually become.

The transition introduces richer, more structured transaction data designed to improve transparency, strengthen compliance screening, and support more efficient reconciliation across payment networks. 

For cross-border payments specifically, the standard has real potential to reduce the manual intervention that continues to slow correspondent flows and inflate operational costs.

Across the industry, institutions have approached ISO 20022 in different ways. In some cases, the focus has been on meeting migration timelines by converting existing message formats into new structures, while leaving underlying routing, liquidity, and compliance frameworks largely unchanged. 

That approach may achieve regulatory compliance, but it does not, on its own, create more adaptive payment infrastructure.

The real value of ISO 20022 lies less in the format itself than in the interoperability it enables across diverse rails. 

A shared messaging standard creates the foundation for more intelligent routing decisions, faster exception handling, and stronger straight-through processing. 

ISO 20022’s structured remittance data can reduce the manual intervention that slows correspondent flows, but only where institutions have built systems flexible enough to use it dynamically.

ISO 20022 is exposing a divide that has been building across the industry: the difference between infrastructure that can evolve and infrastructure that continues to operate without adapting.

Why fragmentation is a permanent feature of global payments

Cross-border payments are often discussed as though fragmentation is a problem waiting to be solved. In reality, fragmentation is an inevitable feature of the global payments ecosystem.

Domestic real-time payment schemes, mobile wallets, card networks, correspondent banking systems, and emerging digital asset rails each serve distinct market, regulatory, and consumer requirements. The ecosystem is becoming more diverse, not less. The future depends on institutions being able to operate effectively across many of these systems at once.

A payment may move instantly within one network but slow at the boundary of another. In many cases, friction emerges where the connecting infrastructure cannot adapt in real time, and cannot route, translate, or coordinate information dynamically across different environments. 

In increasingly fragmented payment ecosystems, institutions also need greater operational optionality such as the ability to choose rails dynamically based on the needs of a transaction, whether it is prioritising speed, cost efficiency, liquidity optimisation, market reach, or resiliency.

The same principle applies to liquidity management. Pre-funding balances across multiple markets remains a common operational model for supporting cross-border flows. 

However, trapped capital is often not an inherent feature of international payments. It is a rational response to limitations in how liquidity can be allocated across currencies and corridors.

This creates a direct and measurable cost for treasury teams, as capital remains fragmented across markets instead of being deployed where it is most needed.

Institutions that can route dynamically across rails, translate between message standards, and manage liquidity centrally rather than in silos, are better positioned to absorb fragmentation rather than be constrained by it.

The growing importance of adaptive, multi-rail infrastructure

Connecting to more rails, markets, or settlement systems is only the first layer of modern payment infrastructure. The greater challenge is ensuring those connections can adapt as standards evolve, new corridors open, and settlement models change.

Broad connectivity without underlying flexibility can delay, rather than resolve, structural constraints.

Sustainable scale depends on three interconnected capabilities working in alignment.

• Technical orchestration: Dynamically routing across payment rails, supporting multiple message formats, and translating information efficiently between systems.
• Liquid flexibility: Moving capital intelligently across currencies and markets instead of fragmenting it across siloed pre-funding structures.
• Compliance agility: Maintaining consistent screening, monitoring, and reporting across jurisdictions while keeping pace with rising transaction speed expectations.

Each layer reinforces the others. Remove one layer and gaps start to show. Together, they determine how effectively an institution absorbs complexity without passing operational friction on to customers or partners.

This becomes particularly important as new settlement infrastructure continues to emerge. 

Regulated stablecoins, tokenised assets and alternative clearing models are expanding the range of payment environments institutions need to support. 

The question for any institution evaluating its infrastructure is not whether its rails are meeting its needs. It is whether its systems can adapt when the next standard, the next asset class, or the next market requirement arrives.

Why flexibility, not replacement, will represent the future of payments

The payments industry has long treated infrastructure replacement as the primary route to upgrading. But replacing rails does not eliminate friction when rigidity remains embedded in the routing, liquidity, and compliance layers above them. 

The limitations of that approach are becoming clearer.

ISO 20022 offers an opportunity to approach modernisation differently. Institutions that use the transition to build flexible, interoperable infrastructure are better positioned to operate effectively in an environment where complexity is already the norm.

Global payment ecosystems will continue to evolve across multiple rails, standards, and settlement models simultaneously. The institutions best positioned for long-term scale will not necessarily be those operating the newest infrastructure, but those capable of adapting as the ecosystem continues to change.

Inflexibility is the operational cost that fragmented infrastructure places on every transaction. Reducing that cost is no longer only an operational priority. It is becoming a strategic one.

Contact us to explore how Thunes can help you unify payment rails, liquidity, and compliance as you scale globally.