Financial interoperability

The Committee on Payments and Market Infrastructures at the BIS defines interoperability as the technical, semantic and business compatibility that lets participants in different systems conduct, clear and settle transactions across systems without participating in each of them. Technical compatibility means that two systems can exchange data at all. Semantic compatibility means that both read a field such as the payer or the settlement date in the same way, and business compatibility covers access rules, finality and liability.

For a classic euro payment these questions were settled long ago: a standardized message carries the instruction, the banks keep the customer accounts, and the transfer between banks settles in central bank money. A tokenized bond adds a ledger that records the asset itself, and that ledger has to reach the messages banks already send and the money that pays for the bond. Interoperability projects in finance build exactly these three connections between ledgers, bank messages and settlement money.

ISO 20022 is the shared message standard of the euro area infrastructure: T2, the real-time gross settlement system of the Eurosystem, uses ISO 20022 in common with T2S, TIPS and the collateral system ECMS. The standard defines message families such as pacs for payments between banks and camt for account statements. Because most banks already produce these messages, the standard is the obvious entry point for connecting bank systems to tokenized assets.

In 2023, Swift tested with more than a dozen institutions, among them Citi, BNP Paribas, Euroclear, Clearstream and SIX Digital Exchange, whether a bank can reach several public and private blockchains through its existing Swift connection. Chainlink connected the Swift network to the chains and carried the transfers with its Cross-Chain Interoperability Protocol. At Sibos 2025, a pilot with UBS Tokenize showed that ISO 20022 messages sent over Swift can trigger subscriptions and redemptions of a tokenized fund. In November 2025, UBS then completed a live subscription and redemption of its uMINT money market fund token on Ethereum under the same Chainlink standard for transfer agents. Swift is also building a shared ledger for tokenized deposits next to its messaging services.

Between public blockchains, interoperability runs through cross-chain protocols such as CCIP, LayerZero, Wormhole and Axelar. Each of them carries a verified message from one chain to another, so that a token can be locked or burned on one side and issued on the other. The protocols differ in who confirms that the event on the source chain really happened, and that trust model is what a bank has to assess before it moves a regulated asset across chains.

Canton Network follows a different design for institutions: each participant keeps its own ledger, and a synchronizer coordinates only the parts of a transaction that the counterparties share. The Bank for International Settlements proposes a third model, the unified ledger, on which tokenized central bank money, tokenized deposits and tokenized assets sit on one programmable platform. Project Agorá tested that model with central banks such as the Banque de France and the Swiss National Bank and with more than 40 financial institutions. On one shared ledger a bank holds a single pool of tokenized money, while on several connected ledgers that money has to be bridged or held separately on each platform.

Since 21 September 2026, the Eurosystem service Pontes has linked DLT platforms with the TARGET Services, so a trade on a ledger can settle its cash leg in euro central bank money. The ECB announced on the same day that it will buy tokenized securities of euro area governments and supranational issuers for its own funds and settle them through Pontes. Pontes combines the three solutions the Eurosystem tested in 2024, among them the Trigger solution of the Deutsche Bundesbank, and the longer Appia track asks whether Europe needs one shared network or several connected ones.

The Swiss National Bank has issued wholesale central bank money on the SIX Digital Exchange platform since the end of 2023 under Project Helvetia. In June 2025, the SNB extended the pilot until at least mid-2027 and added a second route: BX Digital, a trading facility for tokenized assets, connects to the Swiss Interbank Clearing system, so tokenized assets can also settle against ordinary central bank money. The SNB plans to compare both routes in production before it decides how to proceed.

No single EU act regulates interoperability, so the obligations come from the rules for each system that a transaction touches. The Settlement Finality Directive protects the finality of transfers inside designated systems, which means a transfer that crosses into an undesignated ledger needs a contractual rule for the moment it becomes final. The DLT Pilot Regime has allowed market infrastructures to trade and settle tokenized securities on a ledger since 23 March 2023, and its DLT settlement systems are among the platforms that may connect to Pontes. Under DORA, which applies since 17 January 2025, a bank that buys connectivity to ledgers from a provider records that provider in its register of information and needs an exit plan for critical functions.

In Germany, the Electronic Securities Act lets issuers record bonds and fund shares in a crypto securities register, and keeping such a register requires a license from BaFin. Switzerland created ledger-based securities and a license for DLT trading facilities with its DLT Act, in force since 1 August 2021, and FINMA granted the first such license to BX Digital on 18 March 2025.

The CPMI names the risks of missing interoperability: platform operators may avoid links to keep market power, liquidity and securities get locked up across several platforms, and banks end up with bilateral connections and long transaction chains. When links do exist, the weak point is usually the verification step between two ledgers, where the largest bridge failures happened while the underlying chains kept working.

Interoperability in banking means that a bank can send a payment or a securities instruction to a customer of another bank, or to another system, without opening an account in every system. SEPA instant transfers show it in daily use: under the EU Instant Payments Regulation, banks in the euro area that offer credit transfers must also send and receive instant transfers in euro, so any account can reach any other within seconds.

Blockchain interoperability is the ability of one blockchain to act on a verified event from another, such as a token that was locked, burned or transferred there. For a regulated asset the deciding questions are who verifies that message and at which point the transfer becomes legally final on both chains.

In payments, interoperability means that payer and payee can use different banks, apps or card schemes and still complete the transfer. At the checkout, a phone wallet and a contactless card work on the same terminal because both follow the EMV contactless specifications, and between countries the G20 roadmap for cross-border payments asks national payment systems to link with each other.

No, ISO 20022 is a standard for the content and structure of financial messages and does not prescribe how a ledger stores them. ISO 20022 messages can still start actions on a blockchain, as the tokenized fund pilot of UBS over Swift showed, and the same message can then update the bank account and the token register.

CBDC interoperability connects central bank money in different currencies or on different platforms, so that a cross-border payment settles in central bank money on both sides. Project mBridge puts several central bank digital currencies on one shared platform, while Pontes connects existing DLT platforms to the euro central bank money that banks already hold in T2.