Singapore PayNow and FAST

Singapore is often cited as a model for modern instant payments, and its system is a clean example of a pattern seen worldwide: a fast settlement rail underneath, and a proxy addressing layer on top that makes it easy to use. Those two pieces are FAST and PayNow, and understanding how they relate clears up a lot of confusion.

FAST: the underlying rail

FAST (Fast And Secure Transfers) is Singapore's real-time interbank credit-transfer rail. It lets customers of participating banks and non-bank financial institutions send funds to one another almost immediately, around the clock. FAST is the plumbing: it moves money between accounts in near real time and is available 24/7, replacing the wait of older batch transfers.

On its own, FAST still requires the sender to know the recipient's bank and account number. That works, but it is clumsy and error-prone, especially for person-to-person payments.

PayNow: the addressing layer

PayNow sits on top of FAST and solves the addressing problem. It is a proxy service that lets you send money using a simple identifier instead of account details. Supported proxies include:

• A mobile phone number.
• An NRIC/FIN (national identity number) for individuals.
• A Unique Entity Number (UEN) for businesses.
• A virtual payment address for certain use cases.

Behind the scenes, PayNow maps that proxy to the registered bank account and routes the payment over FAST. The payer never needs the account number; they just need the recipient's phone number or ID. This is the same conceptual pattern as India's UPI virtual addresses or the euro area's proxy lookups — a human-friendly layer over a machine rail.

Why the split matters

Keeping the rail and the addressing layer separate is good design. FAST handles movement and settlement; PayNow handles identity and convenience. Improvements to one do not require rebuilding the other. It also means a payment initiated through PayNow is really a FAST transfer under the hood — the speed and finality come from FAST, while the ease of use comes from PayNow's proxy resolution.

For businesses, the UEN proxy plus PayNow QR (aligned with the national SGQR standard) enables quick merchant payments: a customer scans a code, their app resolves the merchant proxy, and the funds move over FAST. This underpins much of Singapore's QR-based retail payment experience.

Going cross-border with linkages

Singapore has pioneered cross-border linkages that connect PayNow to other countries' proxy systems. The landmark example is the PayNow-PromptPay linkage with Thailand, which lets users in each country send money to the other using just a mobile number, with funds moving quickly and at lower cost than traditional remittance. Further linkages, including work connecting PayNow with India's UPI, extend the same idea.

These linkages are significant because they show how domestic instant rails can be interconnected without building a whole new global system: each country keeps its own rail and proxy scheme, and a bridge translates between them. It is a template many regions are now pursuing for faster, cheaper cross-border retail payments.

How registration and routing work

The convenience of PayNow rests on a registration step. To receive money via a proxy, a person or business links their chosen identifier — a mobile number, NRIC/FIN, or UEN — to a specific bank account through their bank. That mapping lives in a central proxy directory that participating institutions query. When someone sends to a proxy, the system looks up the registered account and returns the recipient's registered name so the payer can confirm they are paying the right person before committing. That name-confirmation step is a built-in defence against mistyped payments and a form of payee verification.

A person can register different proxies to different accounts, and only one account can be tied to a given proxy at a time, which keeps routing unambiguous. If someone changes banks, they re-point their proxy, and future payments follow automatically — the payer never has to learn a new account number. This indirection is exactly what makes proxy-based systems resilient and user-friendly compared with raw account-number transfers.

Key takeaways

• FAST is Singapore's 24/7 real-time interbank credit-transfer rail — the underlying money movement.
• PayNow is a proxy addressing layer on top of FAST, letting you pay to a mobile number, NRIC/FIN, or UEN.
• Separating rail from addressing lets each evolve independently; a PayNow payment is a FAST transfer underneath.
• UEN proxies and PayNow QR (via SGQR) enable fast merchant payments.
• Cross-border linkages like PayNow-PromptPay connect national proxy systems for cheaper remittances.