Vietnamese Payments App Prism Is Integrating Inco Lightning To Enable Confidential QR Payments

Cross-border payments are one of the clearest cases for putting money onchain. Stablecoins settle in seconds, move across borders without correspondent banks, and reach anyone with a phone. For the millions of people who travel, work, and spend outside their home banking system, that combination solves a real, everyday problem: how to pay a local merchant when you don't hold a local bank account.

But blockchains are transparent by default, which means every payment you make is visible to anyone with an internet connection. Pay a merchant onchain and you expose your balance, your transaction history, how much you spent, and where you spent it. For a consumer paying for coffee or a taxi, that's a worse privacy standard than the card already in their pocket.

With this in mind, Vietnam foreigner payments app Prism is integrating Inco Lightning on Base Mainnet to enable confidential payments.

What Prism Does

Prism is a self-custodial wallet that lets foreigners in Vietnam pay any merchant by scanning their bank QR code without needing a Vietnamese bank account.. A visitor tops up their wallet (bank transfer, card, or crypto), scans the standard bank QR a merchant already displays, and the merchant receives Vietnamese dong (VND). Prism holds a dollar balance powered by stablecoins, and users keep custody of their own keys and funds throughout.

Behind that simple experience is a payment flow designed to feel instant. The user signs a gasless authorization in the app, and Prism sponsors the gas, so there's nothing extra for the user to pay or manage. Prism's backend makes sure the transaction goes through, and a payment partner in Vietnam handles the payout to the merchant in VND. From the user's side, it's just: scan, confirm, done. 

Why Confidentiality is the Missing Piece

Everything above works on a transparent blockchain. Without a confidentiality layer, a Prism payment would leak exactly the kind of information a payment app should protect:

• Balances. Anyone could see how much a user holds.
• Amounts. Every payment amount would be public.
• History and patterns. Where someone pays, how often, and when — visible to anyone watching the chain.

This is the privacy gap that keeps consumer payments from moving fully onchain. Legacy payment systems keep this information private by default. To bring payments onchain without a step backward, the balances and transaction amounts need to stay confidential while the payment itself remains verifiable and final.

To solve this issue, Prism is integrating Inco Lightning, Inco's smart contract library for building confidential applications on public blockchains. With Inco Lightning, a user's balances and transaction amounts stay encrypted onchain, while the payment still settles and can be verified end to end. 

Concretely, the flow looks like this:

1. The user signs a gasless authorization inside the Prism app, with Prism sponsoring the gas.
2. Prism's backend confirms the transaction goes through.
3. A payment partner in Vietnam pays the merchant out in VND.
4. Throughout, balances and amounts remain confidential because they are encrypted with Inco Lightning.

Because Inco Lightning is a pluggable library rather than a separate chain, Prism didn't have to migrate anywhere or rebuild its stack. It integrates with the tools and infrastructure Prism already uses — embedded wallets, Base, and USDC — and adds confidentiality underneath. The result is a payment that settles onchain with the privacy properties users expect from the payment methods they already trust.

The integration is live on Base Sepolia today, and will launch on Base mainnet very soon.

Inco powers blockchains with fast, programmable privacy, protecting address and transaction details to unlock new use cases across payments, DeFi, gaming, governance, and more. Inco Lightning is live on Base mainnet and Solana Devnet.