Datachain Opens Testnet Access to the KuraPrivacy Service API; Kura Pay Demo App Lets Partners Try Private Transfers

Tokyo, July 29, 2026 — Datachain, Inc. today announced testnet availability of the Service API for KuraPrivacy, its enterprise-grade on-chain privacy infrastructure. The Service API allows payment service providers and wallet operators to embed private transfers directly into their own products. Alongside it, Datachain is making Kura Pay — a browser-based demo application that exercises KuraPrivacy's core capabilities — available to partner companies.

Why Payments and Wallets Need Privacy

On a public blockchain, counterparties, transaction amounts, and account balances are visible to anyone. For corporate customers and institutional investors, that lack of confidentiality is a reason not to transact on-chain at all — and for payment and wallet providers, it has stood in the way of capturing enterprise demand.

Anonymizing everything is not the answer either. An approach that leaves no room for audit or issuer oversight remains difficult to deploy in production. KuraPrivacy is therefore designed to deliver privacy and regulatory compliance together, combining selective disclosure — shielding transaction data from third parties while revealing it to designated parties — with compliance controls such as restrictions on who may transact and policy-based forced transfers.

What the Service API Makes Possible

With the KuraPrivacy Service API (currently testnet only), providers can add the following capabilities to their payment and wallet services:

• Transfers from any wallet with a shielded recipient. Payments originate from an ordinary wallet while the recipient stays confidential. The sender's address and the amount remain public on-chain; only the receiving private account is hidden. This suits cases such as in-store payments, where identifying the payer is acceptable but linking the payee is not.
• Fully private transfers. When both parties hold private accounts, the sender, recipient, and amount are all shielded from third parties. Beyond hiding who sent how much to whom, this also prevents observers from linking multiple transactions to trace the flow of funds.
• Selective disclosure for audit and accounting. Issuing a viewing key grants a designated party — an auditor or a finance team, for example — read access to transaction history and balances within a defined account scope, without granting any transfer authority. Viewing keys are read-only; moving assets still requires separate approval with a signing key. The design is not "visible to no one" but "you choose who can see."
• Compatibility with existing wallets and authentication methods. KuraPrivacy supports the authentication and signing methods already in use, including EOAs, WebAuthn/passkeys, and contract wallets (multisig included). Because these existing keys can authorize ZK proofs as-is, providers can add privacy without rebuilding their authentication stack.

These are examples rather than a complete list. The Service API also supports allowlist- and denylist-based transfer controls, transaction history retrieval, and forced transfers. Full details are in the documentation:

https://docs.kura.datachain.jp/service-api

A developer SDK that makes the Service API simpler to adopt is planned for a future release.

Kura Pay: Seeing the Capabilities in Action

Kura Pay is a demo application that runs KuraPrivacy's core capabilities in the browser, making it possible to see exactly what is shielded and what stays public through hands-on use.

Kura Pay covers:

• Deposit. Move stablecoins and other assets from a public chain into a private account. The destination is shielded from third parties.
• Transfer. Send funds with the sender, recipient, and amount all shielded. Only the fact that a transaction occurred is recorded on-chain.
• Withdraw. Withdraw to any public address while keeping the source account confidential.
• Viewing key access. Grant read access to transaction history and balances to designated parties only, such as auditors or a finance team.

Working With Datachain

Datachain is offering Kura Pay together with testnet access to the Service API to companies interested in stablecoin-based payment and wallet services. Topics we are glad to discuss include:

• How KuraPrivacy would fit into your service, and what the result would look like
• Service API specifications and usage, including the forthcoming SDK
• Running a joint proof of concept
• The path and timeline toward commercial deployment

Contact

• Email: contact@datachain.jp
• Form: https://kura.datachain.jp/contact

About KuraPrivacy

KuraPrivacy is an enterprise-grade on-chain privacy infrastructure that delivers privacy protection and regulatory compliance together. It shields transaction data that would otherwise be public on a blockchain, while providing compliance controls including selective disclosure to designated parties, allowlist- and denylist-based transfer controls, and policy-based forced transfers.

• Website: https://kura.datachain.jp/
• Documentation: https://docs.kura.datachain.jp/

About Datachain, Inc.

Guided by its purpose — enabling the world to interact transparently as one network — Datachain builds on blockchain R&D conducted since its founding in 2018 to advance the real-world deployment of next-generation financial and payment infrastructure, across stablecoins, tokenized deposits, enterprise Web3 wallets, cross-chain infrastructure, and privacy infrastructure.

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