Building a Secure and High-Performance Stablecoin Fund Management and Payment Infrastructure

Client Overview

The client is a global stablecoin payment card issuer providing virtual and physical card products funded by stablecoins such as USDT and USDC. These cards are accepted across Visa and Mastercard networks for online and offline spending, subscription payments, advertising account binding, and other everyday use cases.

On one side, the issuer connects cardholders with their on-chain stablecoin assets. On the other, it integrates with licensed issuing banks, card networks, and clearing institutions. Its core value proposition Its core value proposition is the secure, compliant, and reliable conversion of on-chain stablecoins into usable card balances.

Business Challenges

• Security and operational barriers to digital asset custody: User top-up funds form the underlying prepaid balance pool for card spending. Building an in-house wallet infrastructure introduces significant single-point private key risks and requires substantial investment in hot–cold wallet separation and HSM-based security architectures.

• Real-time multi-chain aggregation requirements: End users top up across multiple public blockchains, including TRON, Ethereum, and BSC. The system must detect on-chain deposits and update card balances in near real time. Any delay directly degrades the cardholder experience.

• Stringent KYT/AML compliance requirements: Every inbound and outbound fund transfer must undergo AML screening and on-chain KYT monitoring to meet the requirements of card networks and regulators.

• Infrastructure lock-in considerations: Once deposit addresses are issued at scale to end users, migrating wallet providers becomes operationally risky and costly. The issuer required a long-term infrastructure partner capable of supporting growth from early-stage deployment through large-scale global operations, avoiding repeated system rebuilds.

Cobo’s Solution

• Enterprise-grade full custody with multi-chain support: Cobo established a bank-grade, fully custodial fund pool for the issuer. Stablecoin deposits across all major public blockchains are supported. Using large-scale address generation capabilities, each card or user is assigned a dedicated deposit address, enabling automated fund aggregation and tagged fund management.

• Unified fund management and payment orchestration: By integrating Cobo’s WaaS API, Payments API, and webhooks, the issuer achieved seamless connectivity with its card issuing core system. Upon deposit confirmation, Cobo triggers real-time callbacks to update card balances automatically. When card transactions occur, APIs are invoked to transfer funds accordingly, with the entire process executed end to end without manual intervention.

• Built-in compliance firewall: Cobo integrates compliance and risk controls across the full fund lifecycle. The system applies on-chain KYT monitoring based on predefined risk policies and screens all funds moving within the custodial environment. Transactions associated with sanctioned entities or high-risk labels are automatically restricted and escalated for review, ensuring fund source transparency and audit-ready traceability for the card program.

Results and Impact

• Stronger asset security and compliance readiness: Stablecoin assets are centrally custodied within Cobo’s wallet infrastructure, with private keys never circulating within the issuer’s internal systems. Combined with KYT/AML screening and structured mechanisms for handling anomalous funds, this provides clear and auditable fund flows to support compliance engagement with card networks, regulators, and partner banks.

• Improved card top-up and settlement efficiency: Multi-chain, multi-asset deposits are credited automatically, with card balances closely synchronized to on-chain confirmations. Manual reconciliation and settlement delays are significantly reduced, while upstream and partner settlements can be planned using a unified, real-time fund view.