Open debit card for developers powered by Kusama

Summary

An Open API that lets developers issue prepaid debit card functionality to their platforms at almost no effort and store its value in Kusama.

TL; DR

Resources

• Full proposal document.
• Website.
• First customer Coco Wallet YCS19 and letter of intent for 450K and 3,500 Users.
• Contract with Visa & Pomelo to issue debit cards, please request via DM in @david:bloque.team in Element.
• Preview API Documentation.

How it works

Comparison with current alternatives

Partners

• Pomelo + Visa (Debit card issuer): Pomelo is a pioneering fintech transforming card issuance in Latin America. Its cloud-native, API-driven platform lets banks and fintechs launch secure, scalable cards rapidly. Partnering with Mastercard and Coastal Community Bank, Pomelo modernizes payments and drives financial inclusion.
• Truora (KYC/KYB): Truora is a Latin American startup simplifying user verification and fraud prevention. Its API-driven platform offers background checks, digital identity, and KYC tools to help businesses onboard customers securely, reduce fraud, and boost conversion
• Bancolombia (Our Bank): Bancolombia is Colombia’s largest bank, boasting 146+ years of trusted service. With 30M+ customers, extensive branch and ATM networks, and innovative digital solutions, it drives financial inclusion, supports sustainable growth, and champions economic progress across Latin America.

FAQ

• Why funding us? We are an experienced team with a proven record of building Web3 products. Now, we want to use Kusama in everyday cases worldwide.

• Which regions are supported? Mainly LatAm starting in Colombia & Mexico with worldwide availability via Passport.

• How will this API handle key material since the wallets are non-custodial?
  We use a combination of proxy accounts with defined spending limits. In addition, the “debit callback” endpoint with 3D Secure prompts users to authorize (i.e., sign) transactions—effectively meaning the user “sells” crypto to us so that we can complete the payment on their behalf. Our security model is based on Shamir’s Secret Sharing: at setup, the holder sends us one part of the secret while keeping the other part secure across multiple devices. When a transaction is authorized, the two parts are combined to complete the transaction.

• How are redemptions processed?
  Today’s redemption channels include Brale Rails (conversion across 10+ chains to USDT/USDC), a DEX liquidity pool for KSM/dUSD, and direct debit card transactions.

• Do day-to-day COP inflation swings pose a risk?
  Yes, they can. To mitigate this risk, we maintain only small COP buffers in the bank while holding most of our treasury in USD.

• How will the system mitigate potential volatility given that settlement can take several days?
  Limiting USD buffer sales to twice daily (e.g., morning and afternoon) may expose us to unexpected volatility. Ideally, we offload USD as frequently as market conditions allow. When that isn’t feasible, we rely on compensation accounts, short-term COP buffer loans, SWIFT transfers, and OTC channels to quickly convert USD into COP liquidity.

• How would a chargeback or clawback be handled?
  For same-day chargebacks—such as paying $5 with KSM for an Uber ride and then canceling—the system applies an adjustment credit by deducting $5 from the USD buffer, converting it to KSM, and crediting your account. For delayed clawbacks—like purchasing a $20 card with KSM on Temu but receiving a faulty product—we detect the issue via Visa’s invoices and balance sheets. In the next payment cycle, we net the amounts between our accounts; for instance, if we owe Visa $100 but receive $20, we pay only $80, converting the extra $20 into KSM and crediting your account.

• Whats the relationship with Virto? BloqueDAO is a Virto-spinoff established as a self-governing DAO in Kreivo. We’re leveraging on the Kreivo technology to support non-custodial management of the funds every user tops-up in their Kusama Pay cards.