Loading...
Supporting developers, startups, and full-fledged companies building on Stellar and Soroban
© 2025 Stellar Development Foundation
Subscribe to the Newsletter
By Arculus x Stellar: Payments With Soroban
Arculus enables stablecoin or token holders on Stellar to pay at any Visa/MasterCard merchant, directly from self-custody wallets, utilizing Soroban smart-contracts.
PRODUCT
Utilizing Soroban, Arculus will write the smart contract that will allow holders of stablecoins (and potentially other tokens) on Stellar to use those funds at any merchant worldwide that accepts Visa or MasterCard. This solution allows for payments directly from a self-custody wallet with the consumer not giving up ownership until the moment of spend.
PROBLEM
Cold storage, while highly secure for storage of crypto assets, are often not ideal for a transactional experience. Arculus has already solved this issue with our next-gen hardware wallet that combines the security of cold storage with the usability of a hot wallet.
Currently, the practical utility of using cryptocurrencies in daily commerce, where speed and convenience are paramount, leaves much to be desired.
Most merchants do not accept direct payment in tokens or stablecoins; most merchants still want fiat currency. At the very few merchants that do accept digital asset payments, it is a slow process of QR codes, deep-linking, or double checking addresses. In short, it is a slower, more difficult process for both consumers and merchants.
Arculus is making it possible to bridge the gap between consumers with digital assets and traditional merchants by extending the unique transactional features of our cold-storage ecosystem - using Soroban smart contracts to connect self-custodied assets to traditional card payment rails. Arculus with Stellar makes it simple and efficient to pay from cold storage with Stellar tokens. That means meeting the current most popular methodology (VISA/MC Card Tap-To-Pay at POS terminals) where its at.
SOLUTION
Arculus is no stranger to the world of traditional payments. Arculus is created by Composecure, which for the past 20 years has been the world's leading manufacturer of metal payment cards.
Utilizing Stellar's new smart contract platform, Soroban, we will write smart contracts that allow fiat payments from self-custody & cold storage utilizing USDC on Stellar. This functionality will be demonstrated through simulated payment transactions with USDC on testnet and mainnet, as a real world payment scenario would require a licensed transmittance of payment to the merchant acquirer via Visanet. This paves the way for many different entities to adopt the smart contract and use in their own localities, for their own models, with their own remitters (Scaleable B2B Soroban Crypto to Fiat functionality with Stellar Anchor integration).
In practice, the smart contract logic would be loaded onto the chip on a card that's also loaded with a Visa or Mastercard applet. A user would tap to pay at any point of sale terminal, and it would act just as a normal fiat tap-to-pay transaction would, except the balance would be deducted from their cold-storage wallet.
**Although USD is the dominant backing currency for stablecoins today, this same solution can work as non USD stablecoins on stellar for this solution.**
WHAT PROBLEMS DOES THIS SOLVE?
This has the potential to solve many issues in a variety of use-cases. Most notably, and obviously, this greatly increases the real world use case of crypto assets - in this case, Stellar. Allowing people to spend their crypto assets in a way that is familiar and as easy as what they already do every day.
_Stellar-Aid Example: _Distribute Stellar-Aid branded cards that have this smart contract logic loaded - and can receive aid disbursements. Users of this card will be able to immediately utilize the aid, and eliminate Steps 3 and 4 of the Stellar-Aid Workflow, allowing for faster and more simple access to much-needed aid.
Overall, this project solves the problem of current clunky and slow processes of paying for goods or services with crypto assets, and brings the usability to the current premium accepted methodology.
Yes
$148.4K
Make USDC on Stellar as transactional for consumers around the world as fiat. Through B2B Partners, global consumers will start using stablecoins or tokens on the Stellar blockchain for day-to-day real world payments, and continue to store value onto the Stellar Blockchain as a hedge against inflation.
Our go-to-market strategy is to bring on B2B partners that are already active in the crypto-space or in card payments, and bring them the efficiency and speed of payments on Stellar. Arculus is already working with Moneygram as an on and off ramp for USDC on Stellar. Additionally, we see the potential for a remittance card product that allows consumers to more easily access their USDC on Stellar. We also see a very valuable use with Stellar Aid-Assist, where Aid recipients could directly send or spend Aid funds anywhere that accepts Visa or Mastercard. This use case would reduce the need for Aid-Assist recipients to obtain local fiat.
https://polygonscan.com/address/0x389c6f04d39ff038cc99f94bce338d2f5eb64a67#code
The above link showcases the current smart contract operating on polygon that we have loaded onto VISA/MC payment cards and successfully uses USDC on Polygon contained in the Arculus wallet to purchase goods and settle in local currency.
This functionality is displayed in the Pitch Video Link.
[Develop Soroban Collateral #1 - Controller] a. There are two contracts, the controller contract and the collateral contract. There will be a single instance of the controller contract (owned by an administrator). It deploys an instance of the collateral contract for a particular user. The controller contract also invokes operations in the collateral contract. b. Completion for this milestone is validated by the completion of the second milestone, when the controller deploys the instance of the collateral contract and invokes given operations in the collateral contract. c. 10/15/24 d. $50,500
2\. [Develop Soroban Collateral #2 - Collateral]
a. Developed in tandem with the Controller contract. There will be an instance of the collateral contract for each user. The user "owns" the collateral contract but cannot perform operations on it directly. The collateral contract holds a balance of crypto assets. It also tracks a spent amount for each asset, which limits the amount the user can withdraw.
b. Completion for this milestone is validated by the completion of the first milestone, when the Collateral contract and it's operations are invoked through the Controller contract.
c. 10/15/24
d. $42,300
3\. [Develop Operations Architecture]
a. There are four main operations. These operations are invoked by the UI on the controller contract and must be authorized by the administrator. The controller contract will then invoke the corresponding operation on the collateral contract. The collateral contract will only allow operations initiated by the controller contract. The four operations are described below.
- Spend: Spend some amount of a particular crypto asset. The administrator initiates this operation when the user performs a spend operation in the financial arena, such as a purchase using a card. If there is a sufficient balance in the asset, the collateral contract increments the spent amount for that asset. - Payment: The administrator initiates this operation when the user makes a payment to pay down the outstanding balance. This reduces the spent amount of the appropriate asset. - Withdraw: The user requests to withdraw the collateral balance to another crypto account. The user may withdraw the balance of the asset minus the spent amount. - Liquidate: The bank seizes the collateral assets. The spent amount of the appropriate asset is sent to the bank's treasury account.
b. Completion for this milestone is validated by initial testing of the Soroban Collateral, where invoking the controller contract, authorized by the admin, invokes corresponding operations on the collateral contract. This milestone requires testable functionality of the first two milestones.
c. 10/30/24
d. $36,800
1\. [Deploy Initial Smart Contracts on Testnet]
a. Activate Controller and Collateral smart contracts on Soroban's sandboxed test network.
b. Completion for this milestone is validated by the successful upload of both smart contracts to the testnet.
c. 11/2/24
d. N/A
2\. [Conduct Bug Testing and Fixes]
a. During testing of the functionality of the smart contracts, De-Bug as necessary.
b. That any bugs encountered are eliminated and the smart contracts move toward a smooth as intended experience.
c. 11/30/24
d. N/A
3\. [Test network load and scalability]
a. Ensure the system can scale efficiently and perform under heavy usage without issues before going live.
b. Review logs and metrics from the test runs to see real-time data on how the system performed under stress. Cover various levels of transaction volumes and user loads and ensure these test scenarios hold up. Make fixes as necessary.
c. 12/15/24
d. N/A
4\. [Final Security Internal Review]
a. Code Review - Testing and Validation - Compliance Check - Sign Off.
b. Ensure that all testing and verification passes tests flawlessly. These checks include static analysis, logic verification, unit testing, integration testing, penetration tests, compliance review, detailed report, and final sign off for approval of readiness for Mainnet launch. This final testnet milestone ensures stabilization.
c. 1/12/24
d. N/A
1\. [Mainnet Preperation]
a. Develop a deployment plan outlining the steps and timing for the mainnet launch, and confirm that all infrastructure components are ready and properly configured for Mainnet operation.
b. Completion for this milestone is validated by ensuring that the deployment plan aligns with the goals of the project fully, and that infrastructure components are tested and configured properly.
c. 1/30/24
d. $8,500
2\. [Mainnet Launch]
a. Deploy the smart contracts to the mainnet according to the deployment plan.
b. Launch and monitor the system closely for any issues or anomalies immediately following deployment.
c. 2/3/24
d. $10,300
3\. [Post-Launch Activities]
a. Ongoing monitoring to ensure the system operates smoothly and detects any unexpected issues early. Determine and document scope for consumer launch requirements (External Audit, etc.) Research development requirements for Non-USD Stablecoin support in this model.
b. Perform monitoring, asset monitoring infrastructure & dashboard development, future development research, determine audit budget and requirements.
c. Ongoing & Periodic
d. N/A
The core team on this project consists of around 5 members. Besides building an entire cold storage wallet ecosystem - We have built a working product that is identical in function to the project proposed in this application on the polygon network, and are ready to start building on Soroban.
Jonah Johnson
No other submissions.