Bounce: A NFC card solution to payments based on PoS terminals

Project Name: Bounce
Project Track: Web3
Team Name: The Bounce Team
Team Member(s): (2) @mangoquarterzip @wubruno
HackerEarth Project Link: newliukev_5cef - HackaTRON Season 5 - Published | HackerEarth Hackathons

Video Link:
Project Goal: Bounce offers peer-to-peer, non-custodial NFC card payments with PoS terminals.

Project Value:

In countries with high inflation, holding onto the native currency becomes financially detrimental. Take Venezuela, currently experiencing hyperinflation with rates exceeding +300%. Imagine depositing 100 dollars in a bank only to find it reduced to a value of 25 dollars within a year.

Within our industry, we recognize that stablecoins, be it centralized ones like USDC and USDT or newer options like GHO or crvUSD, can be a solution. But merely advising people to purchase and retain stablecoins isn’t enough. The real challenge lies in establishing a practical payment system where vendors accept these stablecoins. One major hurdle is the current user experience in crypto transactions. Even for seasoned crypto users, the process is cumbersome. Conversations often go like: “What’s your address?” "It’s 0x23jdf8…” “Could you share it on Telegram?” “What’s your Telegram?” “Shall I scan you or vice versa?” “I’ve shared my address.” “Let me transfer it to my wallet app.” “Just a moment, I need to calculate the Venezuelan Bolivar to USD rate.” “Alright, it’s processing now.” This involves navigating through multiple apps, numerous clicks, and considerable time to complete a single transaction.

Our technology and implementation allow us to supply vendors with PoS terminals, which henceforth allows their customers to make payments in stables easily.

Project Info: tron_hack.pdf (328.7 KB)

Project Test Instructions: {setup instructions}

Smart Contract links:

Vault Factory: TRONSCAN | TRON BlockChain Explorer | 波场区块链浏览器
Vault: TRONSCAN | TRON BlockChain Explorer | 波场区块链浏览器
PoS Terminal: TRONSCAN | TRON BlockChain Explorer | 波场区块链浏览器


Once more, another one in the web3 track.
Creating a peer-to-peer, non-custodial NFC card payment solution utilizing PoS terminals that addresses the challenges of inflation by providing a practical payment system using stablecoins is really a way to go. As smooth as it sounds, I’m only curious about one thing and I’d like to be clear on it, how would you overcome regulatory hurdles related to stablecoin usage and transactions?


Bounce can also make a credible impact by working to improve the overall user experience of crypto transactions.
This could involve developing new technologies or protocols that make it easier and faster to send and receive crypto payments. It could also involve working with other crypto companies to create more user-friendly wallets and payment solutions.

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Welcome to Hackatron S5, just as @manfred_jr asked how do you overcome these regulatory issues? Do you have targeted countries?


Hi @manfred_jr , @Okorie , @Prince-Onscolo ,

Thanks for all of your questions.

In regards to a regulatory standpoint, we face minimal issues. The currency of which we transact with does not have to be obligatorily stables, it could be WBTC, or it could be TRX, of which we know are decentralized tokens. Even if it was stables such as USDC, or USDT, we still do not face issues as these tokens are NOT ISSUED BY US. It’s not something like PYUSD where Paypal has issued their own stablecoin, BOUNCE is simply facilitating the exchange and transfer of these tokens. In essence, Bounce’s systems could be compared to just a wallet like Metamask, or Tronlink wallet. They both facilitate the same function, which is to allow the transfer of tokens.

Hope that answers your questions!

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Thank you for providing additional insights regarding my question on regulatory standpoint, clearly from your explanation, Bounce acts as a facilitator for the exchange and transfer of tokens, enhancing user experience in the crypto transaction process. But hmm, that comparison of Bounce’s systems to existing wallets like Metamask or Tronlink I think it’s a little way off and I’d put you in the spot, why would I cast a vote for Bounce over MetaMask or TronLink?

NFC cards for crypto transactions is new to me, and I need as much clarity on it to be honest, how would you educate and raise awareness among potential users about the benefits and functionalities of using NFC cards for crypto transactions?
Thank you!


Welcome to Grand Hackathon Season 5 wishing you all the best


Hey, thanks for your followup question. The elevator pitch for this project is mainly a pitch for UX. With stronger UX, we lead to stronger adoption of day to day use of crypto payments.


Thanks for replying, you’ve offset my curiousity at this point, kudos!

Nice project and welcome to season 5.

We all know to attracts agents of POS, there should be a form of payments to these agents. (I stand to be corrected)

If that be the case, what will be the cost involved in dealing with these POS agents and how are you going to ensure that some agents are not charging exorbitant prices maybe due to monopoly.

Thank you

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Thanks for your question. Assuming that your meaning of an agent is a vendor, i.e. someone that operates a PoS terminal. There are multiple routes that we can take to incentivize vendors to use our systems.

Just as an example, if there is a chain of bubble tea shops in Venezuela, we can ask the management of the shops whether they would be willing to use our system. And in return, we would rebate their customers (kind of like a sponsorship), on their bubble tea purchase. E.g. if a customer buy a bubble tea for 1.5 dollars, and we rebate them 1 dollar, if they sign up to use our card, app and also make payments with the PoS terminal, our user acquisition cost per customer/user is 1 dollar! In comparison: it’s commonly known that CEXs like Coinbase or Binance will often run promotions such as: “refer one friend, and we’ll reward you 10 dollars in BTC!”, in their case, their user acquisition cost is 10 dollars per user! If it costs Bounce, 100,000 dollars to acquire 100,000 users, honestly, we don’t mind!

In terms of your question for monopoly, I’m not sure whether that line of questioning strictly applies to our project, how can there be a monopoly from the vendor side? If they would normally charge, 1.5 units of currency when receiving payment in fiat, why would they choose to hike the prices when charging through crypto? It just doesn’t make sense.

Hope that answers your questions!


I get your explanation very well. I used monopoly as we have mobile money vendors in Ghana, sometimes there is only one person in a locality and when that happens, when you send money to another person through that vendor, he charges you a fee, meanwhile sending money shouldn’t cost anything.

But since he is the only vendor around, u pay it bit when there are several vendors in a locality such tin is not seen anywhere.

This was the main reason i made mention of the monopoly but from your explanation i get what you mean now. Thank you


I enjoyed your example of how people can communicate when attempting to send money with today’s current apps. It is definitely a struggle! Does your NFC card integrate with any other main wallets such as MetaMask or TRONlink?

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@mangoquarterzip Welcome to Tron Hackathon S5, Your idea looks great. I have few quaestions

  • How user is going to deposit USDC to his NFC Card ?

  • How about other currencies like TRX, USDD. Are you planning to implement these conversion as well ?


You think its not cool to have various projects on web3?

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I actually think it is cool buddy, thanks for asking.

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Hey Steven, thanks for the question.

We didn’t manage to showcase it in the demo video, but we have a mobile app in production, which in turn, connects to TronLink, allowing users to deposit funds!


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Thank you for sharing. I am reviewing this project with the video, the slides and versus existing work that was done for Eth Global Bounce | ETHGlobal

This project is a point-of-sale payment solution using temporary keys on a payment card and with risk-based dollar-amount limits across different retailers. I like the risk limiting approach.

For this Season 5, the contribution was to adapt this project to TronLINK and Tron payments for the existing product. This project is a commercially valuable, high-effort project, so I welcome such an incremental improvement as in-scope for this S5.

Looking great, keep it up!


I did not understand why you did the swap at the end but I guess is to avoid currency hyperinflation.

In all of the logic I seem to miss how to get the money out of the POS :slight_smile:

For me, the contract seems to lack a withdrawal function.

Congrats on the work,
onchaindev :white_heart:

You are welcome :slight_smile: I also think its cool to have more and more projects on different categories