DevPost Hackathon 2020

The Winners and Closing Ceremony

Published in

Harmony

7 min readOct 22, 2020

After spending a month working with 177 developers to build scalable dapps on Harmony, benefiting from our 5 seconds fast-finality and ultra-low-cost transaction fees, we are excited to announce the winners!

In total, 14 projects were submitted, and 10 deployed on mainnet. Winners were chosen based on four criteria:

Quality of Idea: This includes creativity, originality, and relevance to hackathon topics.
Implementation of Idea: which refers to how well the idea was executed by the developer and the quality of UI/UX.
Potential Impact: the extent to which the solution can benefit money remittances and international payments.
Deployment on Harmony Mainnet: whether the application was deployed on mainnet.

The top dapps submitted consisted of a cross-chain exchange for assets between Ethereum and Harmony using Chainlink oracles, a payment gateway integrating Circle API with Harmony, integration with Ripple’s PayID, and uncollateralized loans such as KIVA.

🥇 First Place: GoldenStarSwap

An Ethereum-Harmony cross-chain swap dapp that uses Chainlink Price Feeds to swap ETH or ERC-20 tokens into the native Harmony token ONE.

Goldenstar is built on three main modules including EthBridge, HmyBridge, and Relayer. In which the pricing of exchange tokens used through Oracle Chainlink is on Ethereum and Harmony.

EthBridge: Lock the number of tokens exchanged into the contract and calculate the value of the locked token at that time through Oracle Chainlink, emit Event Lock token for Relayer
Relayer: Subscription EthBridge to receive Event Lock and moderate them before transferring to HmyBridge
HmyBridge: Receive events from Relayer and parse the data, calculate the corresponding number of One through Oracle Chainlink located on Harmony and transfer amount One accordingly.
Inspired by the open-source https://github.com/harmony-one/ethhmy-bridge, the team has built a swappable proof-of-concept from ETH, ERC20 to One.

Architecture Diagram

What’s next for GoldenStarSwap?

Goldenstar swap is a demo of the product that the team is looking to build: Lending cross-chain. In the next versions the GoldenStarSwap will incorporate additional blockchains:

Tomochain (with native token Tomo)
Cosmos hub (with native token Atom) Build up an interface for the user to provide liquidity to receive farming tokens.

Check the video from the demo here, interact with GitHub repo here, or test the project.

🥈 Second Place Integrations with CIRCLE & USDC

The Web3Devs team wins second place. They built a fiat gateway using traditional credit card payments and interacting directly with the Harmony blockchain. The project used Circle API to fund a USDC wallet with custom backend API calls allowing the user to use a pool of ONE to be moved from a wallet to any other wallet.

You can check the demo video here, or learn more here.

🥉 Third Place Integrations with PayID Ripple

Aymeric Bethencourt won third place with the project 0 Games Evolution. 0Games is a peer-to-peer 0% fee CD Keys crypto-marketplace. You probably heard of G2A.com or Gamivo.com, these are CD Keys marketplaces where sellers can sell Steam CD Keys. These platforms are very popular with millions of visitors per month. However, they take up to a 30% fee! 0Games is here to lower that fee to zero.

The project integrates with Ripple’s PayID.

You can check the video demo here, check the GitHub repo, or transact on the Peer-to-Perr Game marketplace

🏆 Runner-UP Awards

Recycloan- Uncollaterized Lending

Recycloan, by Chris Buonocore & Brian Cottrell built a microlending for disadvantaged entrepreneurs without access to credit. Recycloan comprises a smart contract on the Harmony mainnet and a web application. The web application is built using React.js and the smart contract is built using Solidity. A loan can be initiated on the Recycloan smart contract using the lend function, which establishes a list of borrowers and funds the balance of the contract. The balance is immediately transferred to the first borrower. The repay function allows a borrower to repay the funds they were lent, and once the balance reaches the full amount lent, it is transferred to the next borrower.

Learn more about the project here: https://devpost.com/software/recycloan

Cashback- eCommerce Loyalty

Cashback is an e-commerce platform that allows users to purchase items for a refund in the form of HRC20. Each product will have a corresponding refund rate. After being reimbursed in HRC20 form, users can staking that amount of HRC20 to be able to Yield Farming to generate a corresponding ONE, after each day 2% of the HRC20 is converted to ONE. Therefore it will stimulate the user to buy so that it can increase the rate of pay normally. Users can withdraw the converted ONE at any time they want, however when withdrawing the HRC20 amount will be burned corresponding to the percentage of ONE withdrawn. This will stimulate users to staking the HRC20 amount to be rewarded with more ONE.

Learn more about the project here: https://devpost.com/software/cryptopet

Olifant- Crowdfunding

Olifant by Dnah Berberin, is a crowdfunding app for mobile devices.

There are 2 groups of users for Olifant: investors and crowdsourcers.

The shared features for these 2 groups include:

Built-in account management. We can both import the data from an external source and use in-app data.
Browse currently active crowdsourcing projects.

Learn more about the project here: https://devpost.com/software/shofar

Blinkit- Light on Harmony

Blinkit by Techtek, brings Harmony to your devices! Get notified with light and sound when Harmony blockchain action are detected. Supported devices are inexpensive, widely available and it’s opensource.

More devices will be made compatible, and more functions will be added and beside that, Harmony branded USB flash drive prototypes are in development to explore the possibilities with a dedicated branded device, besides this prototype other options, solutions, and devices are explored and considered as well.

Learn more about Blinkit here: https://devpost.com/software/blinkit-ephtol

Pay it Forward — Charitable Funds

Pay It Forward by Ying Qiao allows a user to request tokens from a fund. A request contains a promise to give donations back in the future. The user should redeem a promise with the tokens later.

Learn more about Pay It Forward here: https://devpost.com/software/pay-it-forward-962ag3

Ecopet— Gamified savings Game

Ecopet by Ngo Van Nghia is inspired by kids saving money, the tokens will also be saved and kept by a virtual pet. At first, the dapp only stops saving money on pets, later on these savings can be used to invest in financial investment funds. Users can save their money by adopting, raising pets (through buying food for a pet by ONE).

Play and learn more about the project here: https://devpost.com/software/ecopet-1iorbs

King’s Coin- Indonesian Voucher Data

King’s Coin by Leonardus Litik is inspired by the small shop and street vendors in Indonesia which sell what we called Voucher Data. It is a voucher for digital products like airtime or game item. It is unique, it can be bought but it can not be sold back for money. It still possible to be sold back to money in the black market but the price will drop > 30%. This happens because the voucher provider still dominated by big companies, telco, and they take a big cut to redeem the voucher.

Voucher IDR (VIDR) is a voucher for the digital products in Indonesia. It is an HRC20 token based on stablecoin RUPE in harmony blockchain. It has some additional functions:

Generate a voucher. Anyone can generate/mined voucher as long he has RUPE and ONE for a gas fee. The street vendor and small shop now have another voucher as an alternative.
Redeem voucher. Now any merchant or startup can accept voucher payment easily and redeem it back to stable coin RUPE. The difference in price is very small (3% vs >30%) in RUPE (exclude gas fee).
Sponsored payment. A transaction in the blockchain is complicated for the end-user. Users must have a native coin to pay for gas. Inspired by EIP 865, we make this function that can be called without gas. A user just needs to sign and sent the signature to the merchant. Merchant will pay for gas.

Learn more about Kings Coin here: https://devpost.com/software/king-s-coin

Start Building on Harmony today!

Thank you to all Harmony participants! We look forward to your continued participation in future hackathons!

Developers can build on Harmony today, a fast and open blockchain for decentralized applications. Harmony Mainnet supports state sharding with instant finality. Our staking mechanism reduces centralization while supporting delegation and slashing.

We ❤️ Developers.

Got an idea? Build it on Harmony and Apply for a Grant.