Ethereum Hackers Built Key Infrastructure Over the Weekend

A look at some of the best ETHWaterloo projects.


Hello defiers! This post will be dedicated to the projects of ETHWaterloo, the Ethereum hackathon that happened over the weekend.

These events consist of getting a bunch of developers to build Ethereum-based applications over the weekend in exchange for prizes –this year sponsors awarded about $100,000. They come from all over the world and hack throughout the day and very late into the night. I’ve even seen a couple of sleeping bags at the venue. The first hackathon was in Waterloo in 2017 and there have been 14 different events –and a crypto boom and bust– since. Two years later, Ethereans are back where it all started for ETHGlobal but arguably also for Ethereum itself, as Vitalik Buterin, the network’s creator, grew up in Toronto and studied computer science at the University of Waterloo.

The 65 projects submitted over the weekend brought total hackathon projects to more than 1,000 –some famous projects to come out of an Ethereum hackathon include CryptoKitties and InstaDApp. This time, there were more than 800 applicants and 300 total hackers, half of them beginners or new to Ethereum. These numbers speak to Ethereum’s biggest strength over competitors; a large and global community of builders.

[Read my post on Ethereum hackathons by the numbers]

It’s worth looking at the projects that come out of these events to see developers’ latest innovations and what may be the next big thing in Ethereum and blockchain. It’s also exciting to see how these teams are building basic infrastructure that’s making Web 3 gradually feel like the internet everyone’s used to. Unlike past events, there wasn’t such a big focus on DeFi, save notable exceptions. It was all about smart wallets, messaging and games.


Hackers hacking at ETHWaterloo


An in all ETHGlobal events, there are five finalists instead of a first place winner. These were:


Sheetcoin is the genius idea of turning Google Sheets into an Ethereum wallet. It allows users to send ERC20 tokens to Gmail addresses. The recipient doesn’t even need to have the wallet installed; all they need is a Google account, which opens up the universe of potential crypto users to 3 billion.

Tokens can then be withdrawn into another wallet, as Sheetcoin is fully connected to Ethereum. So yes, these guys built a Google Sheets sidechain. The transactions use OAuth, which is the standard that’s commonly used to grant websites or applications access to information without revealing passwords.

It’s also pretty funny that Ethereum critics often say that most dapps “should just be a spreadsheet.” and now there’s an actual Ethereum spreadsheet.

Eth P2P VOIP (E.TH.PhoneHome)

This project uses Ethereum to create a system that prevents spam calls, prviders selling your data and SIM swapping. Eth P2P VOIP allows calling an Ethereum address, and places such a high default price on any token that everybody is blocked by default. Users define a list that can call for free and also a price for a token they are willing to accept a call for. If a caller who is not on the list calls, and the user doesn’t answer, the unlisted caller can withdraw the funds they would have otherwise paid.

DeFi Custody Wallet

This is a smart contract wallet that plugs into MetaMask, which means it can be used with any Dapp. It includes a “dead man switch,” which is a mechanism that sends all of the wallet’s digital assets to a pre-determined address (a family member’s address, for example), if the the account isn’t used for a pre-determined period of time, signaling maybe the user lost their private key or died.


This project allows MetaMask users to message each other using their ENS names, which are human-readable names connected to Ethereum addresses. Users can send a message to any address or ENS name, their message will be put on decentralized data storage and sharing protocol IPFS, with the hash uploaded to the smart contract. The recipient is able to access and read the message directly on MetaMask, without having to use an additional Dapp.

Wallet Notify

This is a standardized way of sending push notifications to Ethereum addresses so users can be notified, for example, when their loan is about to get liquidated, when their domain is about to expire, when there’s a governance vote coming up, etc. The team forked MetaMask and created a standard that can work with any wallet.


Hackers hacking at ETHWaterloo

Other Cool Projects

I had the privilege of judging so got to see other projects in detail. These are some of the ones I liked most.


This was one of the best DeFi-focused projects. The idea is to create synthetic tokens using UMA linked to DeFi platforms that don’t have tokens using different metrics that signal traction and health. Their first experiment was a Compound-linked token. This would allow users to speculate on these platforms as if they had shares.


The app estimates the users’ carbon footprint per Ethereum transactions and gives them the option of transferring ETH to a curated list of projects/organizations dedicated to offsetting carbon emissions. Users rewarded with GuiltFree tokens, an ERC20 token which represents 1 tonne of CO2.


This is a fun game that converts the number of times users rotate their phones into points. Points are converted into tokens and therefore, into money.


This app wants to empower women to take control of their health and fertility data, allowing users to represent egg donations with non-fungible tokens.

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About the author: I’m Camila Russo, a financial journalist writing a book on Ethereum with Harper Collins. I was previously at Bloomberg News in New York, Madrid and Buenos Aires covering markets. I’ve extensively covered crypto and finance, and now I’m diving into DeFi, the intersection of the two.