Using the new Uniswap v2 as oracle in your contracts
How does the Uniswap v2 oracle function and how to integrate with it
We've covered Uniswap previously here . But let's go through the basics first again. What is UniSwap? If you're not familiar with Uniswap yet, it's a fully decentralized protocol for automated liquidity provision on Ethereum. An easier-to-understand description would be that it's a decentralized...
Smock: The powerful mocking tool for Hardhat
Features of smock and how to use them with examples
We’ve covered mocking contracts before , but now there’s an additional great tool available: smock . It simplifies the mocking process greatly and also gives you more testing power. You’ll be able to change the return values for functions as well as changing internal contract storage directly!...
How to build and use ERC-721 tokens in 2021
An intro for devs to the uniquely identifying token standard and its future
The ERC-721 standard has been around for a while now. Originally made popular by blockchain games, it's more and more used for other applications like Defi. But what exactly is it? A non-fungible token (NFT) is a uniquely identifying token. The word non-fungible implies you cannot just replace...
Trustless token management with Set Protocol
How to integrate token sets in your contracts
With Set Protocol you can create baskets of tokens that give users different levels of exposure to underlying assets (currently only ERC-20 tokens). Set Protocol and their TokenSet functionality is the perfect example for making use of the new paradigm of Defi and composability. You can let...
Exploring the new Solidity 0.8 Release
And how to upgrade your contracts to Solidity 0.8
We are getting closer to that Solidity 1.0 release (unless of course after 0.9 comes 0.10). Now Solidity 0.8 has been released only 5 months after the 0.7 release ! Let's explore how you can migrate your contracts today... New features & how to use them Let's look at the two big new features...
How to build and use ERC-1155 tokens
An intro to the new standard for having many tokens in one
ERC-1155 allows you to send multiple different token classes in one transactions. You can imagine it as transferring Chinese Yuan and US Dollars in a single transfer. ERC-1155 is most commonly known for being used in games, but there are many more use cases for it. First of all though, what are...
Leveraging the power of Bitcoins with RSK
Learn how RSK works and how to deploy your smart contracts to it
I'm always interested in what other ways one can use their blockchain and Solidity skills. While many projects are still only in the planning or in testnet status, with Rootstock (RSK) you can transfer mainnet Bitcoins to an EVM sidechain and vice-versa already today. Utilizing the power of the...
Solidity Fast Track: Learn Solidity Fast
'Learn X in Y minutes' this time with X = Solidity 0.7 and Y = 20
You might be familiar with the Learn X in Y minutes. For example you could learn JavaScript in 20 minutes at https://learnxinyminutes.com/docs/javascript/ . Unfortunately there is no equivalent for Solidity, but this is about to change. Do you have 20 minutes to learn all of the basics? We even...
The future of a Decentralized Etherscan
Learn how to use the new Sourcify infrastructure today
We all love Etherscan . It's a great tool to interact with contracts, read the source codes or just see the status of your transactions. But unfortunately as great as it is, we should not forget that it's a centralized service. The website could be taken down any day. This kind of defeats the...
Integrating the 0x API into your contracts
How to automatically get the best prices via 0x
How can you add 0x to your contracts to automatically convert between tokens? We have done this in a similar fashion before with Uniswap and Balancer . The 0x API has a bit of a twist. Let's take a look why... Why you want 0x in your contracts? It's simple: Okay, but seriously. Let's see why the...
How to build and use ERC-777 tokens
An intro to the new upgraded standard for ERC-20 tokens
The new upgraded standard for ERC-20 tokens is becoming more and more popular. It's fully backwards compatible, you can easily create one using the Openzeppelin contracts and there are many interesting new features not available in ERC-20. Should you upgrade from ERC-20? Well let's look into what...
COMP Governance Explained
How Compound's Decentralized Governance is working under the hood
You might have heard about the COMP token launch. With a current market cap of over 350 million USD, the token has accumulated massive value. But what is the actual utility of COMP? It's a governance token. Compound being a fully decentralized system (or at least on the way towards it), has a...
How to prevent stuck tokens in contracts
And other use cases for the popular EIP-165
Do you remember the beginning of the Dark Forest story? If not, let's look at it again: Somebody sent tokens to a smart contract that was not intended to receive tokens. This perfectly illustrates one of the issues not only with ERC-20 tokens, but generally with smart contracts. How can we find...
Understanding the World of Automated Smart Contract Analyzers
What are the best tools today and how can you use them?
As we all know, it's very difficult writing a complex, yet fully secure smart contract. Without the proper methods, chances are you will have many security issues. Automated security testing tools already exist and can be a great help. One of the main challenges for these tools is to maximize...