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Ownable Contracts | Solidity Tips & Examples
Ownable contracts in Solidity are used to implement access control for certain functions. The idea is that only the contract owner, who is typically the deployer of the contract, can execute these protected functions. To do this we will first import the OpenZeppelin library Inside our contract we can then add the onlyOwner modifier to…
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Payable Transfers | Solidity Tips & Examples
Payable transfers are one of a number of ways to send ether from a Solidity smart contract to an external address. In this next example we create a fallback function so that any user can send this contract ether and it will get split between the different addresses. Full code at: https://github.com/jamesbachini/Solidity-Snippets/blob/main/contracts/PaymentDivider.sol Payable fails if…
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Solidity Interface | Solidity Tips & Examples
A Solidity interface is code that provides a set of function declarations without any implementation details. Interfaces are used to interact with 3rd party contracts or external systems by defining a common set of functions that both parties agree to implement. Interfaces are used to define a contract’s external-facing functions, which is the only part…
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OpenZeppelin Libraries | Solidity Tips & Examples
OpenZeppelin libraries are popular for building secure smart contracts on top of pre-audited code in Solidity. The framework includes a number of reusable smart contract components, such as token contracts, access control contracts, and math libraries. In this article we will explore the various Libraries available within the OpenZeppelin framework to give you a tool…
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Arrays in Solidity | Solidity Tips & Examples
Arrays are a fundamental data structure in programming, and Solidity is no exception. In Solidity, there are several types of arrays available, including dynamic arrays, fixed-size arrays, and multi-dimensional arrays. Dynamic Arrays Dynamic arrays are the most common type of array in Solidity. These are arrays whose length can be changed during runtime. To declare…
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Get Contract Balance | Solidity Tips & Examples
To get the contract balance in solidity there are a few different methods depending on if you want the Ether balance or an ERC20 token balance. Contract Balance Eth You can use the address type’s balance property to get the balance of any address, including the contract’s own address. The this value is used to…
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Mapping in Solidity | Solidity Tips & Examples
This article explores how mapping in Solidity is used to for storing key->value pairs, where the keys are of a specific data type and the values can be of any data type. Mappings are declared using the mapping keyword, followed by the key data type in parentheses and the value data type after the parentheses.…
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Variables in Solidity | Solidity Tips & Examples
Variables in Solidity can be classified into several categories based on their data types and scope. In this article we will explore all the different uses of variables in Solidity and look at some example code. Variables in Solidity Solidity variables are used to store and manipulate data in our smart contracts. They come in…
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ERC721 vs ERC1155 | Solidity Tips & Examples
Today we will discuss the differences between ERC721 vs ERC1155 smart contracts and the use cases where each is best suited. These are the two most popular types of smart contracts used for the creation of NFTs (non-fungible tokens). James On YouTube Watch On YouTube: https://youtu.be/B64VBGt3tMU |Subscribe ERC721 Smart Contract ERC721 is the original standard…
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ERC20 Carbon Credits | Creating A Depleting Token
Carbon credits are used to tokenise finances put towards carbon offsetting. On-chain products often have a purchase and burn mechanism where a user must first purchase the token on a DEX and then manually execute a transaction to burn the token. I had the idea to create a automatically depleting token which you just hold…
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zkEVM | Are Zero-Knowledge Rollups The Future Of Ethereum Or A Ticking Time Bomb?
zkEVM is a zero knowledge Ethereum virtual machine, credited as being “the ultimate solution to Ethereum scaling” The Ethereum ecosystem continues to grow alongside concerns around its scalability and privacy. A new technology currently being rolled out aims to address these issues through the implementation of zero-knowledge rollups. In this article, we’ll take a closer…
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ETHDenver | Thoughts & Takeaways From The Biggest US Blockchain Conference
This article is aimed at providing an overview summary of what was talked about at ETHDenver and some of the things I picked up while being there. Buzz Word Bingo I took the schedule and ran through how many talks there were on each of these subjects. Buzz Word No. Of Talks Zero Knowledge 18…
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The Feynman Technique 2.0
The Feynman Technique is a learning tool developed by the infamous physicist Richard Feynman. It involves breaking down complex concepts into simple terms and explaining them as if you were teaching the subject. In March 2020 Covid lockdowns were imposed and I started creating content based on what I was learning or interested about at…
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Anonymous Developer Tutorial | How & Why You Should Code Anonymously
There are plenty of articles and content about why you should be an anonymous developer for blockchain projects but I haven’t seen much content about best practices and how to actually set up an anonymous development environment. In this article we will cover the following:- Anonymous Developer Video Tutorial James On YouTube Watch On YouTube:…
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How To Stake Ethereum | Earn More Yield With Ethereum Staking
Staking Ethereum has become a popular way for crypto investors to earn passive returns on their holdings. Liquid staking tokens like stETH make this process easily accessible. You can buy staking tokens and effortlessly enjoy the rewards of staking Ethereum without having to manage the technicalities of running a node. Lido Finance were first to…
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Advanced MidJourney Prompt Engineering | Unleash Your Inner Artist
As the leading AI image generator, MidJourney consistently produces stunning, high-quality images that range from the bizarre to the breathtaking. As someone who lacks artistic talent, I’ve taken the time to study and master this tool, and in this post I share my insights and tips for getting the most out of it. Follow my…
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Advanced ChatGPT Prompt Engineering
By now you have probably experimented with ChatGPT and realised the huge potential this “calculator for words” has. In this article I share the results of my research on how to make the most of this powerful tool. Whether you’re using ChatGPT as a personal assistant or in a professional setting, you’ll find some valuable…
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Crypto Market Thesis 2023
Once viewed as a fringe market for tech-savvy libertarians, the crypto market has grown exponentially in recent years and is now being recognized as a legitimate asset class by mainstream investors. As we move into 2023, the crypto market is at a crucial juncture, with the potential to continue its explosive growth or face regulatory…
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Remixd Tutorial | How To Take The Solidity IDE To The Next Level
I’ve gone full circle from Remix > Hardhat > Foundry > Remix I find that I enjoy coding most when I’m experimenting with ideas and proof of concepts within the Remix IDE at https://remix.ethereum.org However for more serious projects I inevitably find myself moving out of creative mode and into testing mode in either Hardhat…
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The Psychology Of Money | Book Summary
The Psychology of Money by Morgan Housel covers personal finance from the perspective of a middle aged American value investor. It offers some interesting insights into long-term investing mindsets and the psychology of why we make investment decisions. Evolution of Personal Finance Western economies have seen a transition in the way we work from manual…
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Mean Finance | How To DCA With DeFi
Mean Finance is a DeFi protocol that enables users to dollar cost average (DCA) into a position for an ERC-20 token. In this article we will look at why dollar cost averaging is useful and how Mean Finance works. Why Dollar Cost Average Dollar cost averaging is an investment strategy that simply breaks a entry…
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LayerZero Example | How To Send Cross-Chain Messages In Solidity
In this article we are going to look at how to send messages or data from one chain to another. In this LayerZero example we will be sending a string from Ethereum’s Goerli Testnet to Optimisms Layer 2 Goerli Testnet. Cross-Chain Tutorial Video James On YouTube Watch On YouTube: https://youtu.be/rKVhQHmljXM |Subscribe How LayerZero Works LayerZero…
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How To Debug Solidity Smart Contracts
If you’ve ever received a “gas message” error which makes no sense in Solidity then you’ve probably come across one of it’s greatest flaws. Error reporting and debugging isn’t great for blockchain developers but in this tutorial I’m going to provide some tips, tools and resources to debug Solidity smart contracts. James On YouTube Watch…
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RAILGUN 2.0 | ZK Privacy Protocol
Railgun just announced the launch of version 2.0 this week and in this article we are going to explore the zero knowledge wallet and discuss why privacy protocols are important. In August 2022 Alexey Pertsev was arrested and he has been imprisoned without trial ever since. He was a developer on a ZK mixer called…
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Timeframe & Budgets For Web3 Development
In this article I’m going to provide a timeframe, gantt chart and budget costs for web3 development projects. This assumes a medium sized project for something like a new, innovative DeFi protocol consisting of 5-10 interconnected smart contracts and around 1000 lines of code plus an external audit and dApp frontend. If you are just…
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Dynamic Evolving NFTs | How To Create Dynamic NFTs & dApps
Dynamic NFTs include logic that evolves the underlying data that the NFT contract holds. In this example we will build a picture profile NFT that is upgradeable to an alien 👽 All the source code for this project is available at: https://github.com/jamesbachini/WomenWhoCode Dynamic NFT Smart Contract The Solidity smart contracts will comprise of two tokens:…
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FTX Collapse Explained | The Story Of Scam Bankrun Fraud
In November 2022 the world’s second largest cryptocurrency exchange FTX collapsed, stopped withdrawals and filed for bankruptcy. The stories of the last week are so far-fetched they deserve a Netflix documentary. Here we will look at how FTX was able to defraud the crypto industry of somewhere in the region of $10 Billion US dollars.…
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POAP vs NFT | A Guide With Examples
In this article we will look at what POAPs are and how their technology is built on top of NFT standards. We will also look at how to create simple POAPs and NFTs. In the conclusion I’ve put together some thoughts on why I think POAPs should only be used for fun and not for…
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SAFT Template | Simple Agreement Future Tokens
Below I’ve shared an example SAFT legal agreement and a smart contract which can be used to lock up tokens. James On YouTube Watch On YouTube: https://youtu.be/hpsegda6gvo |Subscribe What Is A SAFT? A SAFT is a simple agreement for future tokens. It is used primarily for blockchain projects to sell tokens at an early stage…
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Ethereum DevCon Bogotá Write Up
In this post I’m going to try to summarise some of the most interesting talks at from DevCon 2022. Here’s a video summary about the key takeaways from the conference. James On YouTube Watch On YouTube: https://youtu.be/kgiAV7z1fwo |Subscribe The main topics for this years event were: One of the best things about the event is…
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Complete Introduction To Web3 Tutorial | Fullstack Web3 Development Tutorial
This video course provides a complete introduction to Web3 development. The Web3 tutorial starts with a simple Hello World smart contract and React frontend before diving in to create something useful on Ethereum mainnet. Introduction To Web3 Development James On YouTube Watch On YouTube: https://youtu.be/RwuG9HluFQY |Subscribe Hello World Smart Contract James On YouTube Watch On…
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Yield Futures With Resonate Finance
Resonate Finance is building a protocol for the creation and sale of yield futures. In this article we will look at what yield futures are, how they can benefit a projects tokenomics & why investors might find them attractive. This post isn’t sponsored and I currently have no stake in Resonate Finance or Revest at…
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Solidity Token Factory Contract Walkthrough
A token factory contract is used to deploy tokens from a parent contract within Solidity. In this simple example we will be deploying an ERC20 token from our factory contract. James On YouTube Watch On YouTube: https://youtu.be/MY9SoGPGVoo |Subscribe Full source code below and on Github: https://github.com/jamesbachini/Token-Factory-Tutorial We start with a standard ERC20 token using the…
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Trading The Merge
Once or twice a year the crypto markets align to provide exceptional trading volumes and volatility. I believe the Ethereum merge will presents one such opportunity for low time frame system trading. James On YouTube Watch On YouTube: https://youtu.be/3ltpF4UGir4 |Subscribe About The Ethereum Merge The merge is happening in just a few days. This is…
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The State Of CBDC Central Bank Digital Currency
Nation states across the world are exploring CBDC’s (central bank digital currency). Many governments including France, Canada, Saudi Arabia & China have pilot schemes already in place. The US dollar is the global reserve currency, it’s used throughout the world as a base asset and more recently as a political weapon in the form of…
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Aligning Founders, VC’s and Stakeholders Interests In A Smart Contract
The blockchain sector prides itself on openness and transparency. Except that is when it comes to early stage VC deals and token allocations. In this article we are going to look at an experimental solidity smart contract which lays out terms, vesting schedules and milestone bonuses on-chain. Team Allocations and VC Unlock Schedules This is…
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Twitter Crypto Ads | Blockchain Advertising Is Live On Twitter
Twitter crypto ads are live after the platform unofficially relaxed its ban on advertising crypto products. Perhaps due to the Elon bid there seem to be more ads showing up and less stringent controls on ad quality. This opens up an opportunity for companies in the sector to use the platform for growth. In this…
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Dune Analytics Tutorial | How To Create A Dune Analytics Dashboard
In this Dune Analytics Tutorial we will look at how the platform works and get up to speed with creating our own queries, visualisations and dashboards to analyse and present blockchain data. Queries, Visualisations & Dashboards Dune Analytics dashboards are built using a 3 step process. First we make SQL queries to pull data into…
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Ownable vs Permissionless Smart Contracts
One of the beautiful things about smart contracts is they can be permissionless where the developers relinquish control to the community and all users are treated equally. However less than 20% of the top 50 protocols by TVL on Ethereum are using fully permissionless contracts. In this article we will look at why this is,…
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Solidity Tutorial | Fixed Rate Staking Contract
In this tutorial we will create a fixed rate staking contract that pays out 1 token for every 1 token staked per year. The contract will be built on an OpenZeppelin ERC20 token library with additional functionality for staking. The user will stake their tokens which will lock them in the smart contract at what…
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Zero Knowledge Proof | How ZKP Works In Blockchain Applications
Zero knowledge proofs offer a method for developers to prove data validity or knowledge of data without revealing the data or additional information about the prover. Zero knowledge proofs are becoming widely used in blockchain applications from smart contracts like Tornado Cash to ZKrollups which are layer 2 blockchains on top of Ethereum. In this…
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3 Examples Of How To Use Assembly In Solidity
Ethereum developers can directly use assembly in Solidity to improve the performance of their code. When OpenSea released the Seaport upgrade it reported the use of assembly reduced gas fees by 35% saving it’s users an estimated $460m per year. Today we are going to go through some simple examples of how and when to…
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Solidity for Beginners
Solidity is the programming language used to develop smart contracts on Ethereum and other compatible blockchains. In this “Solidity for Beginners” tutorial I will take you from setting up solidity tools to deploying your first contract. James On YouTube Watch On YouTube: https://youtu.be/yM6oRMdMiTM |Subscribe Tools & Setup We will be starting in Remix which is…
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GameFi 2.0 | Sustainable Tokenomics & Business Models
GameFi utilises digital assets such as cryptocurrency tokens and NFT’s to create internal economies within games. In this article I look at how tokenomics can be designed to create sustainable business models for gamers, investors and developers. James On YouTube Watch On YouTube: https://youtu.be/Ul_Mza9IyYE |Subscribe GameFi 1.0 Play2Earn Growing up I played computer games on…
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Bear Markets | How Human Psychology Works Against Us
Is loss aversion causing long-term underperformance in our portfolios? In bear markets I find it harder to rebalance my portfolio and allocate capital to riskier investments. This creates an unintentional de-risking in bear markets where there is a better long-term risk to reward. James On YouTube Watch On YouTube: https://youtu.be/6F1Cpk14stE |Subscribe Not a financial advisor,…
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SBTs 👻 | Soulbound Token Solidity Example
Soulbound tokens are non-transferable digital assets. The core concept is storing on-chain data directly relating to a specific address. This is nothing new but there is potential for a ERC SBT contract to provide a industry standard for how we manage user data. James On YouTube Watch On YouTube: https://youtu.be/yCHeHI8hUY8 |Subscribe Ethereum gas costs make…
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Solidity Interface Examples | How To Connect The Lego Bricks Of DeFi
Solidity interfaces allow developers to call external contracts from within their own smart contract. This enables us to build on top of the existing DeFi ecosystem. In this tutorial we will be looking at how solidity interfaces work and going through some example code for common tasks. James On YouTube Watch On YouTube: https://youtu.be/GWZmklp7RTg |Subscribe…
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Hardhat Plugins & Hacks For Solidity Developers
Hardhat provides a lot of features out of the box but with the addition of some 3rd party plugins and some additional code snippets we can add custom functionality to streamline our testing and migration processes. Top 3 Hardhat Plugins These plugins add a lot of functionality to make your life as a developer easier…
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Blood in the streets for crypto markets
A year ago I outlined my 60/40 digital asset portfolio which was 60% crypto and 40% USD stablecoins. One of the biggest benefits to this portfolio is that during market downturns it leaves you with capital to deploy. Today has been one of the most chaotic days in crypto markets ever and I’m going to…
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Foundry Tutorial | How To Debug & Deploy Solidity Smart Contracts
Foundry is a Solidity Framework for building, testing, fuzzing, debugging and deploying Solidity smart contracts. In this Foundry tutorial we will cover the following: Introduction To Foundry [Video] James On YouTube Watch On YouTube: https://youtu.be/VhaP9kYvlOA |Subscribe Smart contracts are most often written in Solidity but tested and deployed using Javascript frameworks such as Truffle or…
