// blog
In this article you will find 100 questions to prepare your Solidity job interview. Questions are grouped into easy, intermediate and difficult categories. Easy Intermediate Diffic…
There are a few other articles /videos that claim to explain how to get a job as a blockchain developer. However, none of these resources were created by people who actually got a…
In Solidity smart contracts, there are 4 memory locations: storage memory stack calldata They all have different lifetimes and it's not always easy to choose which one is right. In…
TLDR: web3-beta 1.0.0-beta.55 npm install web3@1.0.0-beta.35 If you have worked with web3 before, you might have noticed a few.... glitches to say the least. The most annoying thin…
In Ethereum, there are 2 APIs to interact with a smart contract: Calls (eth_call) Transactions (eth_sendTransactions) In Solidity (the language for writing Ethereum smart contracts…
The documentation of the Truffle framework is pretty good, but it can be a bit overwhelming for a beginner. This cheatsheet is a condensed version giving you the bare minimum you n…
Disclaimer: the price increase will NOT affect existing users who subscribed before June 10th. If you are an existing subscriber or that you subscribed before June 10th, you will l…
Have you ever heard of the 12-factor app ? That's a document created more than 20 years ago that describes the best practices that must be followed in…
When you develop a Dapp, you need the Solidity ABI of your smart contract in order to configure web3 to interact with your contract. This Solidity ABI is a json document produced b…
Todolist Dapp tutorial series updated with Drizzle: Now this series is available with jQuery, then 1st Refactor with React and 2nd refactor with Drizzle Introduction to Drizzle and…
In this Solidity tutorial you are going to learn how to code Solidity smart contracts by developing 5 smart contracts on Ethereum, with step-by-step instructions. This tutorial is…
ERC20 tokens are a key component of many Ethereum Dapps. They usually represent some sort of ownership over a product, service or asset. They largest use case has been for ICOs but…
EatTheBlocks Pro just reached a new milestone: there are now more than 100 videos on Ethereum & Solidity development. That's 16 hours of high quality content. Below are a few selec…
EatTheBlocks Pro has now more than 100+ video ! - 16h of high-quality tutorials for Solidity and Ethereum Solidity v0.5.6 released - bug fixed in optimizer code and progress made o…
In the last episode I gave you an introduction to Drizzle and we built a simple Dapp using Drizzle, Truffle and React. To speed up development, we used a package of pre-built drizz…
In this episode I am going to introduce you Drizzle, a frontend framework for Ethereum Dapps. We will also build a simple Dapp using this framework, Truffle and React. This will co…
Lottery , Fomo3D & Rock Paper Scissors Solidity tutorials - Have you ever dreamed of running your own decentralized casino? Checkout these tutorials! Building a decentralized reddi…
You know Rock paper scissors right? If you don't, that's a simple game where in each round 2 players make one of 3 moves: rock paper scissors Paper beats rock, scissors beat paper…
Have you heard of Fomo3D ? This is a famous lottery Dapp on Ethereum where the last player to invest in a round win the jackpot! By the way, don't freak out if you visit the page o…
This video is a tutorial to build a lottery smart contract in Solidity. The rules are simples. In each round of the lottery, anybody can send Ether to the smart contract. When enou…
In this video, I will teach you how to build a smart contract to organize events.There will be 2 types of users: event organizers customers Event organizers will be able to organiz…
In this video we will create a loan smart contract with Solidity. There will be 2 kind of parties interacting with the smart contract: investors borrowers The investor will send Et…
Dates are a bit weird in Solidity. Solidity does have some keywords for working with dates, like now , or 1 day , but it does not have a native date type. Instead, dates are repres…
In the last video of the smart contract testing series I showed you the basic usage of the Big Number library to deal with integers. But Big Number has many more trick up his sleev…
In Solidity smart contract, you might have to deal with huge numbers, especially when doing financial transfers. Don't forget that we need to specify Ether transfers in Wei, a fund…
In this article, I will walk you through the code of the Etherdelta smart contract: ERC20 token transfers, orders creation, and trades settlement. The smart contract is written in…
Etherdelta smart contract walkthrough - Full explanation of the Solidity smart contract of Etherdelta (decentralized exchange). How the trade process work? off-chain orderbook and…
In Truffle tests, we have a mysterious contract() function: contract('my test', () => { if('it should ...', () => { }); }); It's Truffle replacement of Mocha describe() function, b…
In Truffle, when you write tests, you can use 'artifacts' and 'web3' objects, without defining these names: const MyContract = artifacts.require('MyContract'); //artifacts was neve…
In this video, we will go through the whole process of test-driven-development (TDD) for Solidity smart contracts: writing the tests in Truffle running the failing tests with truff…
Debug smart contract tutorial - First 4 videos of " Debugging Smart Contract " course available for free on Youtube 0x Development course - I am preparing a new course on 0x develo…
In this video, I will show you what is the basic workflow when you test Solidity smart contracts with the Truffle framework. We are going to learn: files / test folder organization…
In this video, I will introduce you Truffle-Contract , a library that is used by Truffle to communicate with smart contracts. When you use test smart contract with Truffle, that's…
Before we are able to understand how tests work in Truffle, we need to first understand what are contract artifacts and contract abstractions in Truffle, and how they are used to m…
Before we can continue in our course on Solidity smart contract testing , we need to install Truffle 5.0, so that we can benefit from all the new fancy features like support for ES…
In this video, I am going to introduce the testing features of the Truffle framework. You will learn: which language are supported for tests the folder organization…
Before you rush into testing your Solidity smart contracts, it's important to understand the difference between unit tests and integration tests. In this video I am going to explai…
Do you write tests for your Solidity smart contracts? Congrats if you do, and if don't it's time to start! If you do, do you write your Solidity smart contract first, and only afte…
We will finally finish our DAO smart contract! So far we can vote for investment proposals, but after the voting time is over we need to actually execute the investment proposal, b…
Beginner-friendly smart contract tutorials - 5 first smart contracts of " smart contract 30 " course uploaded on my youtube channel DAO smart contract tutorial - I finished to uplo…
In this video, we are going to allow investors of the DAO to: create investment proposals vote on each investment proposal We will manipulate Solidity mappings a lot, including nes…
In this video, we are going to allow investors to cash out on their investment, in 2 ways: By redeeming their shares against Ether from the smart contract By selling their shares t…
In this video, we start to build the DAO smart contract, and implement the following features: Collect investor money in Ether Keep track of investor money in shares…
In this new series of videos, we are going to build a DAO (Decentralized Autonomous Organization) smart contract. The DAO was a revolutionary kind of investment fund implemented as…
In this video I will show you some advanced features of the Remix Debugger like: stepping over functions breakpoints These features allow you to quickly find the place of the Solid…
he Remix debugger is a powerful that allows you to debug your Solidity code. Usually, if you are stuck and don't know how to fix a buggy Solidity smart contract, the Remix debugger…
Do you like often use console.log() statement to debug your Javascript code? Convenient, uh? How about Solidity smart contracts, can we do the same? Well, yes and no. In this video…
In Solidity, require and revert statements are used to check some pre-conditions before executing the main part of a function. However, these Solidity constructs can also be used t…
In Solidity, you can return some values from functions, like in other programming languages. Its also possible to use these return statements to inspect some variables and do some…
When I started learning Solidity, there was nothing more frustrating than running accross "VM Exception: invalid opcode" or "VM Exception: revert" errors. These errors messages are…