This solution provides a level of security that is enough to automate critical decision making in any DAO such as automatic protocol modification or even autom
How to Solve "Struct Containing a (Nested) Mapping Cannot be Constructed" in Solidity
In level 3 you have to play a game: coin flip. To complete this level you'll need to guess the correct outcome of a coin flip 10 times in a row
In challenge 5 you are given 20 tokens to start with and you will beat the level if you somehow manage to get your hands on any additional tokens.
Overflow is a situation when uint reaches its byte size. Then the next element added will return the first variable element. This is only for <0.8 Solidity.
How to create a BEP-20 token on BSC using Remix.
Today, cryptocurrencies and blockchain have changed a lot of traditional methods and solutions.
Contracts that use the tx.origin to authorize users are vulnerable to phishing attacks.
In general, I’ve found there to be 5 classes of Solidity exploits. Each exploit has a certain “code smell” associated with it.
This tutorial combines blockchain technology, real-time communication, and user-generated content to create an interactive platform that rewards users for their
Reentrancy attack is one of the most destructive attacks in Solidity smart contract. It occurs when a function makes an external call to another
The attacker can create a contract with a selfdestruct() function, send ether to it, call selfdestruct(target) and force ether to be sent to a target.
In this guide, we'll be diving into solidity vulnerabilities and exploiting a solidity constructor.
A list of basic blockchain terms every beginner should know.
how to create a mapping in solidity
Smart Contracts are immutable, transparent, secure, and decentralized. Follow this example to learn how to write them with the programming language solidity.
In this tutorial, you will learn the following; How to set up an Error-free Web3 project, How to code an NFT minting smart contract, How to code the frontend...
In this short tutorial, I would like to show you the basics of events in Solidity.
3/23/2023: Top 5 stories on the Hackernoon homepage!
Non-Fungible Tokens (NFTs) have gained significant popularity in the blockchain space, enabling creators to tokenize and sell unique digital assets.
The demand for Web3.0 solutions is at an all-time high, but there isn't enough material available to usher in the army of developers required to fill the job op
A Merkle tree is a data structure hierarchy used to verify if a particular data is part of a dataset without expending too many resources.
In level 4 of the Ethernaut Game, our goal is to claim ownership of the Telephone contract.
Given the vast potential of blockchain technology, it's no surprise that there is high demand for workers with blockchain engineering skills.
With a $4 billion market cap in 2022, and a daily trade volume of approx $150 million, here's how a non-technical person built the biggest DEX in the world.
How to implement better price feeds in smart contracts
Claim ownership of the contract. Reduce the balance of the contract to 0.
In this article, I modeled how to visualize codes, and also visually told you how developers or hackers read these codes.
Following part one of this tutorial, we will be building the frontend side of this project.
In this tutor, we will set up Hardhat with Typescript. Hardhat is a development environment for compiling, deploying, testing, and debugging Solidity Smart Cont
Including a code sample using the ERC20 token standard.
Smart contracts, in general, offer the ability to determine factors and expectations set out by the contract. In the field of programming, factors and expectations can be described as ‘variables’ and ‘conditions’ within the actual code.
TL;DR
Imagine you are writing a Solidity smart contract and one of its properties can be characterized as a type or state. In other words, something from a limited set of options. You immediately say to yourself: ”Great, I’ll just use enum type for this state variable.” On the one hand, this approach has some benefits like increased readability. On the other hand, it can easily take you down a tricky road potentially leading to problems.
This tutorial will teach you how to build a decentralized blockchain application from the ground up that will interact with a ReactJs frontend.
In this tutorial, you will learn a very crucial smart contract skill for disbursing money (Ethers) to multiple accounts with a click of a button.
The world of work is changing, and more and more businesses are looking for employees with web3 skills. Here is where you can find job openings online.
In this article, I'm going to give you a roadmap and some of the best resources on the internet that will definitely help you get your first job in Web3.
Here I'd like to introduce a website developed by me and my friend in order to provide a better experience for Ethereum smart contracts developers and blockchain enthusiasts - https://justsmartcontracts.dev/. But first I'm going to explain the reasons lead to creating of this website.
First things first, it’s called Vyper, not Viper.
In this tutorial we’ll be walking through building and deploying a decentralized lottery smart contract in Solidity using [Hardhat].
Wondering how to implement Drizzle using React Hooks?
How did we bypass the sweeper bot and saved $26K tokens in the Dark Forest of Blockchain ?
In this article I’ll introduce an implementation for Singly and Doubly Linked Lists, which you can reuse or modify for your own purposes. All the code is available in github or as an npm package.
Put tokenized items for sale in a decentralized classifieds board
An introduction to hacking web3 and smart contracts
Solidity design patterns are essential for creating secure, robust and scalable smart contracts. In this tutorial, we will learn proper implementations
How to code a minimalistic NFT contract on the Ethereum blockchain in Solidity
In this article, we will create a simple full-stack application using React, Hardhat, Solidity, Ethers.js, and Metamask that can be used as a boilerplate.
The Forward Trust design pattern used in the Yield Protocol simplifies integration and makes scaling easier.
Public blockchains enable us to build decentralized web applications (Dapps) that are censorship-resistant and have built-in economic incentives.
Three example configurations for the new OpenZeppelin access control contract.
Re-entrancy attacks in Ethereum smart contrats explained, how to develop, how to avoid them, and how to circumvent them.
A gas efficient alternative to ECDSA and Merkle Trees for airdrops and presales.
Hey everybody, this is the second post of the series on writing apps the Git way, where you just go take a cup of coffee and browse a Git repo to learn something new!
In PART ONE of this tutorial, we coded the smart contract part of this application with Solidity, now it's time we merge it up with ReactJs.
Write, test and deploy an NFT with Foundry and Figment Datahub.
You decide who does what with your smart contracts
Hey dapp developers! Today I am excited because I am posting the step-by-step process that allowed me to deploy my first Ethereum smart contract on the Ropsten testnet.
Including a code sample using the ERC721 standard.
Unleash the power of decentralized finance by building your own DeFi protocol on the Ethereum blockchain using Hardhat.
If you’re a Solidity developer, you’ll be excited to hear that Truffle now supports console logging in Solidity smart contracts.
Find the Length of Any String in Solidity.
Now let’s build the frontend for interacting with it as you can see above. Not much talking, let’s get coding… We’ll begin by installing the rest of the depend
Original Image by ipopba from Getty Images Pro
Ethereum, the world’s first and dominant smart contract platform, has the largest dapp ecosystem with more than a million deployed smart contracts and hundreds of millions of dollars in monthly transactions
Random numbers in Solidity for Ethereum using the Niguez Randomity Engine
Smart contracts, blockchains, crypto wallets, and more
All but the simplest of Ethereum applications are composed of several smart contracts. This is because of a hard limit of 24KB in any deployed contract, and because your sanity will slip away as the complexity of a smart contract grows.
Building great applications takes both decentralized and centralized databases, and so Koinos is being designed to enable developers to integrate a decentralized database into their stack regardless of how much or how little they want to rely on that database.
This article discusses smart contracts, ethereum, blockchain, decentralization, and the state of DeFi.
Smart contracts are a unique class of software explicitly designed to manage ownership of valuable digital assets. While existing programming environments can be used to keep track of the ownership of assets, they are most typically used in scenarios where they are reflecting ownership rather than defining it directly. Smart contracts are unique in that the value they represent is often embodied directly in the state they maintain.
There are a lot of different gambling platforms out there. But there is almost no project that offers a transparent and fair experience. Let's fix that!
Learn how an Ethereum smart contract can pay your kids, employees, or whomever quickly, fairly, and automatically. No more banks, no more headaches.
The Decentralized Flexible Organization is a new concept, that reshapes how we’re building Decentralized Applications, solving some critical points of failure in the today’s Dapp ecosystem like the needs of a Legal Known Entity to Trust, the slowly Smart Contract Developing and the Centralized or Distributed Servers Needs.
In this tutorial, you will learn how to create a profitable and well-designed NFT marketplace with chat functionality.
This is the first article in a series teaching Solidity. We will create a contract for two business partners that don''t trust
Deploying a smart contract to the Ethereum Network is not as complicated as the process may appear. You only need to finish eight steps to get yours online.
Ethereum development, while still very nascent in feel, has come a long way. When I started developing Solidity smart contracts and Ethereum dapps in 2017, Truffle and Web3.js were the industry standard. These are great tools and I have tons of respect for the people that built them. However, anyone who has used them has dealt with bugs and sometimes poor developer experience. There are a few new tools out there that have clearly been inspired by these first sets of tools and made the developer process much better.
In this tutorial, you will learn step-by-step how to implement a decentralized autonomous organization (DAO) with anonymous chat features.
Connecting Your Decentralized Application (Dapp) with a Backend: A Step-by-Step Guide.
We rely on Slither — a static analysis tool from Trail of Bits to maintain the quality of our audits. Considering the ease of use, it’s a good idea to try it!
Getting started with Foundry by developing, testing, deploying, and verifying your smart contracts with Foundry
The Cosmos network is one of the most promising blockchain networks that enable interoperability between different blockchain platforms.
This blog post describes the integer division error in Ethereum smart contracts and how this error can be prevented. Read on to know more…
TLDR: Eternal Storage provides the stable and flexible base needed to build and maintain long-lived decentralized applications.
This blog delves deep into how I created an onchain Loot Royale NFT Collection Dapp - both smart contract and frontend in the most detailed manner possible
Governors approving a change should know which functions are being called, what parameters are being used, and what effects these will have.
This is the second part of my series around Ethernaut Game. In this post, we will deal with Level 2: Fallout.
This blog describes the access control vulnerability in Ethereum smart contracts and the various fixes available. Read on to learn more…
Ethereum is a blockchain with a built-in Turing-complete programming language. It allows anyone to create a decentralised application, by making use of Ethereum smart contracts.
How to Write Upgradable Smart Contracts
If you want to become a smart contract developer on Ethereum, then you need to learn Solidity. Let's look at 10 great sources that can help you on your journey.
Upon completion, you will have gained a deeper understanding of how to programmatically transmit Ethers and will have a working sample for future reference.
Tokens are an incredibly important part of Ethereum and in Web3. Understanding the standards for each type of token can help you understand how it works.
This blog post describes the Remix IDE, its key high-level features and how to write and debug your first Solidity smart contract. Read on to know more…
Multi-Token Standard (ERC1155) was introduced in 2018 by Enjin.
This blog post introduces the smart contract reentrancy attack bug and its impact along with describing fixes for this type of vulnerability. Read on...
This is an in-depth series of Blogs around OpenZeppelin's smart contract security puzzles. The aim of blogs is to provide a detailed explanation regarding various concepts of Solidity and EVM required to solve a Puzzle. It is highly recommended to attempt to solve these puzzles before reading further.
Learn how to build a notes taking app using web3 storage app in 4 simple steps, using nexts, typescript, ipfs, and zk block.
Blockchain is one of the most revolutionary technologies in today’s tech space. It has transformed businesses and is touted as the main component of the fourth industrial revolution. It is the first permanent, decentralized ledger of records that has revolutionized the system of records.
Learn how to implement Flash swap using Uniswap!
Web3, blockchain, NFTs?! It’s all getting a bit year 3000 out there… We’ve pulled this apart to better understand what the future of work looks like for develop
In Part 2, we’ll be using the API3 QRNG to get truly random numbers into our contract.
Mastering how to create, read, update, and delete records from the blockchain is a skill you must understand. Yes, you can delete stuff from the blockchain...
Unlike my sleeping pattern, design patterns are meant to make things more stable and predictable in the future. It is an elegant solution to common problems in software design.
We will create ERC-721 smartcontract, deploy to Goerli with Hardhat + Solidity. For minting we will use NextJs + WalletConnect + Web3Modal
we'll take a look at how to create a smart contract that can be used to conduct a raffle draw on the Ethereum blockchain.
This story is the second part of my ERC series, in this post, you will get a complete understanding of the NFT contracts. Development, working etc.
This blog post describes the integer overflow/underflow vulnerability in Ethereum smart contracts and how it can be fixed. Read on to know more…
You can find partially explained material for ERC token standards, but I have come up with these articles to explain about three major token standards.
Learn how to code crowdsale smart contracts in a solidity programming language. Get to know its properties, processes, and phases for better understanding.
Are you looking to create a cutting-edge platform that leverages the power of web3 to transform the way people book and share accommodations?
How technologies are empowering global citizens to take action for the benefit of humanity
This is an in-depth series of Blogs around OpenZeppelin's smart contract security puzzles. The aim of blogs is to provide a detailed explanation regarding various concepts of Solidity and EVM required to solve a Puzzle. It is highly recommended to attempt to solve these puzzles before reading further.
Now, it's time for you to learn the ultimate trick in building a decentralized voting system.
This article is a tutorial about creating a full-fledged NFT-minting dapp for the Flow Blockchain.
It takes a lot of time and labor to go through each NFT smart contract to retrieve data. Different pre-built NFT APIs can be utilized to address this problem.
This tutorial shows you how to build an NFT auction site using React, Solidity, and CometChat. We will use React for the front end and Solidity for the smart co
In late 2019, the Aragon Project, decided to leave the Polkadot ecosystem due to the lack of a viable blockchain virtual machine at the time. After that, the Polkadot team added EVM support on the Substrate framework, enabling EVM blockchains in the Polkadot ecosystem.
A complete guide to building, running & deploying a DApp with your own Text-to Image script to mint AI-generated art NFTs on FVM Hyperspace Testnet!
So easy, an ape could do it. Thoughts from the lead developer and Top Ape at SnowApe, a Web3 real money gaming project that made a blockchain app from scratch.
As a developer, Ethereum keeps you on your toes. On the plus side, you constantly learn something new and the thrill of the “aha” moments is undeniable.
You’ve likely heard of Ethereum in the context of cryptocurrency, but perhaps not so much in the context of enterprise software.
In general, delays in updating the state of the smart contracts can allow users to "Double-Spend"
To begin with, What exactly are TOKENS ?
I call it the Ethereum Gatling Gun
What you need to know about writing smart contracts on the Tezos blockchain when you come from Ethereum
How do you develop a smart contract for your Dapp? How do you best design the Dapp interface? How do you connect the front end to the backend smart contract?
I asked 10 Web3 Blockchain Developers how they started in Web3, their core skills, the challenges they face and how they can help newbies navigate this path.
Web3 development is officially the new way to build web applications, and if you are not there yet, you need to catch up. The way to master building web3...
Prior to commencing this tutorial, please ensure that you have installed the following RSK workshop pre-requisites on your system:
‘Smart contracts’ is a misnomer. Despite its name, smart contracts on Ethereum are not self-executing digital agreements. Smart contract code only run when triggered by an external account. In other words, you need an external process to trigger the smart contract.
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