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smartcontractkit/full-blockchain-solidity-course-js

13,991Audience · developerComplexity · 3/5Setup · moderate

TLDR

A free 32-hour video course that teaches blockchain development from scratch, covering how to write smart contracts in Solidity and connect them to JavaScript web apps using Hardhat and Chainlink.

Mindmap

mindmap
  root((Blockchain Course))
    Topics
      Blockchain basics
      Solidity contracts
      JavaScript frontend
      Security auditing
    Tools
      Hardhat
      Chainlink
      Sepolia testnet
    Skill Level
      Complete beginners
    Outcomes
      Token creation
      DeFi contracts
      Web3 frontends
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Code map

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Things people build with this

USE CASE 1

Work through numbered lessons to write and deploy your first smart contract to the Ethereum Sepolia test network.

USE CASE 2

Build a crowdfunding contract that accepts cryptocurrency and connects to a JavaScript front end.

USE CASE 3

Create your own ERC20 token and a lottery-style contract using Solidity and Hardhat.

USE CASE 4

Learn decentralized governance structures and basic smart contract security auditing.

Tech stack

JavaScriptTypeScriptSolidityHardhatChainlink

Getting it running

Difficulty · moderate Time to first run · 1h+

Course tooling (Hardhat) has changed since recording, expect version mismatches that require debugging before code runs as shown in the video.

Code is for educational use only and has not been audited for production security.

In plain English

This repository holds the code and resources for a video course on blockchain development using JavaScript, originally published on FreeCodeCamp. The course covers how blockchains work, how to write smart contracts in a programming language called Solidity, and how to build web applications that interact with those contracts. The companion video runs over 32 hours and targets complete beginners who want to go from no blockchain knowledge to building real decentralized applications. A notice at the top of the repository flags that this version is no longer actively maintained. The underlying tooling it relies on, called Hardhat, has changed since the video was recorded, which means parts of the written code no longer match what the video shows. You can still follow along, but you will likely need to debug version and dependency mismatches along the way. The authors point newer learners toward a separate training platform called Cyfrin Updraft, though that platform uses a different toolset called Foundry. The course is organized into numbered lessons. Early lessons cover the basics: what a blockchain is, how transactions get recorded, and what gas fees mean. Later lessons walk through writing your first contracts in a browser-based editor, deploying them to a test network, building a funding contract that accepts cryptocurrency, creating your own tokens, running lottery-style contracts, and connecting a front-end website to the blockchain. More advanced lessons cover decentralized governance structures and security auditing. Every code sample comes in both JavaScript and TypeScript versions. The repository references several tools and services used throughout the course: Hardhat for testing and deploying contracts locally, Chainlink for pulling real-world price data into contracts, and the Sepolia test network for practice deployments without using real money. Links to faucets, services that give out free test currency, are included so learners can run transactions immediately. All code in this repository is for educational use only and has not been formally reviewed for production security. The full README is longer than what was shown.

Copy-paste prompts

Prompt 1
I'm following the full-blockchain-solidity-course-js and getting dependency errors with Hardhat. List the exact npm package versions that match the course and explain how to fix version mismatches.
Prompt 2
Using the FundMe contract from this Solidity course, show me how to write a Hardhat test that verifies the owner can withdraw all funds.
Prompt 3
Walk me through deploying the SimpleStorage contract from this course to the Sepolia test network using Hardhat, including getting test ETH from a faucet.
Prompt 4
Explain how Chainlink price feeds work in the context of the FundMe contract from this course, and show the Solidity code that reads the ETH/USD price.
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