Challenge #0
Tokenization
🎫
Create a unique token to learn the basics of 🏗️ Scaffold-ETH 2. You'll
use 👷♀️ HardHat to compile and deploy smart contracts. Then, you'll
use a template React app full of important Ethereum components and hooks.
Finally, you'll deploy an NFT to a public network to share with
friends! 🚀
Challenge #1
Decentralized Staking App
🦸
A superpower of Ethereum is allowing you, the builder, to create a simple
set of rules that an adversarial group of players can use to work together.
In this challenge, you create a decentralized application where users can
coordinate a group funding effort. The users only have to trust the
code.
Challenge #2
Token Vendor
🤖
Smart contracts are kind of like "always on" vending machines that
anyone can access. Let's make a decentralized, digital currency (an
ERC20 token). Then, let's build an unstoppable vending machine that
will buy and sell the currency. We'll learn about the
"approve" pattern for ERC20s and how contract to contract
interactions work.
Challenge #3
Dice Game
🎰
Randomness is tricky on a public deterministic blockchain. The block hash is
the result proof-of-work (for now) and some builders use this as a weak form
of randomness. In this challenge you will take advantage of a Dice Game
contract by predicting the randomness in order to only roll winning
dice!
Challenge #4
Build a DEX
💵
Build an exchange that swaps ETH to tokens and tokens to ETH. 💰 This is
possible because the smart contract holds reserves of both assets and has a
price function based on the ratio of the reserves. Liquidity providers are
issued a token that represents their share of the reserves and
fees...
Dive into end-to-end dApp development, receive mentorship from BG members, and
learn how to collaborate with fellow developers in open‑source projects.
Challenge #5
🌽 Over-Collateralized Lending
💳
Build your own lending and borrowing platform. Let's write a contract
that takes collateral and lets you borrow other assets against the value of
the collateral. What happens when the collateral changes in value? We will
be able to borrow more if it is higher, or if it is lower, we will also
build a system for liquidating the debt position.
Challenge #6
💰 Stablecoins
Bitcoin ETFs List
Bitcoin is a cryptocurrency created in 2009 by an unknown figure under the alias Satoshi Nakamoto. This cryptocurrency is built on the foundational principles of blockchain, which allows for a recorded unalterable, decentralized ledger of transactions to be maintained on a distributed network with no single point of failure. Bitcoins are created through the "mining" process, which relies on specialized computers to solve math puzzles of ever-increasing complexity. There is a finite supply of just 21 million bitcoins, meaning no more can be mined once that number is reached. Most sources project that the last bitcoin will be mined in 2140. As of the beginning of 2024, some 19 million coins have already been mined.Bitcoin has opened up the doors to pseudonymous transactions and more efficient transfer of capital across borders as well as created a new digital store of value. It has been a disruptive force since its creation, challenging the business models of financial services institutions and central banks alike. However, the bitcoin economy is still very much in its infancy, and its growth potential and inherent risks are very high. Due to its volatility, it's possible to reap extraordinary gains (and, of course, losses) in the short term by trading bitcoin. But there is still quite a bit of uncertainty among regulators over securely trading and holding bitcoin for most investors. Those risks made the Securities and Exchange Commission uneasy when it came to approving an ETF offering direct access to the cryptocurrency, even after other countries offered such products.
Funds that hold futures contracts on bitcoin were approved in the U.S. in October 2021, and investors could also get some access to bitcoin via funds investing in the equities of companies involved in the blockchain and crypto-related businesses. And after roughly a decade of lobbying, the SEC finally approved the first physical bitcoin ETFs in January 2024, with the first 10 funds launching on January 11, 2024, following a successful lawsuit by ETF issuer Grayscale. To limit the list to physical, spot bitcoin ETFs, visit our Top Physical Bitcoin ETFs. Click on the tabs below to see more information on Bitcoin ETFs, including historical performance, dividends, holdings, expense ratios, technical indicators, analysts reports and more. Click on an ETF ticker or name to go to its detail page, for in-depth news, financial data and graphs. By default the list is ordered by descending total market capitalization. As of 10/22/25
Challenge #7
📈 Prediction Markets
Physical (Spot) Bitcoin ETFs
Physical bitcoin ETFs first launched on January 11, 2024.
Although the first filing for such a product was made back in 2013, the SEC had rejected the proposal and all subsequent similar ones on the grounds that bitcoin was unregulated and the risks to investors were too great.
However, it opened the floodgates to spot bitcoin ETFs after Grayscale won a lawsuit against the regulator over the conversion of Grayscale's bitcoin trust into an ETF.
Click on the tabs below to see more information on Physical Bitcoin ETFs, including historical performance, dividends, holdings, expense ratios, technical indicators, analysts reports and more.
Click on an ETF ticker or name to go to its detail page, for in-depth news, financial data and graphs.
By default the list is ordered by descending total market capitalization. As of 10/22/25.
Challenge #8
🔒 ZK Voting
🔒
Build your own decentralized voting system using zero-knowledge proofs.
Let's write a contract that allows users to vote on a topic and the
results will be computed off-chain using zero-knowledge proofs.
Challenge #9
Oracles
🔮
Build three powerful oracle systems bringing real-world data on-chain! Level
up from simple whitelist oracles to staking-based systems, and finally to
optimistic oracles with challenge periods. 🛡️ Learn crucial security
trade-offs while implementing dispute resolution and economic
incentives.
Build Idea
Multisig Wallet
👩👩👧👧 Using a smart
contract as a wallet we can secure assets by requiring multiple accounts to
"vote" on transactions. The contract will keep track of
transactions in an array of structs and owners will confirm or reject each
one. Any transaction with enough confirmations can
"execute".
Build Idea
SVG NFT
🎨
Create a dynamic SVG NFT using a smart contract. Your contract will generate
on-chain SVG images and allow users to mint their unique NFTs. ✨ Customize
your SVG graphics and metadata directly within the smart contract. 🚀 Share
the minting URL once your project is live!
