Speedrun Ethereum

hey @bankrbot launch $Speedethereum on robinhood chain Use is picture

Wanted to know how prediction markets like @polymarket work... 🤔 So I went to @Speedethereum, and I'm halfway of getting all the fundamentals now 👏 Tysm for the great learning content as always @buidlguidl 🫶

@cryptomastery_ @ETHGlobal @buidlguidl @ethereum @ScaffoldETH @ampersend_ai @1clawAI Nice

Did you catch my talk at @ETHGlobal New York? I covered a BUNCH of topics including... > BuidlGuidl @buidlguidl > SpeedRunEthereum @Speedethereum > ETHSkills @ethereum > Scaffold-ETH @ScaffoldETH > x402 and ampersend @ampersend_ai > 1Claw AI @1clawAI and more... Catch the replay! Link in the comments... 👇

@cryptomastery_ @ETHGlobal @buidlguidl @Speedethereum @ethereum @ScaffoldETH @ampersend_ai @1clawAI 👏👏

10 Challenge Spotlights, one for every challenge on Speedrun Ethereum. Tokenization. Crowdfunding. Token Vendor. Dice Game. DEX. Oracles. Lending. Stablecoins. Prediction Markets. ZK Voting. That's a full cycle. Which one was your favorite?

🧵 How to Safely Call Other Contracts in Solidity Smart contracts rarely live alone. Most real-world dApps rely on contract-to-contract communication. But every call is a potential risk. Here’s how to do it securely 👇

6/ 🧪 Secure Vendor Example A real-world pattern: - Buyer approves ERC20 token - Vendor pulls with transferFrom() - Sends reward token - Uses nonReentrant for safety - Follows CEI

5/ 🔁 Reentrancy is Real Attackers can re-enter your contract mid-function and drain funds. 💡 Defend with: - Checks-Effects-Interactions pattern - OpenZeppelin ReentrancyGuard

Foundry support just shipped on Speedrun Ethereum 🔨 Pick your stack when you start a challenge: Hardhat or Foundry. Try it on the first challenge: npx create-eth@2.0.12 -e challenge-tokenization challenge-tokenization Available for challenges 0 to 4. More coming soon.

Challenge 5: Oracles. The exercise: • Your contract needs off-chain data (a price, a weather feed, a score) • Solidity can only see on-chain state • An oracle bridges the gap, and becomes a trust anchor you have to reason about

Two ways to declare a value that never changes: • `constant` — inlined at compile time. Value has to be known before deploy. • `immutable` — set once in the constructor. Stored in bytecode, not a storage slot. Reading either costs ~3 gas. Reading a storage variable costs ~100 (warm) or ~2100 (cold). Use one of these whenever you can.

Challenge 4: Build a DEX. The exercise: • Constant-product AMM from scratch (`x * y = k`) • Provide liquidity, earn swap fees • Swap against your own pool • Under 50 lines of Solidity at the core