Layer 1
The programmable blockchain behind smart contracts and DeFi.
A proof-of-stake blockchain whose EVM runs smart contracts written in Solidity or Vyper. Home to most DeFi, NFTs and token standards (ERC-20, ERC-721), and the settlement layer for a growing ecosystem of rollups.
EthereumBeginnerEtherscan recompiles your source and compares bytecode. Verify with forge --verify or hardhat verify and a V2 API key; mismatches come from compiler version, optimizer, viaIR, EVM version, constructor args or paths.
#dev-tools#smart-contracts#troubleshooting
EthereumIntermediateMEV is profit from ordering transactions. A sandwich attack front-runs and back-runs a public swap, capped by its slippage. Use tight minimum outputs from fresh quotes and private RPCs.
#defi#mev#security
EthereumIntermediateApprove is safe; unlimited, forgotten allowances and unread permit signatures are not. Approve exact amounts, use permit with short deadlines, read every typed-data signature, and revoke old approvals.
#security#tokens#wallets
EthereumIntermediateStorage dominates gas costs: pack variables, cache storage reads, use constant, immutable, calldata and custom errors, emit events for off-chain data, and measure every change with forge snapshot.
#gas-&-fees#performance#solidity
EthereumBeginnerIt's usually a max fee below the base fee, a low tip, or an earlier stuck nonce. Speed up by resending with the same nonce and higher fees; cancel by sending 0 ETH to yourself with that nonce.
#gas-&-fees#transactions#troubleshooting
EthereumAdvancedA proxy holds storage and delegatecalls an implementation. Transparent proxies keep upgrade logic in the proxy; UUPS puts it in the implementation, which is cheaper but can brick upgrades if done wrong.
#security#smart-contracts#upgrades
EthereumBeginnerChoose Foundry if your team lives in Solidity and wants fast fuzz and invariant tests; choose Hardhat if contracts ship inside a TypeScript stack. Many teams use both with shared compiler settings.
#dev-tools#solidity#testing
EthereumIntermediateUpdate state before any external call (checks-effects-interactions), add nonReentrant to every function sharing that state, and treat token hooks and user-supplied addresses as external calls.
#security#smart-contracts#solidity
EthereumIntermediateThe EVM hit a REVERT and undid the call. The reason is in the revert data: decode Error(string), Panic codes and custom errors with ethers, or replay a failed transaction with cast run.
#smart-contracts#solidity#troubleshooting
EthereumIntermediateNonce too low means that nonce is already used; underpriced means a pending tx holds it and you didn't raise both fee fields enough. Pick nonces from "pending" and serialize sends per key.
#ethers.js#transactions#troubleshooting
EthereumBeginnerRecently, Indian crypto startup Polygon announced that it is acquiring Hermez in a 250 million MATIC deal. A "layer 2" platform on the Ethereum blockchain, Polygon said that Hermez will be absorbed into its ecosystem under the name Polygon Hermez, where it will become a part of the growing Polygon…
#news
