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Solidity Guide

From your first Foundry test to DeFi, contract upgrades and cross-chain security. Follow 15 core lessons, then explore 9 focused engineering guides.

15 core lessons9 companion topicsSolidity · Foundry · EVM

Before you start: basic programming experience and a working terminal. The first lesson covers your local toolchain.

Explore the open-source code ↗

01 / Foundations

Your toolchain, the Solidity language and the EVM execution model.

  1. S01

    Foundry Fast-Track: Compiling, Testing, and Scripting Your First Solidity Smart Contract

    Coming soon
  2. S02

    Solidity Value Types, Function Visibility, and Gas-Efficient Custom Errors

    Coming soon
  3. S03

    Mastering EVM Data Locations: Storage, Memory, Calldata, and Mapping Layouts in Solidity

    Coming soon
  4. S04

    Solidity Architecture Essentials: Interfaces, Access Modifiers, and Indexed Event Design

    Coming soon
  5. S05

    Low-Level EVM Calls in Solidity: ETH Transfers, Call vs. Delegatecall, and ABI Selectors

    Coming soon
  6. S06

    Advanced Contract Lifecycle: CREATE2 Deterministic Deployment, Try-Catch, and Post-Cancun Selfdestruct (EIP-6780)

    Coming soon
  7. S07

    Building Secure Contracts from Scratch: Reentrancy Defense in SimpleBank and Voting Systems

    Coming soon

02 / Assets & authorization

Token standards, signatures, distribution and treasury mechanics.

  1. S08

    ERC20 and WETH Deep Dive: 70-Line Raw Implementation vs. OpenZeppelin and 6 Production Traps

    Coming soon
  2. S09

    NFT Asset Modeling in Solidity: ERC721 vs. ERC1155 Raw & OpenZeppelin Implementations

    Coming soon
  3. S10

    Off-Chain Authorization in Solidity: ECDSA Signatures, EIP-712 Typed Data, and ERC20Permit (EIP-2612)

    Coming soon
  4. S11

    Web3 Growth & Batching in Solidity: Cooldown Faucets, Merkle Tree Airdrops, and Atomic MultiCall

    Coming soon
  5. S12

    Treasury & Tokenomics Contracts in Solidity: PaymentSplit, TokenVesting, TokenLocker, and Timelock Governance

    Coming soon

03 / Protocols & production

Vaults, markets, DeFi, upgrades and cross-chain systems.

  1. S13

    Market Mechanisms & Yield Vaults in Solidity: Dutch Auctions, Atomic NFT Swaps, and ERC4626 Vaults

    Coming soon
  2. S14

    Core DeFi Protocols from Scratch: Constant-Product AMM DEX (x⋅y=kx \cdot y = k) and Atomic Flash Loans

    Coming soon
  3. S15

    Production Governance & Cross-Chain in Solidity: Proxy Upgrades (Transparent vs. UUPS), Multisig, VRF, and Bridges

    Coming soon

Companion engineering guides

Troubleshooting, security boundaries and architecture decisions. Read these alongside the core path.

  1. T01

    The Solidity & Foundry Troubleshooting Guide: Fixing 25 Common Build, Test, ABI, and Proxy Errors

    Coming soon
  2. T02

    Raw Solidity vs. OpenZeppelin v5: Code Size, Gas, and Security Trade-offs Across 15 Protocols

    Coming soon
  3. T03

    Why Naive ERC20 Integrations Lose Funds: Non-Bool Returns, Fee-on-Transfer, and Approval Race Conditions

    Coming soon
  4. T04

    Upgradeable Smart Contract Pitfalls: Preventing Storage Collisions, UUPS Locks, and Uninitialized Proxies

    Coming soon
  5. T05

    6 Hidden Vulnerabilities in EIP-712 and ecrecover: Zero-Address Bypass, Cross-Chain Replay, and Malleability

    Coming soon
  6. T06

    Defending Against First-Depositor Inflation and Donation Attacks in ERC4626 Vaults and AMM Pools

    Coming soon
  7. T07

    Why Cross-Chain Bridges Get Drained: Relayer Compromise, Uncapped Minting, and Rate-Limited Defenses

    Coming soon
  8. T08

    The Practical Foundry Testing Cheat Sheet: Mastering vm.prank, expectRevert, vm.sign, and Time Manipulation

    Coming soon
  9. T09

    From 50-Line Tutorial Contract to Production Web3 System: 8 Engineering Layers Missing from Demos

    Coming soon