Solidity

Solidity is the primary language for the Ethereum Virtual Machine (EVM). v0.8.28 (2025) focuses on transient storage (tstore) and gas optimization via IR.

When to Use

• Ethereum/L2s: Developing for Optimism, Arbitrum, Base.
• DeFi: Writing logic for tokens, AMMs, and lending.
• NFTs: ERC-721 and ERC-1155 contracts.

Core Concepts

Gas

Every operation costs ETH. Optimization is critical.

Modifiers

Reusable checks. modifier onlyOwner { ... }.

Events

Logging on the blockchain. emit Transfer(from, to, value).

Best Practices (2025)

Do:

• Use Foundry: The 2025 standard for testing (Solidity-based tests).
• Use Custom Errors: error InsufficientBalance(); is cheaper than string requires.
• Use OpenZeppelin: Don't roll your own crypto/auth logic.

Don't:

• Don't ignore reentrancy: Use ReentrancyGuard or Checks-Effects-Interactions pattern.

References

• Solidity Documentation