Solidity

What Solidity is

Key facts:

• Statically-typed language with curly-brace syntax.
• Influenced by JavaScript, C++, Python.
• Compiles to EVM bytecode for execution.
• Most-used smart-contract language by far.
• Maintained by Solidity team (originally part of Ethereum Foundation).

Solidity has been the dominant smart-contract language since 2015.

Key features

Several distinctive elements:

• Contract structure — code organized into contracts (similar to classes).
• State variables — persistent storage on-chain.
• Functions — public, external, internal, private visibility.
• Modifiers — reusable function preconditions.
• Events — emit logs that off-chain systems can read.
• Inheritance — multiple inheritance for code reuse.

Each enables specific smart-contract patterns.

Standard libraries

The most-used:

• OpenZeppelin Contracts — battle-tested implementations of common patterns (ERC-20, ERC-721, access control, etc.).
• Standard for production use in most major protocols.
• Audited and maintained.

Most production Solidity uses these libraries rather than reimplementing primitives.

Common pitfalls

Several recurring issues:

• Reentrancy (reentrancy attack).
• Integer overflow (mostly fixed in Solidity 0.8+).
• Access control mistakes.
• Front-running vulnerabilities.
• Gas optimization issues.
• Upgrade-pattern complications.

These have produced many exploits over the years.

Solidity vs. alternatives

Other smart-contract languages:

• Vyper — Python-influenced; emphasizes safety.
• Yul — low-level; used internally by Solidity.
• Huff — assembly-like; performance-critical code.
• Rust — used on Solana and other non-EVM chains.
• Move — used on Sui, Aptos.

Each targets different chains and trade-offs.

What developers should know

For Solidity development:

• Use OpenZeppelin rather than reinventing.
• Follow established patterns for security.
• Get audits before mainnet for serious protocols.
• Stay updated on language version and security best practices.
• Hardhat or Foundry are the standard development frameworks.

What individuals should know

For most users, Solidity is invisible:

• Smart contracts are written in Solidity but you don't see the code.
• Contract source verification lets you read deployed contracts.
• Most major protocols are written in Solidity.

Solidity has become the lingua franca of smart-contract development. Its dominance reflects Ethereum's broader position; alternative languages serve specific niches but Solidity remains primary.