Compilation

Relaycode compiles Solidity contracts server-side using industry-standard compilers.

Compilation Targets

EVM Mode

Uses solc (the standard Solidity compiler) to produce EVM bytecode.

• Solidity version: 0.8.34
• Optimizer: Enabled with 200 runs
• Output: Standard EVM bytecode compatible with all Ethereum tooling
• Use case: Standard Solidity contracts, maximum compatibility

PVM Mode

Uses resolc (Parity's Revive compiler) to produce PolkaVM bytecode.

• Solidity version: 0.8.x (determined by resolc's bundled solc)
• Optimizer: Mode z (size-optimized) with 200 runs
• Output: RISC-V bytecode for PolkaVM
• Use case: Polkadot-native execution, access to PVM-specific features

Import Resolution

Contracts with npm package imports are resolved automatically:

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

The compiler resolves imports iteratively:

1. Attempts compilation with the user's source
2. Detects missing imports from compiler errors
3. Fetches sources from the unpkg CDN
4. Re-compiles with all resolved sources
5. Repeats until all transitive imports are resolved

Supported Packages

Any npm-published Solidity package works, including:

• OpenZeppelin Contracts
• Chainlink
• Uniswap core/periphery
• Solmate, Solady, etc.

Version Pinning

Bare imports (without a version) resolve to the current npm-published version at compile time. For deterministic builds, use versioned imports:

import "@openzeppelin/contracts@5.0.0/token/ERC20/ERC20.sol";

Or compile externally with locked dependencies and use Upload mode.

Limits

Unsupported Features

• Local file imports (./MyLib.sol) — only npm packages and relative paths within packages are resolved
• Solidity versions below 0.8.0 — both compilers target 0.8.x
• Non-Solidity languages — Vyper, Yul, etc. are not supported
• PVM-specific opcodes — selfdestruct, extcodecopy, pc cause compile-time errors in PVM mode

Multi-Contract Files

If your source file contains multiple contracts, a dropdown selector appears after compilation. Select which contract to deploy — its bytecode and ABI are used for the extrinsic parameters.