Foundry Cast

Foundry cast

CLI Swiss Army knife for Ethereum and EVM chains.

When to use cast

Use cast when you need to:

• perform read-only calls against contracts
• inspect balances, storage slots, code, receipts, or block data
• encode or decode ABI data quickly from the shell
• send a controlled transaction in an authorized lab

Quick Start

# Balance lookup
cast balance 0x0000000000000000000000000000000000000000 --rpc-url https://rpc.example

# Read-only contract call
cast call 0xContract "owner()(address)" --rpc-url https://rpc.example

# Inspect storage slot 0
cast storage 0xContract 0 --rpc-url https://rpc.example

High-Value Workflows

ABI helpers

cast calldata "transfer(address,uint256)" 0x1111111111111111111111111111111111111111 1000000000000000000
cast abi-decode "(uint256,address)" 0x0000000000000000000000000000000000000000000000000000000000000042

Chain and code inspection

cast block-number --rpc-url https://rpc.example
cast code 0xContract --rpc-url https://rpc.example
cast receipt 0xTxHash --rpc-url https://rpc.example
cast rpc eth_chainId --rpc-url https://rpc.example

Controlled state-changing transaction

cast send 0xContract "setValue(uint256)" 1 --rpc-url https://rpc.example --private-key 0xYOURKEY

Practical Notes

• Prefer call first; it answers a surprising amount before you risk a transaction.
• storage is excellent for proxy, slot, and state-layout triage.
• Pair with solc for compilation context and slither or mythril for deeper security review.

Caveats

• RPC and chain selection matter; wrong endpoint means wrong truth.
• send signs and broadcasts a transaction, so treat it as a deliberate action.
• ABI decoding is only as good as the signature or tuple you provide.

Resources

No bundled scripts/, references/, or assets/. Use the current Foundry cast reference for subcommand-specific flags and aliases.