cast-commands

name	cast-commands
description	Interact with EVM chains using Cast CLI. Use when querying blockchain data, sending transactions, calling contracts, or converting between formats. Cast is the Swiss Army knife for chain interaction.

Cast Commands

Cast is Foundry's command-line tool for interacting with EVM-compatible blockchains.

When to Use

• Querying contract state (balances, storage, call results)
• Sending transactions
• Calling contract functions
• Converting between data formats
• Debugging transactions
• ENS resolution
• ABI encoding/decoding

Reading Contract State

call - Read-Only Function Calls

# Call a view function
cast call 0xContract "balanceOf(address)(uint256)" 0xAddress

# Call with RPC URL
cast call 0xContract "totalSupply()(uint256)" --rpc-url mainnet

# Call function with multiple return values
cast call 0xContract "getReserves()(uint112,uint112,uint32)"

balance - Get ETH Balance

# Get balance in wei
cast balance 0xAddress --rpc-url mainnet

# Get balance in ether
cast balance 0xAddress --rpc-url mainnet -e

storage - Read Storage Slots

# Read slot 0
cast storage 0xContract 0 --rpc-url mainnet

# Read specific slot
cast storage 0xContract 0x2 --rpc-url mainnet

code - Get Contract Bytecode

# Get deployed bytecode
cast code 0xContract --rpc-url mainnet

Sending Transactions

send - Write Transactions

# Send transaction
cast send 0xContract "transfer(address,uint256)" \
    0xRecipient 1000000000000000000 \
    --rpc-url mainnet \
    --private-key $PRIVATE_KEY

# Send with value (ETH)
cast send 0xContract "deposit()" \
    --value 1ether \
    --rpc-url mainnet \
    --private-key $PRIVATE_KEY

# Send raw ETH transfer
cast send 0xRecipient --value 1ether \
    --rpc-url mainnet \
    --private-key $PRIVATE_KEY

Gas Configuration

# Specify gas limit
cast send 0xContract "mint()" --gas 500000

# Specify gas price (legacy)
cast send 0xContract "mint()" --gas-price 50gwei

# Specify EIP-1559 fees
cast send 0xContract "mint()" \
    --priority-gas-price 2gwei \
    --gas-price 100gwei

ABI Encoding/Decoding

abi-encode - Encode Function Arguments

# Encode function call data
cast abi-encode "transfer(address,uint256)" 0xRecipient 1000

# Encode constructor arguments
cast abi-encode "constructor(string,string,uint8)" "Token" "TKN" 18

abi-decode - Decode Data

# Decode function output
cast abi-decode "balanceOf(address)(uint256)" 0x000...0001

# Decode with multiple outputs
cast abi-decode "getReserves()(uint112,uint112,uint32)" 0x...

calldata - Encode Full Calldata

# Encode function selector + arguments
cast calldata "transfer(address,uint256)" 0xRecipient 1000
# Output: 0xa9059cbb...

# Decode calldata
cast calldata-decode "transfer(address,uint256)" 0xa9059cbb...

sig - Get Function Selector

# Get 4-byte selector
cast sig "transfer(address,uint256)"
# Output: 0xa9059cbb

# Get event signature
cast sig-event "Transfer(address,address,uint256)"

Data Conversion

Numbers

# Hex to decimal
cast to-dec 0xff
# Output: 255

# Decimal to hex
cast to-hex 255
# Output: 0xff

# Convert to wei
cast to-wei 1.5 ether
# Output: 1500000000000000000

# Convert from wei
cast from-wei 1500000000000000000
# Output: 1.5

Units

# Parse units
cast to-unit 1000000000000000000 ether
# Output: 1

# Format units
cast to-wei 100 gwei
# Output: 100000000000

Strings and Bytes

# String to bytes32
cast format-bytes32-string "hello"

# Bytes32 to string
cast parse-bytes32-string 0x68656c6c6f...

# ASCII to hex
cast from-utf8 "hello"

# Hex to ASCII
cast to-ascii 0x68656c6c6f

Addresses

# Checksum address
cast to-checksum-address 0xaddress

# Compute CREATE address
cast compute-address 0xDeployer --nonce 5

# Compute CREATE2 address
cast create2 --starts-with 0000 \
    --deployer 0xDeployer \
    --init-code-hash 0x...

Block & Transaction Info

block - Get Block Data

# Get latest block
cast block latest --rpc-url mainnet

# Get specific block
cast block 18000000 --rpc-url mainnet

# Get block field
cast block latest --field timestamp --rpc-url mainnet

tx - Get Transaction Data

# Get transaction by hash
cast tx 0xTxHash --rpc-url mainnet

# Get specific field
cast tx 0xTxHash --field gasPrice --rpc-url mainnet

receipt - Get Transaction Receipt

# Get receipt
cast receipt 0xTxHash --rpc-url mainnet

# Get logs
cast receipt 0xTxHash --field logs --rpc-url mainnet

logs - Get Event Logs

# Get logs by event signature
cast logs "Transfer(address,address,uint256)" \
    --from-block 18000000 \
    --to-block latest \
    --address 0xTokenContract \
    --rpc-url mainnet

Chain Info

# Get chain ID
cast chain-id --rpc-url mainnet

# Get gas price
cast gas-price --rpc-url mainnet

# Get base fee
cast base-fee --rpc-url mainnet

# Get nonce
cast nonce 0xAddress --rpc-url mainnet

ENS

# Resolve ENS name
cast resolve-name vitalik.eth --rpc-url mainnet

# Lookup address
cast lookup-address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 --rpc-url mainnet

Wallet Operations

wallet - Manage Keys

# Generate new wallet
cast wallet new

# Get address from private key
cast wallet address --private-key $PRIVATE_KEY

# Sign message
cast wallet sign "message" --private-key $PRIVATE_KEY

# Verify signature
cast wallet verify --address 0xAddress "message" 0xSignature

Debugging

run - Trace Transaction

# Run transaction trace
cast run 0xTxHash --rpc-url mainnet

# Quick trace
cast run 0xTxHash --quick --rpc-url mainnet

4byte - Decode Function Signature

# Lookup function signature
cast 4byte 0xa9059cbb
# Output: transfer(address,uint256)

# Lookup event signature
cast 4byte-event 0xddf252ad...

Utility Commands

keccak - Hash Data

# Keccak256 hash
cast keccak "hello"

# Hash function signature (for selector)
cast keccak "transfer(address,uint256)" | cut -c1-10

concat-hex - Concatenate Hex

cast concat-hex 0x1234 0x5678
# Output: 0x12345678

access-list - Generate Access List

# Generate access list for transaction
cast access-list 0xContract "swap(uint256)" 1000 \
    --rpc-url mainnet

RPC Configuration

Using foundry.toml

[rpc_endpoints]
mainnet = "${MAINNET_RPC_URL}"
sepolia = "${SEPOLIA_RPC_URL}"

# Use named endpoint
cast call 0xContract "totalSupply()(uint256)" --rpc-url mainnet

Environment Variable

export ETH_RPC_URL=https://eth-mainnet.g.alchemy.com/v2/...
cast call 0xContract "totalSupply()(uint256)"

Common Patterns

See patterns.md for more examples.

Check Token Balance

cast call $TOKEN "balanceOf(address)(uint256)" $ADDRESS --rpc-url mainnet | cast to-dec

Approve and Transfer

# Approve
cast send $TOKEN "approve(address,uint256)" $SPENDER $AMOUNT \
    --rpc-url mainnet --private-key $PK

# Transfer
cast send $TOKEN "transferFrom(address,address,uint256)" $FROM $TO $AMOUNT \
    --rpc-url mainnet --private-key $PK

Interact with Uniswap

# Get reserves
cast call $PAIR "getReserves()(uint112,uint112,uint32)" --rpc-url mainnet

# Get price
cast call $ROUTER "getAmountsOut(uint256,address[])(uint256[])" \
    1000000000000000000 "[$WETH,$USDC]" --rpc-url mainnet