Overview
Chain utilities give you full control over your local blockchain’s state and behavior. These are essential for testing time-dependent logic, simulating edge cases, and debugging transactions.
Mining Blocks
Force mine one or more blocks:
# Mine 1 block
dokrypt chain mine
# Mine 100 blocks
dokrypt chain mine 100
- Advancing the chain after sending transactions
- Simulating block production in manual mining mode
- Testing block-dependent logic
Time Travel
Advance the blockchain’s clock without waiting:
# Advance 1 hour
dokrypt chain time-travel 1h
# Advance 7 days
dokrypt chain time-travel 7d
# Advance 30 minutes
dokrypt chain time-travel 30m
# Advance 3600 seconds (raw number)
dokrypt chain time-travel 3600
Common Use Cases
# Test a vesting cliff (6 months)
dokrypt chain time-travel 180d
# Test a timelock delay (24 hours)
dokrypt chain time-travel 24h
# Test epoch transitions (1 week)
dokrypt chain time-travel 7d
Combine time-travel with snapshots for efficient testing: snapshot before time-travel, test, then restore.
Setting Balances
Set any account’s ETH balance:
dokrypt chain set-balance 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 500
dokrypt chain set-balance 0x1234...abcd 0.5
Impersonating Accounts
Impersonate any address — transactions from this address will succeed without the private key:
# Start impersonating
dokrypt chain impersonate 0xdead...beef
# Stop impersonating
dokrypt chain stop-impersonating 0xdead...beef
- Testing admin-only functions on forked contracts
- Simulating whale behavior
- Interacting with governance contracts as specific voters
Example: Transfer tokens from a whale
# Fork mainnet
dokrypt fork mainnet
# Impersonate a USDC whale
dokrypt chain impersonate 0x47ac0Fb4F2D84898e4D9E7b4DaB3C24507a6D503
# Now you can call transfer() from this address
Setting Gas Price
Control the base gas price for testing gas-sensitive logic:
# Set gas price to 50 gwei
dokrypt chain set-gas-price 50
Resetting the Chain
Reset to genesis state or a new fork:
# Reset to genesis
dokrypt chain reset
# Reset to a mainnet fork at a specific block
dokrypt chain reset --fork https://eth.llamarpc.com --block 18000000
Chain: ethereum
Chain ID: 31337
RPC URL: http://localhost:8545
Block: 42
Timestamp: 1705312200
Multi-Chain Usage
For projects with multiple chains, use --chain to target a specific one:
dokrypt chain mine 10 --chain polygon
dokrypt chain time-travel 1d --chain arbitrum
dokrypt chain set-balance 0x1234... 100 --chain base
dokrypt chain info --chain l2
RPC Methods Used
Under the hood, Dokrypt uses these JSON-RPC methods:
| Command | Anvil Method | Hardhat Fallback |
|---|
mine | anvil_mine | evm_mine (loop) |
set-balance | anvil_setBalance | hardhat_setBalance |
time-travel | evm_increaseTime | evm_increaseTime |
set-gas-price | anvil_setMinGasPrice | hardhat_setNextBlockBaseFeePerGas |
impersonate | anvil_impersonateAccount | hardhat_impersonateAccount |
stop-impersonating | anvil_stopImpersonatingAccount | hardhat_stopImpersonatingAccount |
reset | anvil_reset | hardhat_reset |
