the free web3 dev toolbox
your #1 spot for evm dev tools. free, instant, private.
what each tool does
On-chain
transaction inspectorpaste a tx hash: chain found automatically, everything decoded.- stuck transaction fixerwhy is my tx pending? find out, then speed it up or cancel it with the right gas.
- raw transaction decoderdecode a signed raw tx: sender, nonce, fees, calldata, hash. then broadcast it.
contract inspectorwallet or contract? proxy implementation, clones, 7702, token info.
ENS lookupname ↔ address, avatar, x, github and website records.
ABI & calldata
selector & topic calculatorsignature → 4-byte selector, event topic0, error selector. and back.
calldata decoderpaste tx input data, get the function and every argument, decoded.
revert reason decoderturn 0x08c379a0… and panic codes into plain english.
ABI encodersignature + arguments → calldata, abi.encode or encodePacked.
ABI to interfacepaste an abi, get a solidity interface with structs.
event log decoderpaste a log or a whole receipt, get every event decoded.
Hashing & encoding
Storage & deploys
storage slot calculatormapping and array slots, erc-7201 namespaces, proxy slots.
contract address calculatorpredict deploy addresses from deployer + nonce, or salt + initcode.
merkle tree builderallowlist or airdrop rows → root and proofs, openzeppelin style.
bytecode disassemblerbytecode or address → opcodes, functions, compiler, red flags.
storage layout & packingsee every slot, find wasted bytes, get an order that saves gas.
Units & gas
unit converterwei, gwei, ether, and any decimals: usdc 6, wbtc 8.
gas cost calculatorgas units × live gas price → cost in eth and usd, per chain.- gas refuelout of gas on a new chain? bridge a little from where you have some, in one tx.
live gas trackerlive gas on 13 chains, what a transfer costs, cheapest chain now.
HyperEVM
HyperEVM big blockscheck and switch an address between big and small blocks.- HyperCore precompile readercall any L1Read precompile live, with the numbers scaled for humans.
- CoreWriter action builderbuild sendRawAction bytes for orders, transfers, staking. or decode a tx’s actions.
- Core ↔ EVM bridge resolverany token’s system address, evm contract and decimals, plus the exact transfer to send.
Robinhood Chain
Addresses, signatures & time
address checksumvalidate an address and get its eip-55 checksum.
unix timestamp converterblock.timestamp ↔ date, durations in seconds, relative time.
signature verifierwho signed this? personal_sign, eip-712, split and compact.
Safe transaction hashcheck the safeTxHash your ledger shows before you sign. batches decoded.
need the contracts, not just the tools?
solidity for apps & games: foundry-tested, gas-aware, handed over with docs.