Tools
28 free tools for building on Ethereum, Base and every other EVM network. Nothing to install, no account, and everything but the launchers runs entirely in your browser.
Start here
Most used
Wallets & keys
Make throwaway wallets, sign messages, check an address is real.
Throwaway wallet
Generate a brand-new wallet and private key in your browser, for testing.
Sign & verify a message
Prove you own a wallet by signing plain text, or check whether a signature is genuine.
Sign structured data
Sign a structured request — a permit, an order, a vote — the way apps ask wallets to.
Fix an address
Convert an address to its official capitalisation and catch a typo before you send funds.
Find an address by its characters
Search live explorer data for real, active addresses starting or ending with the characters you remember.
Inspect & decode
Read what a transaction did and call a contract's functions.
Convert & calculate
Units, hashes, timestamps and number formats. Instant, as you type.
ETH & gas converter
Convert between wei, gwei and ether, and price a transaction in ETH.
Hash generator
Hash any text with keccak256, sha256 or sha512 as you type.
Timestamp converter
Turn a Unix timestamp into a readable date, and back again.
Number converter
Move a number between decimal, hexadecimal and binary.
Text & bytes converter
Convert text to hex bytes and back, including fixed-size bytes32 values.
Bitwise calculator
Shift and mask 256-bit numbers — AND, OR, XOR, NOT and bit shifts.
Merkle tree builder
Build an allowlist: paste addresses, get the root to publish and a proof for each one.
ENS names
Turn a .eth name into an address, and see what a name stores.
Prices & DeFi
Work out what a Uniswap pool says a token is worth.
Contract safety
Check a contract follows the rules before you trust it with money.
Token standard checker
Paste a contract and see whether it really implements ERC-20, 721, 1155 or 4626.
Invariant test generator
Generate Foundry invariant tests and handlers from a contract you paste in.
Contract property analyzer
Find the state variables and rules worth asserting before an audit.
Fuzz coverage viewer
Load an Echidna or Medusa coverage file and see which lines were never hit.
Trace to test converter
Turn a failing fuzzer trace into a Foundry test that reproduces it.
Reference
Addresses worth keeping and answers worth looking up.
Networks these work on
Plus every matching testnet, and any other EVM chain you point the launchers at by id and RPC.
"This is the best product ever when it comes to shipping. Ten on ten recommended. I just can't wait to see what happens with this product."
Michael Scarn
Side projects builder