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Developer utilities

Web3 Dev Tools

Everyday utilities for builders and traders. Fast, private, and they all run right in your browser.

100% client-side Nothing leaves your device

Convert between Wei, Gwei and Ether instantly. Type in any field and the others update automatically.

1 ETH = 1,000,000,000 Gwei = 10¹⁸ Wei

Sign a message with your wallet to prove ownership, or verify that a signature matches an address.

Signature

Verify a Signature

Paste a message, signature and address to check if they match.

Result

Paste raw transaction input data (hex) to see the function and parameters. Understand what a transaction does before you sign it.

Decoded
This decodes common functions (transfer, approve, etc.) by their selector. For full ABI decoding, use a dedicated tool.

Generate a wallet address that starts with letters you choose. Runs entirely in your browser — the private key never leaves your device.

Searching… 0 attempts

Address
Private Key — keep this secret!
⚠ Never share your private key. For real funds, generate keys in a trusted offline environment.

Encode constructor arguments and function calls, or decode raw calldata back into readable values. This is the tool you need when a block explorer asks for "ABI-encoded constructor arguments" during contract verification.

transfer approve (max) constructor args
Result
For explorer verification, paste the arguments only — everything after the 4-byte selector. The Encode button shows both, clearly labelled.

Pull the full verified source of any contract straight from the explorer and flatten it into one file. Multi-file and standard-JSON verified contracts come back as separate sources — this stitches them together in dependency order, deduplicates the imports and licence headers, and gives you something you can paste into Remix.

Reading the verified source…

Contract
Flattened source
Only works on contracts that are already verified on the explorer. An unverified contract has no source to fetch — which is itself worth knowing before you interact with it.

Build a holder list for any token — every wallet and its live balance — for an airdrop, a governance vote, or a migration. The list is reconstructed from the token's transfer history, then every candidate's balance is read fresh from the chain, so what you get is current rather than a stale index.

Reading transfers…

Snapshot
Top holders
Reconstructed from the last 10,000 transfer events, which covers most tokens completely. A very high-volume token may have older holders who never appear in that window — the summary tells you when the history was truncated so you know whether to trust the total.

The four numbers people get wrong when planning a launch: what a market cap implies for price, what a price implies for market cap, how much a position is worth at a target, and what your slippage actually costs.

📈

Market cap ↔ price

🎯

What would my bag be worth?

💧

What slippage really costs

The slippage figure is the constant-product (Uniswap V2) formula, which is the honest worst case for a plain pool. A V3 pool with concentrated liquidity behaves better inside its range and worse outside it — treat this as the ceiling, not the quote.