Open-source useful tools

Closed-source softwares are not allowed in this page. Please check you can access the sources before using a program listed here, if not, warn a moderator.

Anyway, in general, never use closed-source tools when bitcoins are involved, for obvious reasons.

Client forks

piotrnar's fork

Import/export transactions

Scripts

Pywallet

Wallet managing: import/export/delete addresses and transactions, recover *coins sent to Bitcoin addresses

Sign/verify messages and files with Bitcoin addresses

Recover previously deleted key

Bitcointools

bitcoin-wallet-recover

Recover wallets from reformatted drives

Online

Blockexplorer.com (info)

List of blocks and transactions

Bitcoin Charts (info)

List of unconfirmed transaction

Bitcoin Monitor (info)

Visualize the activities on the Bitcoin network

BitAddress (info)

Generate an address and private key for an offline wallet