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An impact report from the front-lines of Bitcoin and Lightning wallet development.
BIP 329
wallet labels export, transaction labels, jsonl labels
A portable JSON Lines format for wallet labels on Bitcoin: the private notes attached to transactions, addresses, public keys, and UTXOs.
BIP 329 is a portable format for wallet labels. Labels are the notes a user attaches to transactions, addresses, public keys, and UTXOs. They are private metadata. Wallets have stored them for years, but each wallet used its own proprietary format, so switching wallets meant losing the notes.
The format is JSON Lines: one JSON object per line, each with a type, a ref, a label, and optional fields like origin and spendable. A wallet exports its labels to a .jsonl file, the user imports that file into another wallet, and the labels reattach to the same objects on the new side.
Support exists in Sparrow, BlueWallet, Nunchuk, Bitcoin Safe, and other wallets. Because the format is plain text, users can edit it by hand or back it up alongside their seed phrase without any additional tooling.