Muun review

Muun is the simplest way to hold bitcoin and Lightning as a single balance on a phone, and two things about it are unusual enough to understand before you install it: your backup is a file, not a word list, and the company has published almost nothing since 2021. Payments go out over whichever layer fits, so you never pick a rail before paying, and Muun's fee estimator reads the mempool rather than a fixed table, which the team documented in a post explaining where the savings come from.

The security model is a 2-of-2 multisig. Every outgoing transaction needs two signatures, your phone holds one key, and Muun holds the other. A thief with your unlocked phone therefore cannot spend, and neither can Muun on its own. The part people miss is the backup: the Emergency Kit you export contains both keys plus the output descriptors that describe the scripts your coins live in, so recovery never depends on Muun still being there. That also makes the kit the whole wallet. Anyone who gets the file and your recovery code gets your bitcoin, so it belongs on paper somewhere safe rather than in your email.

Muun does not use a twelve word seed phrase, and it published its reasoning: a mnemonic backs up keys, while Muun's coins sit in multisig, Lightning and taproot scripts that a wallet also has to be told about. Recovery comes in two shapes, a Cold Recovery Code written on paper, or email plus password plus recovery code.

The caveat is maintenance. The most recent post on Muun's blog was written days before taproot activated in November 2021, and two features it once announced carry edit notes saying they were switched off, the Lightning node top up in June 2020 and the Trezor transfer in September 2020. The apps are still shipping and still work, but a project this quiet is a spending wallet rather than a place to leave savings for years. The other thing to plan for is fees: payments that need a submarine swap settle on chain, and when the mempool is busy that costs real money.