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Your iOs device in a Bitcoin multi-sig

Try it on TestFlight by following the tutorial.

Use with Bitcoin Core

This is not a wallet, only a key manager. Use Bitcoin Core to download the blockchain, see your wallet balance, craft a transaction, estimate the perfect fee and broadcast it to the network once you’ve signed. It takes a little bit of effort to setup, but after that it’s easy1 to use. The tutorial will guide you through it.

Verify receive addresses

After you create a receive address in Bitcoin Core, you can verify it on the device. That way you can make sure no malware2 on your computer has been messing with it.

Check transaction before you sign

Combine multiple devices

Export and import keys

Multiple NthKey apps

You can run the app on different iOs devices, each with its own3 private keys.


You can export your public keys to Coldcard and vice versa, to create a multisig wallet with it.

Other hardware wallets

Coming soon (tm)

Known limitations


sjors@sprovoost.nl (PGP)

  1. it should be easy by the time this hits the App Store :-) 

  2. don’t push your luck though, malware can fool you in countless ways 

  3. this requires a reckless degree of trust in both the app and Apple though; always use it in combination with a different (hardware) wallet / key manager.