Japan-based startup Nayuta has released what it says is the first lightning network wallet with a built-in bitcoin "full node."

Lightning is the scaling technology trumpeted as the future of bitcoin payments. With the new Nayuta Android app, users can tap into the new payment system in one of two ways: by using the baked-in bitcoin "full node" for added security or they can switch to a "SPV" version (Neutrino), which isn't quite as secure, but takes up much less space on the phone.

Nayuta claims it is the first developer to add a full node to its wallet, making the esoteric sovereignty-preserving technology a bit easier to use. They use a fork of the project ABCore, which makes it easier to run a full node on Android devices.

"Using a full node is the only way to really know if you received bitcoin, if you don't use a full node you are always trusting somebody to a degree, whether that would be the wallet company's node or the miners," said Christian Moss, Nayuta's mobile app developer.

Full nodes can take hours to download, but they're the most secure way of using bitcoin as the user doesn't have to trust anyone to ensure they have the correct transaction data. Making a full node easy to run has long been a primary goal for many bitcoin developers.

"For day-to-day, it is definitely more convenient and practical to use the wallet without the full node. However it is important to have the full node available in case the network were attacked in a similar fashion to Segwit2x with miners producing invalid blocks," Moss said.

In addition to allowing users to choose either a full node or a SPV node running in the background, there's a third "hybrid" mode, which allows the wallet to automatically bounce between the two.

"With hybrid mode, during the day when you are outside your wallet gets blocks from Neutrino [the SPV wallet], and at night when your phone is charging, having wifi, and [the bitcoin full node] is running it will check those blocks are valid," said Nayuta CEO Kenichi Kurimoto.

He hopes this is a good way to get the best of both worlds.

"In the bitcoin space, only a fully [validating] node is the perfect solution for self-sovereignty. On the other hand, the SPV node is superior for storage size, internet connection bandwidth, and power consumption. We think that there may exist a new good solution to this trade-off problem. Nayuta mobile wallet hybrid mode is one such solution," he said.

Moss is optimistic it will only get easier to run a bitcoin full node on a mobile device over time.

"Whilst this current implementation of a full node lightning wallet is not as super user-friendly we think that research and development in this direction is a no-brainer for bitcoin. [In] the future, as smartphones become more powerful, running a full node could have a similar UX experience as running a light client wallet," he said.