LDK toolkit for adding Lightning to your own app

Swiss angle

LDK is a global project. The Spiral projects page, read on 4 October 2026, says Spiral built the Lightning Development Kit "so that anyone could integrate bitcoin's Lightning network without asking permission". The Spiral home page says Spiral was founded as a Block initiative for the public good. Spiral publishes code and holds no customer coins, so it is not a financial service.

We found no Swiss office or Swiss user named on the project's own pages, so this listing claims none. For a reader in Switzerland, LDK changes the same thing as anywhere else: the wallets built on it can be self-custodial, which means the coins stay yours and you declare them yourself at year end, as the Swiss Bitcoin tax guide explains.

If Lightning itself is new to you, read the Lightning Network chapter first. LDK only makes sense once channels, invoices and routing are familiar words.

Who it is for

Developers who want Lightning inside an app they already have. The LDK home page calls it "a complete Lightning implementation packaged as an SDK" and says you can run a Lightning node "on mobile, web, HSMs, LSPs, or your existing infrastructure". You choose how storage, chain data, networking and key management work, and LDK handles the protocol.

Teams who need a library rather than a finished node. The rust-lightning README says that "LDK isn't, in itself, a node", and points to LDK Node for a ready-made version. The same README says the project implements all of the BOLT specifications and has been in production use since 2021.

Builders who want to see who else took this route. The LDK case studies page lists Alby Hub, Cash App, Lexe, Lightspark, Bitkit and Zeus among the projects building with it.

The code is free to use in commercial products. The rust-lightning README says the licence is Apache-2.0 or MIT, at the option of the user. The README is on a GitHub mirror; the repository description says active development happens on git.rust-bitcoin.org.

Who it is not for

Anyone who wants a Lightning wallet to install today. LDK is a toolkit for programmers and has no app for you to download. Start with the wallet listings instead; the Phoenix listing covers a Lightning wallet you can use without writing code.

People who want to run a routing node at home with a few clicks. A home server such as Umbrel is the shorter path, and the Lightning home setup guide walks through it.

Developers who are not ready to keep channel data safe themselves. The rust-lightning README notes that, as with any Lightning implementation, safe deployment needs care and attention to detail, and losing channel data can cost channel funds.