Global architecture

Let’s see the typical end-to-end architecture of a BOLOS application, in the case of an app for a cryptocurrency:

End-to-end architecture of a BOLOS application

Three pieces of software are required:

• A BOLOS application, written in C, running on a Ledger device
• The wallet app with business logic and typically a GUI, running on a computer or a phone connected to the Ledger device
• A transaction explorer that interfaces between the front-end and the cryptocurrency daemon, running either locally (in the case of a full node) or remotely (light wallet)

If you’re not developing an app adding support for a cryptocurrency, then you can ignore the 3rd piece. Depending on your use case, the wallet app might be a simple daemon or a command line tool, without a GUI.

The Ledger Manager is the service which centralizes the distribution of BOLOS applications on Ledger devices. It is the place where both Ledger’s apps and third party apps are distributed to users.

The Ledger Manager