Designing blockchain applications for Ledger Stax and Ledger Flex

These guidelines contain best practices to design a great experience for users of your apps, whether they have a Ledger Stax or a Ledger Flex.

If you’re developing your app using Ledger’s high-level APIs and standard transaction templates, then it will already conform to these design guidelines.

Which apps are covered in these guidelines?

These guidelines apply to blockchain-related apps that fall into the standard use cases of sending crypto and NFTs, verifying addresses, or signing messages. This is the majority of apps that are available today on Ledger’s app store.

Apps with more specific needs and interfaces are not covered by these guidelines, however the general principles described here on usability and wording are a great place to start.

Ledger Stax vs. Ledger Flex, what’s different as an app developer?

Whether you start developing your app on Ledger Stax or Ledger Flex, porting it to the other Ledger device will require little to no code change, as both devices use the same APIs and graphical libraries.

The same app code scales to both Ledger Stax and Ledger Flex UI, including interaction and navigation changes.

Your app’s UI will be automatically adapted to the device model you target when building your app, dynamically adjusting the size, elements, and number of pages. This works best if you use the high-level API endpoints known as “use cases”.

Throughout these guidelines, the API endpoints will be linked within “API” sections like this:

These guidelines use screenshots and examples from both Ledger Stax and Ledger Flex. This is for variety only, as there are no functional differences between the two devices from an app developer’s perspective.

Key takeways