The Android app is written in Kotlin and Java. The most current information on supported devices and Android versions is available on the Device Compatibility page.
The iOS app is written in Swift and Objective-C. The most current information on supported devices and iOS versions is available on the Device Compatibility page.
The patron web application is implemented with the React framework and is written in TypeScript.
The administrative UIs for the Palace Collection Manager and Library Registry are implemented using the React framework and written in TypeScript.
The Palace Collection Manager and Library Registry are implemented in the Flask framework and are written in Python 3. Both of these applications depend on a PostgreSQL database. In addition, the Collection Manager depends on ElasticSearch.