KSP: The Future of Kotlin Annotation Processing

Kotlin Symbol Processing (KSP) is an API that you can use to develop lightweight compiler plugins. KSP provides a simplified compiler plugin API that leverages the power of Kotlin while keeping the learning curve at a minimum. Compared to kapt, annotation processors that use KSP can run up to 2 times faster.

Kotlin Kapt and KSP are both annotation processors that allow you to use Java annotation processors with Kotlin code. However, there are some key differences between the two:

• KSP is faster. KSP analyzes Kotlin code directly, which is up to 2x faster than kapt, which needs to generate Java stubs first.
• KSP has a better understanding of Kotlin. KSP understands Kotlin-specific features such as top-level functions and nullability, which kapt does not.
• KSP is more idiomatic Kotlin. The API for KSP processors is more Kotlin-like, which makes it easier to write and maintain KSP processors.
• KSP is the future of Kotlin annotation processing. Kapt is now in maintenance mode, and we recommend migrating from kapt to KSP wherever possible.

If you are using Kotlin, I recommend using KSP instead of Kapt. KSP is faster, has a better understanding of Kotlin, and is the future of Kotlin annotation processing.To use KSP instead of Kapt, you need to do the following:

1. Check the libraries you use for KSP support. Not all libraries support KSP yet, so you need to check the documentation for each library to see if it supports KSP.
2. Add the KSP plugin to your project. This can be done by adding the following line to your build.gradle file:

apply plugin: 'kotlinx-ksp'        

1. Replace annotation processors with KSP. This means changing the annotation processors that you use in your code to KSP-compatible processors.
2. Remove the kapt plugin. Once you have migrated to KSP, you can remove the kapt plugin from your project.

Here are some additional resources that you may find helpful:

• Why KSP: https://kotlinlang.org/docs/ksp-why-ksp.html
• Migrate from kapt to KSP: https://developer.android.com/build/migrate-to-ksp
• KSP documentation: https://kotlinlang.org/docs/ksp-overview.html
• Youtube: https://youtu.be/bv-VyGM3HCY?si=GisRS5Ua4hbjQX99