Client SDKs

The client side SDK and fingerprinting is a core component of a Castle integration that enhances Castle's ability to detect fraudulent and malicious abuse of in-application activity.

All the client-side SDKs, have two main purposes:

  • Creating request tokens – A unique token which should be passed to the server whenever Castle's backend APIs are called.
  • Tracking client-side event – Track important in-app events directly from the client to get a granular view of the user journey


The client-side integration is required in order to use the Risk and Filter APIs as they require the request_token field to be populated.

Castle offers client-side SDKs for both web and native mobile apps. Pick the client-side Castle integration that you want to learn more about: