# Introduction to the SDK
Use User.com SDK in your own Android and iOS mobile apps.
What is User.com SDK?
User.com SDK is a set of methods and programming tools that allow for overriding custom actions and events in your Mobile Application, so it can send or receive data in the way you want.
It allows you to:
- Collect data about users and the devices they use
- Track custom events and mobile screen events
- Sending Push Notification Campaigns
- Sending In-app Messages Campaigns
What I'll find in here?
- Instructions on how to add User.com SDK to your project.
- How to create an SDK API key and Firebase Cloud Messaging key.
- Code examples (what do they do), including example data.
- Each method, endpoint and function explained.