Startup and Baseline Profiles

Startup time is the first thing every user experiences. Google Play even surfaces slow startup as a quality issue. A fast cold start makes an app feel premium; a slow one makes users bounce.

In this lesson you will learn the three startup types, what makes startup slow, and the modern tools — App Startup and Baseline Profiles — that make cold starts dramatically faster.

Android defines three startup scenarios, from slowest to fastest:

• Cold start: the process does not exist. Android creates it, runs Application, then your first screen. The slowest and most important to optimize.
• Warm start: the process is alive but the Activity must be recreated.
• Hot start: the Activity is still in memory; just bring it to front. Nearly instant.

Optimization effort focuses on the cold start, because that is what new and returning users hit most.