Baseline Profiles for Fast Startup
Precompile hot paths for smooth launches.
Baseline Profiles for Fast Startup is a free Jetpack Compose Academy lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Jetpack Compose Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Why Startup Feels Slow
Fresh app code runs interpreted at first, then compiles in the background. Those early frames are the slowest, and users feel them as a sluggish launch.
What a Baseline Profile Is
A baseline profile lists the hot code paths your app runs at startup. Android precompiles them at install time, so they are fast from the first tap.
The Payoff: Faster Frames
With a profile shipped, startup and the first scrolls run ahead-of-time compiled. Real apps often see launch times improve by twenty to thirty percent.
How It Gets Generated
You do not write the list by hand. A Macrobenchmark test exercises your key flows, and the tooling records which methods and classes were used.
Add the Baseline Profile Plugin
Generation is driven by the baselineProfile Gradle plugin and a companion module. It runs your benchmark and writes the profile into your app.
plugins {
id("androidx.baselineprofile")
}Write a Collection Test
In the test you call collect and drive a critical journey, like launching and scrolling the home list, so the right paths are captured.
baselineProfileRule.collect(
packageName = "com.app"
) { startActivityAndWait() }Where the Profile Lives
The generated file lands in src/main/baseline-prof.txt. It ships inside your app bundle and Android applies it during install.
Profiles Are Versioned
Your code changes, so regenerate the profile when hot paths shift. A stale profile still helps, but a fresh one captures your latest startup flow.
Quick Check
A teammate asks how baseline profiles speed up launch. What is the core mechanism?
Verify the Win
Re-run your Macrobenchmark with the profile applied and compare startup timings. Numbers, not guesses, prove the improvement is real.
Startup Profiles Too
You can also mark the most launch-critical paths as a startup profile. Android prioritizes compiling those first for the snappiest possible cold start.
It Just Ships, No Setup
Best of all, users do nothing. The profile is applied automatically during install, so the speed boost arrives the first time they open your app.
Recap: Compile the Hot Paths
You generated a baseline profile from a benchmark, shipped it in your bundle, and measured a faster, smoother launch.
Frequently asked questions
Is the “Baseline Profiles for Fast Startup” lesson free?
Yes — the full text of “Baseline Profiles for Fast Startup” is free to read here on the web, and the Jetpack Compose Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Jetpack Compose Academy course, upgrade to CoddyKit PRO.
What will I learn in “Baseline Profiles for Fast Startup”?
Precompile hot paths for smooth launches. You practise Jetpack Compose Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Jetpack Compose Academy?
No prior experience is required. Jetpack Compose Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Baseline Profiles for Fast Startup” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Jetpack Compose Academy lesson?
Yes. Every Jetpack Compose Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Accessibility & Edge-to-Edge UI
- Baseline Profiles for Fast Startup
- Signed Release App Bundle
- Compose Multiplatform-Ready Architecture