--- title: "Tinder cuts app cold starts by 47% with new R8 Configuration Analyzer" url: https://daily.dev/posts/tinder-cuts-app-cold-starts-by-47-with-new-r8-configuration-analyzer-gqlbazjn8 source_url: https://android-developers.googleblog.com/2026/08/tinder-app-cold-start-r8-configuration-analyzer.html type: article source: "Android Developers Blog" published: 2026-08-18T18:01:32.904Z updated: 2026-08-18T18:24:35.394Z tags: ["android"] reading_time: 5 upvotes: 1 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Tinder cuts app cold starts by 47% with new R8 Configuration Analyzer **[Android Developers Blog](https://daily.dev/sources/androiddev)** · 5 min read · 1 upvotes · 0 comments ## Summary Tinder's Android team used the new R8 Configuration Analyzer to identify and fix overly broad keep rules that were blocking code optimization. An in-house library's unscoped keep rule was preventing R8 from optimizing large parts of the app. After refining it, Tinder cut cold starts by 47%, reduced APK size by 28.98% (to 61.5 MB), lowered user-perceived ANRs by 28%, and raised their R8 optimization score from 28% to 50%. The team also added CI/CD monitoring to prevent future regressions and published an R8 Analyzer skill for use with agentic tools. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is the R8 Configuration Analyzer for Android and what does it show? The R8 Configuration Analyzer is a tool that reports shrinking, optimization, and obfuscation scores for an Android app's R8 configuration. It surfaces broad, redundant, or obsolete keep rules, including ones introduced by external libraries, so developers can audit and refine keep rules to unlock more code optimization and smaller, faster apps. _Track new Android tooling like the R8 Configuration Analyzer as it evolves via daily.dev._ ### How much did Tinder improve app performance by fixing R8 keep rules? Tinder cut cold starts by 47%, shrank app download size by 28.98% down to 61.5 MB, and reduced user-perceived ANR errors by 28%. The gains came from finding a broad in-house library keep rule that blocked optimization across many classes; fixing it raised their R8 optimization score from 28% to 50%. _Developers chasing similar cold-start wins can follow real-world R8 case studies on daily.dev._ ### Why do overly broad R8 keep rules hurt Android app optimization? A wide keep rule like `-keep public class * { public protected *; }` prevents R8 from shrinking or optimizing any class it covers, even unrelated dependencies, because it blocks removal of unused code and members. Such rules often come from internal libraries assumed to be safe, silently blocking optimization across an entire codebase without causing crashes. _Anyone debugging bloated keep rules can find practical R8 tuning examples on daily.dev._ ## Similar posts on daily.dev - [How Reddit used the R8 optimizer for high impact performance improvements](https://daily.dev/posts/how-reddit-used-the-r8-optimizer-for-high-impact-performance-improvements-06qzize75) · Android Developers Blog · 0 upvotes · 0 comments - [Android Developers Blog: Configure and troubleshoot R8 Keep Rules](https://daily.dev/posts/android-developers-blog-configure-and-troubleshoot-r8-keep-rules-93owf7hzc) · Android Developers Blog · 1 upvotes · 0 comments --- Tags: [#android](https://daily.dev/tags/android) [View this post on daily.dev](https://daily.dev/posts/tinder-cuts-app-cold-starts-by-47-with-new-r8-configuration-analyzer-gqlbazjn8)