Imagine: a user opens your app, sees a white screen for 4 seconds, and then a frozen list. That’s not a bug—it’s a systemic performance problem. On the App Store, apps with slow startup get ratings below 4.0, and retention drops by 20% in the first minute. A performance audit is not a one-time check; it’s a methodology for collecting and analyzing metrics: launch time, rendering, memory, network, and battery. We, engineers with 5+ years of experience, conduct audits on real devices and deliver a prioritized report with measurable recommendations. Without data, you guess—with the report, you know exactly what to fix and what effect to expect.
For instance, on one project we reduced cold launch from 4.2 s to 380 ms by removing synchronous initialization of four SDKs from the AppDelegate. This increased registrations by 7%. Want the same for your app? Keep reading.
What Metrics Do We Measure?
We focus on five aspects that directly impact user retention and store ratings.
Launch Time
iOS: XCTest with measure(metrics:) + XCTApplicationLaunchMetric. We separate cold launch (first launch after reboot) from warm launch (subsequent). Apple recommends cold launch < 400 ms to first frame. Typical problem: static initialization in AppDelegate—multiple SDKs, databases, analytics—all synchronous on the main thread.
Android: adb shell am start -W com.package/.MainActivity—outputs TotalTime and WaitTime. Firebase Performance Monitoring automatically collects app_start. Common cause of slow start: early initialization of Room/Realm in Application.onCreate(), synchronous SharedPreferences read.
Memory
iOS: Xcode Memory Graph + leaks. We look for retain cycles (closure captures self, self holds the closure). os_signpost for markers.
Android: Memory Profiler in Android Studio, Heap Dump. We check for Leaked Activities (Activity not destroyed due to static reference), oversized Bitmaps (incorrect inSampleSize).
Rendering
iOS: Instruments → Core Animation. Offscreen-rendered content—unnecessary CALayers, Color blended layers—overdraw.
Android: adb shell dumpsys gfxinfo com.package framestats. Slow frames > 5%—a problem. systrace or Perfetto.
Network
Charles Proxy or mitmproxy. We check: duplicate requests, lack of caching, large payloads (JSON without pagination, uncompressed images), absence of HTTP/2.
Battery
iOS: Xcode Energy Impact + MetricKit. Android: Battery Historian (adb bugreport).
Why Is a Performance Audit Profitable?
Reducing launch time by 300 ms increases registration conversion by 3-5% (industry studies). Reducing slow frames from 10% to 1% boosts store ratings by 0.3-0.5 points. An audit delivers measurable ROI: you invest 3-10 days of your team and get metric improvements, competitiveness, and reduced support load. Average budget savings on rework—from 15%. The audit pays for itself within 3 to 6 months by reducing bug-fixing and maintenance time.
How We Conduct the Audit: Step by Step
- Collect baseline metrics. We automatically gather Firebase Performance, Sentry Performance, or custom instrumentation. We look at P50/P75/P95 for launch time, screen render, and HTTP latency on real users.
-
Analyze code. Static analysis of key paths:
onCreate/viewDidLoad, rendering methods, network layer, database work. We look for synchronous operations on the UI thread, non-optimal queries, lack of debounce. - Reproduce on devices. Two to three devices: flagship, mid-range, low-end. Problems on flagships often are not reproducible, but 30–40% of the audience uses mid-range or older devices.
- Form the report. We create a problem table with priorities, reproduction steps, screenshots, and recommendations. We attach metric distribution charts and before/after comparisons.
What Does the Report Include?
Based on the audit, you get a document with a problem table:
| Problem | Metric | Device | Priority |
|---|---|---|---|
Synchronous DB read in onCreate |
+340 ms to cold start | Samsung A54 | High |
| 8 parallel requests on startup | 600 ms TTFR | All | High |
| Retain cycle in ProfileViewController | +12 MB leak per session | iOS | Medium |
| Overdraw in FeedCell | 15% slow frames | Pixel 6a | Medium |
Each problem includes reproduction steps, screenshots, and a recommendation. Additionally, we provide: source code with measurements, metric distribution charts, before/after comparisons.
Typical Performance Problems
- Static SDK initialization on the main thread - Lack of pagination when loading lists - Retain cycles due to closures on iOS - Synchronous database operations on Android - Excessive redrawing of nested RecyclerViewsAudit Timeline
| App Size | Duration |
|---|---|
| 10–30 screens | 3–5 working days |
| Large (multiple modules) | 7–10 working days |
Exact timeline is calculated individually after reviewing the project. Order an audit now—get a prioritized report within 3-5 days. Contact us for a preliminary assessment of your project.
We guarantee code and data confidentiality. Experience with apps in fitness, banking, marketplaces, edtech. Order an audit, and we'll show you how much faster your app can run.
According to iOS Performance Guidelines from Apple, cold launch should not exceed 400 ms.