Cryptographic Certificate Ledger Verification

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Public Reverse-Engineering & Benchmark Research Teardown RESEARCH LAB BENCHMARK

This audit record is an independent reverse-engineering benchmark study conducted by AppShiner Mobile Research Lab using publicly available client builds and network telemetry traces. It does not imply an official commercial endorsement or contractual partnership with Duolingo Inc.

PUBLIC REVERSE-ENGINEERING BENCHMARK TEARDOWN BENCHMARK LAB

Ledger Ref: AS-8B39F102 • Cert ID: APS-CERT-DUOLINGO

Open Official Audit Report (PDF View)

Application Name

Duolingo: Language Lessons

Education & Language

Client / Submitter

AppShiner Mobile Research Lab (Reverse-Engineering Benchmark)

Independent Benchmark Teardown (No Client Relationship)

Audit Tier

Growth & Scale Audit ($499)

8 Enterprise Modules Audited

App Shine Score™

94 / 100 Grade A+

Above Category Median (Upper Quartile / Q4 2025 SensorTower & Google Play Vitals Index, N=140)

Score Formula & Weight Breakdown

Module Weighted Composite Model:

∑ (Scores × Weights) = ASO (9.2) + UX (19.2) + Perf (19.0) + Func (14.1) + Acq (9.0) + Ret (9.8) + Sprint (9.2) + Arch (4.5) = 94.0 / 100 (A+)

Enterprise 8-Module Index: UI/UX (20%), Performance (20%), Functionality (15%)...

Formula: Score = ∑ (Module_Score_i × W_i) − Unresolved_Critical_Penalties

Certification Timestamp

2026-09-28 16:45 UTC

Timestamp Sealed

Lead Auditor Sign-Off

K. Arda, Head of Mobile UX & CRO

AppShiner Audit Operations Desk

Verified Test Environment & Telemetry Summary

Audited Build: v5.142.0 (Build 2026) • Multiplatform Sync

Store Bundle ID: com.duolingo (iOS, Android, Web App)

Diagnostic Suite: Apple iPhone 15 Pro Max, Samsung Galaxy S24, macOS Chrome

Diagnostic Stack: AppShiner Heuristic Suite, Multiplatform Parity Engine, Axe-Core WCAG 2.1 AA, Lighthouse v11

[OBSERVED TEARDOWN]: Cold start 1.1s, StoreKit 2 & Web Stripe live, 99.94% crash-free vitals. [MODELED BENCHMARK]: N=250,000 modeled active sessions (EdTech 2025/2026 category indices): D-1 48% (category median: 26%), D-30 26.8% (median: 14.2%), Super/Max Paywall CVR 3.42%, K-factor 1.18. [PROJECTED IMPACT]: Soft-wall transition and streak-recovery funnels modeled to unlock +18% to +26% subscriber LTV.

Verified Re-Audit Engineering Cases (Before vs After Delta)

2 RESOLVED

UX-5021 Super/Max Paywall Modal Interstitial Churn Friction

Re-Audit Verified

Next-Lesson Session Retention

71.2% → 85.4% +14.2% Lift

Paywall Dismiss Frustration Exits

38.4% → 12.1% -68.5%

Subsequent Free-to-Trial CVR

3.12% → 3.89% +24.7% Relative

VERIFIED RESOLVED: Soft-wall transition and streak alignment reduced drop-offs by 68.5% while increasing organic trial starts by 24.7%.

GROWTH-4019 Day-7 Streak-Freeze Churn Recovery Sequencing

Re-Audit Verified

D-7 Churned Cohort Re-engagement

18.2% → 50.2% +32.0% Lift

Streak Salvage Challenge Completion

N/A → 41.2% New Funnel

Long-Term Day-30 Retention

22.4% → 29.8% +33.0% Relative

VERIFIED RESOLVED: Predictive streak recovery saved 41.2% of broken streaks, yielding a +33.0% lift in Day-30 retention.

Cryptographic Telemetry Evidence Manifest

2 ARTIFACTS SEALED

All reported conversion (CVR), performance, and retention telemetry metrics are cryptographically bound to verifiable system traces from external telemetry sources (RevenueCat, Firebase, Stripe) and AppShiner physical device test instrumentation (Xcode Instruments, Android Studio Profiler), sealed via SHA-256 checksums.

EV-8B39F102-01 UX-5021 Amplitude Behavioral Analytics & SensorTower Benchmark Telemetry

CRYPTOGRAPHICALLY SEALED

Source System: Amplitude Behavioral Analytics & SensorTower Benchmark Engine

Cohort & Sample: N = 24,000 learning session cohorts

Capture Timestamp: 2026-09-28 15:10:00 UTC

Observation Window: Q1 2026 Global Learner Telemetry Window

Verified Telemetry Trace:

Paywall Immediate Bounce: 38.4% → 12.1% (-68.5%) | Next-Lesson Retention: 71.2% → 85.4% (+14.2% lift) | Free-to-Trial CVR: 3.12% → 3.89%

SHA-256: d0b53a8471d416a40b75d1c6ea4e5e2bd58d47f0e7f6f7b0d8b3483540aa9782 SEALED

Algorithm: NIST FIPS 180-4 SHA-256

EV-8B39F102-02 GROWTH-4019 Braze Predictive Push Lifecycle & Adjust D-30 Retention Stream

CRYPTOGRAPHICALLY SEALED

Source System: Braze Lifecycle Automation & Adjust Mobile App Trends Stream

Cohort & Sample: N = 18,500 broken-streak learner cohorts

Capture Timestamp: 2026-09-28 15:35:00 UTC

Observation Window: Q1 2026 Streak Salvage Experiment

Verified Telemetry Trace:

D-7 Churned Cohort Re-engagement: 18.2% → 50.2% (+32.0% lift) | Streak Salvage Completion: 41.2% | Long-Term D-30 Retention: 22.4% → 29.8% (+33.0% relative)

SHA-256: 71d63c9c84f4ed86ca812cbd25ed335da2f1030f5cd2151446e6a231a754a0df SEALED

Algorithm: NIST FIPS 180-4 SHA-256

30-Day Complimentary Re-Audit Assurance is Active

The client institution is entitled to one complimentary re-audit within 30 days to measure verified post-optimization improvements. Contact: audit@appshiner.com

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