Context: Android VPN app with high traffic. ~70% users are in Iran, ~30% rest of world. Using AdMob mediation (bidding + waterfall) with Rewarded Interstitial / Interstitial / Banner. Current issues: High requests but very low impressions (large portion is No Fill / Empty). Low match/fill rate and weak eCPM, especially in Iran. Some mediated networks rarely show ads or don’t serve at all. (Attached dashboard sample: 500K+ requests / ~41K impressions in 7 days, Match ~41%, overall eCPM ~AED2.14; format breakdown included.) Objectives: Identify the root causes of No Fill / mediation not serving. Increase fill/match rate and eCPM via technical fixes + mediation strategy. Deliver a diagnostic report, actual fixes (dashboards + code), and a test build. Deliverables: Full AdMob/Mediation audit (waterfalls, bidding, floors & currency, geo targeting, block lists, Iran eligibility, Families/TFUA, app-ads.txt, etc.). SDK/adapter upgrades and Android build fixes (ProGuard/R8, Gradle), plus review of timeouts, callbacks, caching, preload & show timing. Geo-specific optimization for Iran vs RoW (separate ad units, floors, caps/refresh, category restrictions). Instrumentation & logs for mediation error codes (NO_FILL, MEDIATION_NO_FILL, timeouts) and before/after metrics. Short documentation of changes and maintenance tips. Access (read-only is fine): AdMob + mediated networks, Firebase/Analytics, Android repo (read), and Play Console read if needed. Success Metrics (KPIs): Raise fill/match rate in Iran to 60–70%+ (or +20% absolute improvement). Increase eCPM for Rewarded/Interstitial in Iran & key markets. Higher Impressions/Requests ratio and improved daily revenue. Required expertise: Deep AdMob Mediation knowledge (bidding & waterfall), policies, Families/TFUA, UMP/GDPR. Hands-on with networks that serve Iran and practical No-Fill workarounds. Android (Kotlin/Java), Gradle, Play Console, mediation log analysis. Please answer in your bid: Similar projects & results (especially in Iran). Your approach to isolate No Fill causes (geo/policy/adapter/timeout). Networks/strategy you recommend for Iran. ETA for initial audit and test build.