Muhammad Ahmad Khan

Exergy Systems · Lahore

Java · Spring Boot · AWS · React · Flutter · Android

• Architected Spring Boot microservice APIs across orders, payments, inventory and referrals on AWS RDS; optimized JPA queries and data models for mobile/web clients.
• Integrated JazzCash, Etisalat, UBL and Meezan Bank gateways with idempotency and HMAC-SHA256 webhook verification, ensuring 99.9% payment state consistency.
• Reduced API latency 93% (30s → 2s) for 1,000 concurrent users and 20K–30K records using Redis caching, CloudFront and REST optimization.
• Reduced technical debt and system errors 40% by standardizing Builder, Factory, Singleton and Observer patterns across shared services.
• Constructed resilient background upload services with retry logic and state management, reducing upload failures 95% on low-connectivity networks.
• Delivered the full client side end to end — Flutter and Android apps (iOS/Android) and a React dashboard for order, inventory and refund management, including native plugins, reusable components, data tables and dashboards wired to the Spring Boot APIs.
• Implemented voucher, discount and referral bonus logic with atomic transactions to prevent double-spend and race conditions.
• Scaled AWS infrastructure with Redis, SMS failover, AES encryption and S3 migration, improving uptime and reducing single points of failure.
• Directed technical delivery for up to 10 engineers — sprint planning, code reviews, CI/CD pipeline management and system architecture decisions — sustaining 90%+ on-time release cadence.

Exergy Systems · Lahore

• Shipped 5+ high-performance Android apps in Java/Kotlin with sub-200ms UI response times and less than 0.5% ANR rate.
• Developed 10+ native Android and Flutter features integrating REST APIs and SDKs with consistent UI state and offline behavior.
• Mentored engineers and led Java, Spring Boot, Flutter and Android code reviews; coding standards cut onboarding time 30% and reduced regressions.
• Led mobile architecture for 3 major projects, managing complex integrations and release decisions.
• Improved stability through performance tuning and critical bug fixes, reducing ANR and critical issues 15%.

Pioneer Tree Technologies · Lahore

• Launched 6 Android apps to 100,000+ downloads, 4.2+ ratings and 50,000+ monthly users within 6 months.
• Integrated MFA across Firebase, Google OAuth, Facebook SDK and SMS Retriever; achieved 99.8% login success and 40% faster login.
• Integrated 20+ SDKs including AdMob ($5,000+/month), FCM and OneSignal, generating 500,000+ push notifications/month with 65% open rate.

TALEEM Consultancy · Lahore

• Engineered and shipped 3 education Android apps with 4.0+ ratings across architecture, development, Play Store release and maintenance — all delivered on schedule.
• Partnered with designers and curriculum experts to release 10+ interactive learning modules, increasing average session duration 20%.