ASHEESH KUMAR SAHULead Engineer · Mobile & Web · Engineering Leadership
Professional Summary
AI Native Engineer, mobile by specialty. 10+ years shipping consumer mobile and web products end to end. Engineer #3 at Flash. Scaled it from zero to 2M+ downloads (1.6M Android · 400K iOS) and 1.8M MAU in two years. Drove the US market launch. Ships agents & agentic workflows. Builds agentic systems in production and applies AI tooling across design, coding, and delivery, day to day. Deep mobile architecture. Flutter, hybrid WebView / native channels, Shorebird OTA, custom offline image caching. Full-stack breadth. Next.js web platform, Node.js services, Core Web Vitals, production observability with Git-hash crash attribution. Team builder. Grew and mentored cross-functional teams. Set code-review and on-call standards across fintech and consumer products.
Professional Experience
Lead Engineer · Web & Mobile, Flashmonk Pvt. Ltd.
  • •Engineer #3 and primary architect of the Flash mobile app (Flutter) and Next.js web platform. Scaled to 2M+ downloads (1.6M Android, 400K iOS) and 1.8M MAU within two years and drove the US market launch. Owned GetX state management, modular architecture, and a Shorebird OTA pipeline enabling same-day hotfixes without store review.
    • 07/2022 – Present
  • •Designed a custom Flutter image-caching layer (offline DB + TTL) after off-the-shelf libraries fell short for an image-heavy shopping product, significantly improving image load performance on low-end Android devices and flaky networks.
  • •Engineered hybrid WebView performance: pre-warmed WebView instances at app launch to eliminate 600ms–2s white-screen delays on interaction, and shipped a native Swift implementation for iOS-specific WebView flows to overcome jank.
  • •Reduced mobile cold-start time ~45% (1.6s → 900ms) by deferring non-critical startup work; cut SSR page LCP from 8s → 1.8s at p75 (30s → 6s at p90) by resolving API-layer bottlenecks and adding caching, moving typical users into the “good” Core Web Vitals range.
  • •Built production observability (Firebase Crashlytics, Last9) with Git-hash crash attribution tracing non-fatal errors to the exact commit; led web infra migration from AWS Amplify to ECS to control costs at scale.
  • •Integrated LangChain / LangGraph workflows into the product, established a Widgetbook library and analytics & experimentation pipelines (Mixpanel, MoEngage, PostHog, GA), and grew and mentored a cross-functional team setting code-review and on-call standards.

    • Tech: Flutter, Dart, Next.js, TypeScript, Node.js, Swift, AWS, Firebase, LangChain / LangGraph

    Senior Engineer · Credit Platform, Oyster Financial Inc. (via AIML Pvt. Ltd.)

    Owned frontend architecture for the React Native mobile app and web apps of a fintech credit platform; partnered with compliance and backend teams on secure, regulation-aligned experiences, improving onboarding conversion by reducing friction and resolving performance bottlenecks.

    06/2020 – 07/2022
    Product Engineer · Mobile, AlMusbah Group (via ToppersEdge)

    Built and launched Android and iOS apps end-to-end, integrating marketing and engagement tooling (including WebEngage) to drive retention and lifecycle messaging.

    04/2018 – 05/2020
    Software Engineer · Payments Microservices, Creo (Acquired by Hike)

    Contributed to payments microservices, ensuring scalability and reliability of transaction flows.

    11/2017 – 04/2018
    Sr Application Developer (React Native), uCertify

    Led development of e-learning mobile apps on Android and iOS from scratch, building an offline first sync mechanism enabling users to take tests offline and reliably reconcile results on reconnection.

    09/2015 – 11/2017
    Education
    Master of Computer Applications (MCA), Integral University, Lucknow

    76.5%

    06/2018
    Core Skills
    AI & LLM

    LangChain, LangGraph, LLM-powered product workflows, AI-assisted & agentic development, prompt design

    Mobile, Release & Reliability

    GetX, modular architecture, custom image-caching layer, Widgetbook, hybrid WebView / JS bridge / native channels, Shorebird OTA, Git-hash crash attribution, Firebase Crashlytics, Last9, CI/CD

    Backend, Cloud & Data

    Node.js, MongoDB, REST APIs, offline-first sync, payments microservices, AWS (ECS, Amplify, S3), Cloudflare, Firebase, Vercel

    Languages & Frameworks

    Flutter, Dart, React Native, ReactJS, Next.js, Node.js, TypeScript, JavaScript, Swift (native iOS interop)

    Web Performance

    Core Web Vitals (INP / LCP / FCP) optimization, SSR / ISR with Next.js, bundle / chunk strategy, CDN and edge caching

    Analytics & Leadership

    Mixpanel, MoEngage, PostHog, WebEngage, GA, Firebase A/B Testing; team building & mentoring, engineering strategy, delivery management, cross-functional collaboration

    LEADERSHIP & COMMUNITY

    Hosted internal tech talks on mobile performance and scalable Flutter architecture; mentored junior engineers and authored architectural decision records (ADRs) on Flutter architecture and experimentation patterns.