hammadxcm - Overview

🎯 About Me

const hammadKhan = {
    title: "Senior Full Stack Engineer",
    experience: "8+ years building systems at scale",
    location: "Lahore, Pakistan 🇵🇰",
    specialization: "Distributed Systems & Platform Architecture",
    currentRole: "Senior Full Stack Engineer @ NexaQuanta",
    workStyle: "Technical Leadership & Full-stack Development",

    expertise: {
        systemDesign: ["Microservices", "Event-Driven Architecture", "Domain-Driven Design"],
        backend: ["Ruby on Rails", "NestJS", "NodeJS", "GraphQL", "High-Performance APIs"],
        frontend: ["ReactJS", "VueJS", "NextJS", "Progressive Web Apps"],
        infrastructure: ["AWS", "Azure", "Docker", "Redis", "BullMQ", "Kubernetes"],
        databases: ["PostgreSQL", "MongoDB", "MySQL", "Prisma ORM", "Data Modeling"],
        integrations: ["Multi-API Platforms", "CRM Systems", "Payment Gateways", "CitNOW"],
        security: ["OWASP Top 10", "Audit Systems", "Injection Prevention", "HIPAA"]
    },

    technicalLeadership: [
        "Delivered 115+ MRs in 5 months at NexaQuanta",
        "Designed fault-tolerant systems handling millions of requests",
        "Led migration of monolithic apps to microservices architecture",
        "Mentored engineering teams on system design and best practices",
        "Established engineering standards and code review processes"
    ],

    systemsBuilt: [
        "Enterprise appointment lifecycle with cross-module linking (60+ MRs)",
        "Multi-dealer org scoping with dual-database architecture",
        "CSV data import pipelines with batch optimization & duplicate detection",
        "Generic audit module for compliance and forensic traceability",
        "Real-time data processing pipelines with 95% job success rate",
        "Progressive loading systems reducing page load by 70%",
        "Zero-downtime Stripe API migration with 99.9% uptime"
    ],

    openSource: [
        "Rails Core Contributor — merged PR to rails/rails",
        "daemon-os — macOS MCP server for AI agent computer-use",
        "rubocop-hk — 2,800+ downloads on RubyGems",
        "ramadan-cli-pro — TUI dashboard with prayer times & i18n"
    ],

    currentFocus: "Platform Engineering & Technical Strategy",
    openTo: ["Staff/Principal Engineering Roles", "Architecture Consulting", "Team Leadership"],
    philosophy: "Building systems that scale, teams that deliver, and solutions that last 🚀"
};

🛠️ Professional Tech Arsenal

🎯 Core Expertise

🚀 Frontend Development

⚙️ Backend & APIs

🗄️ Databases & Storage

☁️ Cloud & DevOps

🧪 Testing & Quality

🤖 AI & Modern Tools

🔧 Additional Languages & Tools

💻 IDEs & Development Environment

💼 Professional Journey & Achievements

🎯 Current Role

_{Since October 2025 • Remote (London, UK)}

🏢 Professional Experience & System Architecture

🚀 Senior Full Stack Engineer @ NexaQuanta

Full-time • Remote (London, UK)

Full-Stack Development & Platform Engineering:

📊 CRM & Product Reporting System

Challenge: Lack of centralized reporting capability for business intelligence
Solution: Built comprehensive reporting module with email-based delivery supporting CRM and Product analytics
Impact: Enabled self-service reporting for sales and operations teams, improved business visibility into customer interactions and pipeline metrics

🗄️ Enterprise Database Schema Migration

Challenge: Incomplete database schema limiting cross-system data integration
Solution: Designed and executed complete database schema migration achieving 100% parity with source system
Impact: Enabled complete dealer hierarchy tracking, unified data management, established foundation for real-time synchronization and business intelligence

🗓️ Aftersales Appointments Management System

Challenge: No centralized appointment management for aftersales workflows — advisors had no way to create, track, or link appointments across HCI, Payment, and Triage modules
Solution: Built a complete appointment lifecycle module with multi-step creation forms, fly-out detail panels, status tags, advanced filtering/sorting, cross-module linking, and re-assignable "Assigned To" fields backed by SSO user lookup
Impact: Enabled full aftersales workflow management for dealer groups, appointment linking across HCI/Payment/Triage, real-time status tracking, and 60+ merged MRs delivering the feature end-to-end

📹 CitNOW Video Library & Status Integration

Challenge: No visibility into video status (Sales & Workshop) within the dealer portal — advisors had to switch between systems to track video progress
Solution: Built a dedicated video library page with filtering/sorting by status, CitNOW Sales and Workshop integration, NGD URL generation for direct video access, isolated filter state between Aftersales and Sales pages, and mobile-responsive design matching Figma specs
Impact: Unified video management across Sales and Aftersales in a single portal, eliminated context-switching between systems, real-time video status visibility for all advisors

📥 Enterprise Data Import Pipeline (IC5 → IC4)

Challenge: No mechanism to migrate legacy IC5 customer and appointment data into the new portal — manual entry was infeasible at scale
Solution: Built a full CSV-based data import pipeline with upload UI, server-side validation, duplicate detection (email uniqueness enforcement), appointment status mapping, import summary with invalid/valid record breakdown, and performance-optimized batch processing
Impact: Enabled seamless migration of enterprise customer and appointment datasets, prevented duplicate records with global uniqueness enforcement, reduced import processing time significantly with batch optimization

🏢 Multi-Dealer Org Scoping & Dual-Database Architecture

Challenge: Portal lacked proper dealer/org scoping — queries returned data across all organizations without isolation, creating data leakage risk in multi-dealer environments
Solution: Integrated orgId throughout the portal with comprehensive dealer scoping for all IC4/IC5 lookup queries, dual-database querying strategy for cross-system appointment resolution, and dealer hierarchy tracking
Impact: Proper data isolation per dealer organization, eliminated cross-org data leakage, established foundation for scalable multi-tenant dealer group management

🔒 Security Hardening & Generic Audit Module

Challenge: Critical query injection vulnerability identified by Aikido security scan in the presenter service; no audit trail for user actions across the platform
Solution: Patched the injection vulnerability in the presenter microservice; architected and implemented a generic audit module with activity tracking refactor, reusable across all platform entities
Impact: Eliminated critical security vulnerability (CVE-level), established comprehensive audit trail for compliance and forensic traceability across all user actions

⚙️ Redis Cluster & Infrastructure Hardening

Challenge: Redis Cluster CROSSSLOT errors crashing BullMQ job queues; optional auth not handled
Solution: Fixed CROSSSLOT key violations for BullMQ sso-import queue, added graceful Redis authentication handling
Impact: Stable job processing in clustered Redis environments, zero queue failures from infrastructure misconfig

Technologies: Microservices NestJS Node.js React.js Next.js MongoDB PostgreSQL Prisma ORM AWS Amazon EC2 Amazon S3 Redis BullMQ API Development Jest Vitest

🚀 Staff Software Engineer @ TechXMation

Freelance • Lahore, Pakistan

System Design & Architecture Leadership:

🏗️ Distributed Data Processing Architecture

Challenge: Time-consuming manual data exports causing operational bottlenecks
Solution: Designed and implemented event-driven export system with real-time progress tracking
Architecture: Built pub/sub mechanism using Redis streams with job queuing system
Impact: Reduced export wait times from 30+ minutes to under 5 minutes for large datasets

⚡ Progressive Loading System Design

Challenge: Database queries causing 10+ second page load times
Solution: Architected progressive data loading with ReactJS and asynchronous rendering
Technical Approach: Implemented lazy loading with pagination, caching layer using Redis
Impact: Reduced initial page load from 12s to 2.3s, improved user engagement by 70%

🔄 Multi-Level Job Processing Architecture

Challenge: Sidekiq job failures, memory overflow, and deployment interruptions
Solution: Designed complex multi-level batch processing with callback mechanisms
Technical Implementation: Created job monitoring system with retry logic and error handling
Impact: Improved job success rate from 60% to 95%, reduced memory usage by 40%

🌉 Microservices Integration & Data Flow

Challenge: Poor communication between Pretzel and Fawkes systems causing data inconsistency
Solution: Designed service mesh architecture with message queuing and event sourcing
Implementation: Built central data mapping service for YouTube/TikTok data with comprehensive API documentation
Result: Eliminated 90% of data duplicates, improved system reliability

Technologies: Ruby on Rails ReactJS Redis Sidekiq AWS S3 PostgreSQL Microservices Event-Driven Architecture

🔧 Application Developer @ Machine Tools

Full-time • Lahore, Pakistan

Database Architecture & Performance Engineering:

🔍 Search Engine Optimization

Challenge: Slow database queries affecting user experience
Solution: Implemented Sphinx Search with optimized indexing strategy
Technical Approach: Designed full-text search with Arel SQL for complex query optimization
Impact: Improved search response time by 300%, enhanced data retrieval efficiency

📊 Advanced Data Filtering System

Technical Implementation: Built sophisticated filtering mechanism with role-based access control
Architecture: Designed permission system with hierarchical user roles and content visibility
Performance: Optimized SQL queries resulting in 85% faster data filtering

🎛️ Email Delivery System Enhancement

System Design: Architected scalable email delivery system with formatting improvements
Technical Features: Implemented template system with user engagement tracking
Result: Improved email delivery rate by 25% and user engagement metrics

Technologies: Ruby on Rails Sphinx Search Arel SQL PostgreSQL Role-Based Access Control

💻 Senior Software Engineer @ Freelance

Remote • Lahore, Pakistan

Security Architecture & API Design:

🔐 API Security Framework

Challenge: Ensure integrity and authenticity of API communications
Solution: Designed robust API signature verification system
Implementation: Built HMAC-based authentication with JWT tokens and rate limiting
Security Features: Implemented request signing, timestamp validation, and replay attack prevention

🏗️ Component-Based Architecture

Technical Approach: Designed reusable ReactJS components with maintainable architecture
System Design: Created modular component library with proper state management
Impact: Reduced development time by 40% through component reusability

🔄 Multi-Platform API Integration

Architecture: Built unified API integration layer supporting multiple third-party services
Technologies: Designed adapter pattern for seamless API switching and error handling
Result: Streamlined integration process across different platforms

Technologies: Ruby on Rails ReactJS GraphQL API Security Chrome Extensions JWT Authentication

🚀 Software Engineer @ Sendoso

Full-time • Lahore, Pakistan • 4 Years

Enterprise-Scale System Architecture & Platform Engineering:

🏛️ Multi-API Integration Platform

System Design: Architected unified integration platform supporting 10+ APIs (Kolide, Microsoft Azure, Kandji, Render, Secure Frame)
Technical Challenge: Designed fault-tolerant API gateway with circuit breakers and retry mechanisms
Architecture Pattern: Implemented adapter pattern for seamless API integration with centralized error handling
Impact: Reduced integration time from weeks to days for new APIs

💳 Payment System Migration Architecture

Challenge: Migrate from Stripe API v2 to v3 without downtime
Solution: Designed blue-green deployment strategy with feature flags
Technical Implementation: Built backward-compatible payment layer with gradual rollout
Result: Zero-downtime migration with 99.9% uptime during transition

📊 Real-Time Monitoring & Analytics Platform

System Design: Architected comprehensive API logging dashboard with real-time metrics
Technical Stack: Built with Prometheus Ruby client, integrated with New Relic for advanced monitoring
Data Pipeline: Designed log aggregation system handling 1M+ requests/day
Migration: Successfully migrated to New Relic with improved monitoring capabilities

🔄 CRM Integration & Automation Platform

Architecture: Designed event-driven automation system for Salesforce-Sendoso synchronization
Technical Implementation: Built pub/sub messaging system with dead letter queues
Integration Scope: Connected HubSpot, Salesloft, Marketo, and Engagio platforms
Performance: Achieved 60% increase in operational efficiency through automation

🎛️ Admin Platform & Role Management System

System Design: Architected role-based access control with granular permissions
Technical Features: Built hierarchical permission system with audit logging
Security: Implemented secure admin panel with multi-factor authentication
User Management: Designed scalable user role system supporting enterprise clients

🌐 Browser Extension Architecture

Technical Challenge: Build performant Chrome extension for CRM integration
Solution: Designed lightweight extension with background script architecture
Performance: Optimized for minimal memory footprint and fast loading
Integration: Seamless data sync between HubSpot, Salesloft, and Sendoso platforms

📈 Customer Analytics & Retention Platform

Integration: Implemented ChurnZero for customer behavior analysis
Data Pipeline: Built real-time analytics pipeline for customer insights
Actionable Intelligence: Designed alerting system for customer retention teams
Impact: Improved customer retention through data-driven insights

🏗️ Microservices Architecture & Documentation

System Design: Contributed to notification microservice using Domain-Driven Design principles
Architecture: Designed event-sourced notification system with message queuing
Documentation: Created comprehensive API documentation and integration guides
Scalability: Built for high-throughput notification delivery

🌍 Internationalization & Global Scale

Challenge: Enable global expansion with multi-language support
Solution: Designed i18n system for email templates with 20+ languages
Architecture: Built localization pipeline with translation management
Impact: Enabled Sendoso's expansion to international markets

Technologies: Ruby on Rails ReactJS Redux GraphQL Chrome Extensions Salesforce API HubSpot API Marketo API Stripe API New Relic Prometheus ChurnZero Domain-Driven Design Event-Driven Architecture Microservices

⚡ Software Engineer @ Engin Technologies

Full-time • Lahore, Pakistan

Full-Stack Development & E-commerce Architecture:

🛒 E-commerce Platform Architecture

Technical Implementation: Built scalable e-commerce solutions using Spree Commerce framework
System Design: Designed product catalog and order management system
Integration: Connected payment gateways and inventory management systems
Performance: Optimized for high-traffic e-commerce operations

🎯 Frontend Architecture with State Management

Technical Approach: Implemented ReactJS with Redux for complex state management
Architecture: Designed component-based frontend with efficient data flow
Integration: Built seamless frontend-backend communication with Rails & GraphQL
User Experience: Created responsive and interactive user interfaces

Technologies: Ruby on Rails ReactJS ReduxJS GraphQL AngularJS Spree Commerce E-commerce Architecture

🚀 Recent Achievements

🚀 Sidekiq Optimization _{Implemented multi-level batch processing Reduced job failures by 95%}	📊 Progressive Web Apps _{Built async loading pages Reduced load times by 70%}	🔄 CRM Automation _{Automated Salesforce-Sendoso sync Increased efficiency by 60%}
💳 Payment Systems _{Upgraded Stripe API v2 → v3 Zero downtime migration}	🎯 Browser Extensions _{Built CRM integration tools Used by 1000+ sales reps}	☁️ Scalable Storage _{Implemented S3 data solutions Handling TB-scale data}

🌟 Open Source & Community

🛤️ Rails Core Contribution _{Merged PR to rails/rails — Fixed Ruby 4.0 delegator warning in ActiveModel/ActiveRecord}	🌙 ramadan-cli-pro _{Published npm package — TUI dashboard with prayer times, i18n & notifications}	💎 rubocop-hk _{Published RubyGem — 2,800+ downloads Modern RuboCop config for Ruby & Rails}
🔍 image-magnifier _{React zoom component — 8 stars, 748+ downloads TypeScript with 7 releases}	⚡ electric-border-css _{Animated CSS border effects — React, Vue, Next.js & Svelte with live demo}	🖥️ daemon-os _{macOS MCP server for AI agent computer-use — gives AI eyes & hands on your Mac}