Shahzaib

Senior Software Engineer

Fiverr • Freelance

Jan 2022 - Present • 4 yrs 9 mos

Professional Experience • Operate as an independent contractor, delivering enterprise-grade web applications, custom SaaS products, and workflow automation systems for global founders and businesses across the US, UK, Canada, and Europe. Core Technical Responsibilities • Full-Lifecycle Ownership: Lead end-to-end software development lifecycles, including architecture design, technical documentation, frontend/backend engineering, database indexing, and cloud deployment. • Frontend Engineering: Develop high-performance frontend interfaces using Next.js (App Router), React, TypeScript, and Tailwind CSS with strict attention to Core Web Vitals and responsiveness. • Backend Architecture: Engineer resilient backend architectures, microservices, and RESTful APIs using PHP (Laravel), Node.js (Express), and Python. • Database Optimization: Design, optimize, and secure relational and NoSQL databases utilizing PostgreSQL, MySQL, and Redis for caching and session management. • AI & Automation: Build autonomous business automation and AI workflows utilizing self-hosted n8n, OpenAI/Claude LLM APIs, and third-party webhook integrations. Key Achievements & Delivery Record • Project Delivery: Successfully architected and deployed 50+ custom web applications, SaaS MVPs, and internal CRM/ERP dashboards with a 100% on-time delivery record. • Monetization & Billing: Integrated multi-tenant subscription infrastructure with Stripe Billing, webhooks, and automated recurring invoice management. • Performance Engineering: Achieved sub-second page loads and optimized API execution speeds by implementing database query caching, Redis pipelines, and edge CDN distribution. • Client Handover: Provided comprehensive technical handover, ensuring zero vendor lock-in and 30 days of dedicated post-launch support across all client engagements.

Associate Software Engineer

Developers Studio • Tiempo completo

Jan 2024 - Jun 2026 • 2 yrs 5 mos

Professional Experience • Engineered and shipped scalable full-stack web applications, custom SaaS architectures, and automated workflow pipelines for global commercial clients. Key Responsibilities & Architectural Scope • Frontend Architecture: Architected high-performance web applications and dynamic client portals using Next.js (App Router), React, TypeScript, and Tailwind CSS. • Backend Development: Developed secure, modular backend services and REST/GraphQL APIs utilizing PHP (Laravel) and Node.js (Express) with clean OOP design principles. • Database & Caching: Designed relational and distributed database schemas utilizing PostgreSQL, MySQL, and Redis caching—consistently achieving sub-second API response times under high concurrency. • Automation & AI: Built end-to-end automation pipelines and AI agents using self-hosted n8n, connecting third-party services including Stripe Billing, OpenAI/Claude APIs, and HubSpot CRM. Key Achievements & Business Impact • Production Delivery: Delivered 20+ production web applications and custom modules with 99.9% uptime and zero critical post-deployment defects. • SaaS Optimization: Engineered multi-tenant SaaS subscription billing systems with Stripe webhook validation, reducing payment drop-off rates by 22%. • Workflow Automation: Reduced manual data workflows by 85% across client operations by implementing bespoke n8n webhook automations and asynchronous queue workers. • Performance Engineering: Optimized Core Web Vitals and frontend asset bundles, improving page loading performance from 3.2s to under 0.9s across deployed client platforms.

Web Application Developer

Freelance • Tiempo completo

Feb 2021 - Dec 2023 • 2 yrs 10 mos

Professional Experience • Operated as an independent developer, delivering custom web applications, dynamic database systems, and bespoke e-commerce platforms for international startups and SMEs across the US, UK, Australia, and Europe. Key Responsibilities & Technical Execution • Full-Stack Engineering: Architected and deployed full-stack web solutions using PHP, Laravel, JavaScript, HTML5/CSS3, and Bootstrap/Tailwind CSS. • CMS & E-Commerce Customization: Built custom WordPress and WooCommerce architectures, developing bespoke themes, plugins, and custom post-type systems tailored to client specifications. • Database Management: Designed, normalized, and optimized relational MySQL databases to handle high-volume product catalogs and concurrent user transactions. • API & Payment Integration: Integrated third-party REST APIs, webhooks, and secure payment processing systems including Stripe, PayPal, and Authorize.net. Key Achievements & Milestones • Client Delivery: Successfully delivered 30+ production web applications and commercial platforms with 100% on-time milestone completion and 5-star client feedback. • Performance Optimization: Refactored legacy codebases and optimized slow database queries, improving average page rendering and server response times by over 40%. • SEO & Responsiveness: Implemented technical SEO best practices, schema markups, and cross-browser responsiveness, driving significant organic search visibility for client websites. • Security Hardening: Conducted comprehensive pre-launch security audits, hardening client systems against SQL injections, XSS vulnerabilities, and unauthorized access.