Hire the Best Authorize.Net Development Specialists in Karachi, PK

✅ Chargeback and Dispute Specialist I am an experienced chargeback and dispute resolution specialist with over 5 years of experience working with various merchants, including Stripe, EMS, Maverick, Zen Payments, Pay Arc, Elite Payment, PayPal, and Square. I have extensive knowledge in maintaining merchant accounts, responding to chargeback cases. I can definitely assist you with billing, chargebacks, refunds, merchant management, customer service and invoicing. With a strong background in managing and resolving chargebacks, along with a deep understanding of dispute resolution procedures, I am confident in my ability to effectively contribute to your team and help ensure the resolution of disputes in a timely and favorable manner. I would like to be a part of your team as I am capable of providing billing services, customer service and handling disputes. ✅ Industries I have worked with as a Dispute Specialist: ⚫ IT Services and IT Consulting ⚫ Logo Designing, Website Development, E-book Writing, Mobile Application Development, Video Animation ⚫ E-commerce ⚫ Online Coaching Academies ⚫ Side Hustle Academies ⚫ Shopify ⚫ AI Industry ⚫ Saas Industry ⚫ Subscription based Industry ✅ I am capable of performing following tasks with 100% accuracy: ⚫ Fighting chargeback cases ⚫ Maintaining merchant health ⚫ Maintaining Stats (revenue, chargebacks, refunds) ⚫ Maintaining P&L ⚫ Maintaining invoicing sheets ⚫ Looking after alert system (Chargeblast, Ethoca, Verifione Inc) ⚫ Coordinating with customers (emails, texts, discord and call) ⚫ Quality Assurance ⚫ Retention ⚫ Controlling chargebacks and refunds ratio If you still have questions feel free to connect. Thank you.

📞 EVERY MISSED CALL IS A LOST CUSTOMER Most businesses miss calls after hours, during busy periods, or while their staff are focused on the job. I build 24/7 AI voice agents and receptionists that: ✅ Answer calls instantly ✅ Qualify leads ✅ Book appointments ✅ Update your CRM and calendar ✅ Make sure no opportunity slips through These are production-grade systems built with real telephony, low latency, proper monitoring, and reliable failure handling—not demos that break on the first edge case. Voice AI is often where I deliver the fastest return on investment, but it is built on the same foundation I bring to every AI project: • RAG systems that answer from your data instead of guessing • Custom LLM applications and AI agents • Agentic and tool-calling workflows • n8n and Python automation • Integrations between your CRM, calendar, APIs, and internal tools I also work as an AI architect and fractional CTO. Clients often bring me in to rescue AI systems that a previous developer left slow, unreliable, difficult to maintain, or quietly burning through the monthly token budget. ⭐ TOP RATED PLUS ON UPWORK • 100% Job Success Score • $300K+ earned • 200+ completed projects • 7,600+ hours worked 🛠️ WHAT I BUILD ◆ AI Voice Agents & Receptionists 24/7 inbound and outbound voice agents using VAPI or Retell. They can answer calls, qualify leads, book appointments, follow up with prospects, and connect with your CRM, calendar, and telephony systems. ◆ Custom LLM Applications & AI Agents RAG-backed applications, agentic workflows, tool-calling systems, and multi-step AI processes built with OpenAI, Anthropic, and open-source models. I use LangChain and clean, maintainable architecture where it makes sense—not unnecessary complexity. ◆ Retrieval-Augmented Generation RAG done properly, including: • Document processing and chunking • Embedding strategy • Vector database selection • Retrieval and reranking • Source-grounded responses • Evaluation and accuracy improvements The goal is simple: help the model answer from your data instead of guessing. ◆ AI Automation & Workflow Systems I build n8n workflows, Python services, API integrations, and automation systems that connect your tools and eliminate repetitive manual work. ◆ AI Infrastructure Audits & Cleanup Is your existing AI system slow, unreliable, expensive, or difficult to maintain? I can diagnose the root cause and provide a clear, developer-ready roadmap. I can also handle the refactor and implementation. ◆ Full-Stack & SaaS Product Development End-to-end product development, from planning and architecture to deployment and ongoing improvements. When speed to market matters, I can also build rapid no-code or low-code MVPs as a Certified Bubble Developer. 🤝 HOW I WORK I write clean, documented, and maintainable code—not throwaway scripts. I think beyond the happy path and consider: • Latency • Cost • Security • Scalability • Reliability • Failure handling • Long-term maintainability I communicate clearly, provide honest timelines, and flag risks before they become expensive problems. Most clients continue working with me after the first contract because I operate like an engineering partner—not a ticket-taker. ⚙️ TECHNOLOGY STACK VAPI · Retell · Python · FastAPI · Node.js · LangChain · OpenAI APIs · Anthropic APIs · Pinecone · pgvector · Chroma · n8n · React · React Native · Bubble · PostgreSQL 📩 LET’S TALK If you are losing leads because of missed calls, building an ambitious AI product, or trying to repair an AI system that has gone sideways, send me a message or book a consultation. Tell me where your system is today and where you want it to go. I’ll give you an honest assessment of whether—and how—I can help.

Hi! I’m a skilled Full Stack Developer with 9+ years of experience crafting high-performing web applications using ASP.NET, .NET Core, React.js, and Node.js. From building fast, secure backends to sleek, modern UIs I turn complex business needs into real-world software solutions that scale. Whether you're a startup founder or an enterprise looking to modernize, I bring both the technical firepower and the business mindset to drive results. ⚡ What I Bring to the Table: - ASP.NET / .NET Core Development: Clean, maintainable, scalable architecture. - React.js Frontend: Modern, mobile-responsive UI/UX that users love. - Node.js Backend & APIs: Real-time data, third-party integrations, and fast execution. - Database Expertise: SQL Server, MongoDB, PostgreSQL fully optimized for performance. - DevOps & CI/CD: GitHub Actions, Docker, Azure/AWS deployments made seamless. 💬 Why Clients Love Working With Me: ✔️ Proactive communication & quick problem-solving ✔️ Clean code & well-documented deliverables ✔️ Fast turnarounds with no compromise on quality ✔️ 100% focus on long-term value not just code delivery Whether you're starting from scratch, rebuilding a legacy system, or scaling an MVP, I’m here to transform your ideas into robust, reliable, and future-ready software. 📩 Let’s chat and build something amazing together!

𝙇𝙚𝙩 𝙢𝙚 𝙩𝙚𝙡𝙡 𝙮𝙤𝙪 𝙬𝙝𝙮 𝙛𝙤𝙪𝙣𝙙𝙚𝙧𝙨 𝙖𝙣𝙙 𝙩𝙚𝙖𝙢𝙨 𝙗𝙧𝙞𝙣𝙜 𝙢𝙚 𝙞𝙣 𝙬𝙝𝙚𝙣 𝙩𝙝𝙚𝙮’𝙧𝙚 𝙗𝙪𝙞𝙡𝙙𝙞𝙣𝙜 𝙎𝙖𝙖𝙎 𝙖𝙣𝙙 𝙈𝙑𝙋𝙨. 🏆 100% Job Success Score ⭐ 1 % Top Rated Plus Freelancer on UPWORK ✅ 15+ Years of Production Experience as a Senior Full Stack Developer ✅ End-to-End Product Ownership & 100+ Websites Delivered As a Senior Full Stack Developer, I’m usually brought in for MVP builds, product rebuilds, and “this is breaking in production” moments. That’s the difference between hiring a Senior Full Stack Developer and hiring someone who only ships features. 𝐖𝐡𝐚𝐭 𝐈 𝐁𝐮𝐢𝐥𝐝 𝐟𝐨𝐫 𝐘𝐨𝐮 𝐀𝐬 𝐚 𝐅𝐮𝐥𝐥 𝐒𝐭𝐚𝐜𝐤 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐫: 𝟏. 𝐒𝐚𝐚𝐒 𝐏𝐥𝐚𝐭𝐟𝐨𝐫𝐦𝐬 & 𝐂𝐮𝐬𝐭𝐨𝐦 𝐂𝐌𝐒 Multi-tenant architecture, PHP & MySQL based custom CMS, custom admin panels, advanced user dashboards, role-based access, and dynamic data charts development. 𝟐. 𝐞𝐂𝐨𝐦𝐦𝐞𝐫𝐜𝐞 𝐒𝐲𝐬𝐭𝐞𝐦𝐬 As a Full Stack Developer, I build custom storefronts, WordPress plugins, WooCommerce plugins, and Shopify setups optimized for conversions and performance. 𝟑. 𝐌𝐜𝐥𝐚𝐬𝐬 𝐕𝐏𝐬 𝐅𝐚𝐬𝐭 Got an idea? I'm a Full Stack Developer who owns the entire stack. I leverage robust frameworks like Laravel, CodeIgniter, and CakePHP to take you from wireframe to deployed product in weeks, not months. 𝟒. 𝐀𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 𝐖𝐞𝐛 𝐀𝐩𝐩𝐥𝐢𝐜𝐚𝐭𝐢𝐨𝐧𝐬 As a Full Stack Developer working with modern AI tooling, I build advanced AI integrations including ChatGPT and ClaudeAI directly into your product workflows. 𝟓. 𝐀𝐏𝐈 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 & 𝐓𝐡𝐢𝐫𝐝-𝐏𝐚𝐫𝐭𝐲 𝐈𝐧𝐭𝐞𝐠𝐫𝐚𝐭𝐢𝐨𝐧𝐬 Expert implementation of RESTful architectures and complex third-party systems. I connect everything seamlessly, from secure payment checkouts to enterprise automations. 𝟔. 𝐋𝐞𝐠𝐚𝐜𝐲 𝐒𝐲𝐬𝐭𝐞𝐦 𝐌𝐨𝐝𝐞𝐫𝐧𝐢𝐳𝐚𝐭𝐢𝐨𝐧 Slow, outdated codebase? As a Full Stack Developer, I clean up technical debt and migrate legacy monoliths to scalable structures without breaking live systems. 𝐒𝐞𝐫𝐯𝐢𝐜𝐞𝐬 & 𝐓𝐡𝐢𝐫𝐝-𝐏𝐚𝐫𝐭𝐲 𝐀𝐏𝐈 𝐄𝐱𝐩𝐞𝐫𝐭𝐢𝐬𝐞: ✔ Payments & Billing: Stripe, PayPal, CCAvenue, Authorize.net, MangoPay ✔ Communications & Video: Twilio, Twilio Video Conferencing, Zoom, Jitsi ✔ Marketing & CRM Automation: HubSpot, ConnectWise, MailChimp, SendGrid ✔ Data, Location & Surveys: Qualtrics, TextLocal, ID Analyzer, UPS, Google Maps, Google GeoLocation ✔ Security & Monitoring: JWT, Auth0, Google ReCaptcha, Sentry 𝐓𝐞𝐜𝐡 𝐒𝐭𝐚𝐜𝐤: ➤ 𝐅𝐫𝐨𝐧𝐭𝐞𝐧𝐝 → ReactJS, VueJS, JavaScript, jQuery, Bootstrap, HTML5/CSS3 ➤ 𝐁𝐚𝐜𝐤𝐞𝐧𝐝 → PHP (Laravel, CodeIgniter, CakePHP), NodeJS, Custom MVC ➤ 𝐃𝐚𝐭𝐚𝐛𝐚𝐬𝐞 → MySQL, 𝐀𝐈-𝐏𝐨𝐰𝐞𝐫𝐞𝐝 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐦𝐞𝐧𝐭 𝐓𝐨𝐨𝐥𝐬: ➤ Cursor, Cline, GitHub Copilot, Claude Code ➤ ChatGPT, Gemini, v0.dev, Bolt.new ➤ n8n, Zapier, Make (Integromat) ➤ AI Agent Integrations & Workflow Automation 𝐖𝐡𝐲 𝐂𝐥𝐢𝐞𝐧𝐭𝐬 𝐜𝐜𝐜𝐡𝐨𝐨𝐬𝐞 𝐭𝐨 𝐇𝐢𝐫𝐞 𝐌𝐞..? ✅ 𝐅𝐮𝐥𝐥 𝐎𝐰𝐧𝐞𝐫𝐬𝐡𝐢𝐩 - I handle frontend, backend, database, and cloud ✅ 𝐒𝐡𝐢𝐩𝐬 𝐅𝐚𝙨𝐭 - 100+ successful website launches on aggressive timelines ✅ 𝐒𝐜𝐚𝐥𝐞𝐬 𝐖𝐞𝐥𝐥 - Architecture designed for growth and heavy traffic from day one ✅ 𝐂𝐥𝐞𝐚𝐫 𝐂𝐨𝐦𝐦𝐮𝐧𝐢𝐜𝐚𝐭𝐢𝐨𝐧 - Plain English updates, no tech jargon ✅ 𝐒𝐭𝐚𝐲𝐬 𝐀𝐟𝐭𝐞𝐫 𝐋𝐚𝐮𝐧𝐜𝐡 - Available for long-term relationships built on trust and loyalty ✅ 𝐓𝐡𝐢𝐧𝒌𝙨 𝐋𝐢𝗸𝐞 𝐚 𝐅𝐨𝐮𝐧𝐝𝐞𝐫 - I treat your product as a business, not a ticket Please check my UpWork profile, and read other clients' feedback and comments about me. 𝐀𝐕𝐀𝐈𝐋𝐀𝐁𝐋𝐄 𝐅𝐎𝐑 𝐋𝐎𝐍𝐆 𝐓𝐄𝐑𝐌 𝐑𝐄𝐋𝐀𝐓𝐈𝐎𝐍𝐒𝐇𝐈𝐏 𝐖𝐈𝐓𝐇 𝐓𝐑𝐔𝐒𝐓 𝐀𝐍𝐃 𝐋𝐎𝐘𝐀𝐋𝐓𝐘.. Full Stack Developer | PHP Developer | Laravel Developer | CodeIgniter Developer | CakePHP Developer | Senior Web Developer | WordPress Developer | | WooCommerce Developer | Shopify Developer | ReactJS Developer | VueJS Developer | NodeJS Developer | AI Integration Specialist | API Integration Expert | Custom CMS Developer | SaaS Developer | MVP Developer | Backend Developer | Web Application Developer | Frontend Developer | Database Developer | MySQL Expert | Stripe Integration Developer | PayPal Integration Expert | Twilio Developer | AWS Developer | Full Stack Engineer | Senior PHP Developer | PHP Laravel Developer

Senior Full Stack Architect | .NET 8 & Next.js | SaaS, AI & Stripe Billing Architecting enterprise-grade, high-performance web applications and SaaS platforms. With over 7 years of full-stack engineering experience, I specialize in migrating legacy systems to modern frameworks and building secure, multi-currency architectures. HOW I DELIVER VALUE (PROVEN DEPLOYMENTS) I do not just write code; I design scalable systems. I strictly enforce the separation of business logic from the presentation layer to ensure long-term maintainability. ▪ Global B2B eCommerce & Analytics Architected a custom CMS and pricing engine supporting 27 languages. Enabled dynamic multi-currency conversions and global routing using .NET Core and Next.js. ▪ Enterprise Automation & Regression Testing Engineered a comprehensive automation testing solution, migrating legacy QA tools to .NET 8. Integrated physical device testing pipelines using HeadSpin and Selenium to drastically reduce deployment cycles. ▪ AI Proxy & Trade Quoting Architecture Developed the backend infrastructure for an AI-driven contractor application. Integrated Supabase, Twilio, and complex Stripe Connect payment gateways for seamless multi-party transactions. ▪ Social Intelligence & Observability Dashboards Built scalable review aggregation platforms integrating custom data scraping. Implemented OpenTelemetry instrumentation for deep backend monitoring, distributed tracing, and metric sampling. CORE TECHNICAL SCHEMA ► Enterprise Backend: .NET 8, C#, ASP.NET Web API, RESTful Architecture ► High-Performance Frontend: React, Next.js (App Router), TypeScript, WCAG Accessibility ► Cloud & Infrastructure: Azure App Services, Azure DevOps, CI/CD pipelines, Docker, opentelemetry/Otel, Datadog, Signoz ► Databases: SQL Server (Performance Tuning, Stored Procedures), EF Core ► AI & Integrations: Local AI Model Orchestration (DeepSeek, Qwen), Stripe Webhooks, OAuth2 If your project requires robust full-stack architecture built for scale, click "Invite to Job" to discuss your roadmap.

I am a Senior .NET Developer with over 10 years of experience building high-quality eCommerce stores, scalable web applications, custom APIs, and cloud-based business systems. My main expertise is in nopCommerce and the Microsoft .NET stack. I work with ASP.NET Core, MVC, C#, Web API, SQL Server, Entity Framework, Vue.js, Angular, React, Azure, AWS, Docker, and modern application architecture. I have strong hands-on experience with nopCommerce customization, custom plugin development, theme customization, checkout changes, payment and shipping integrations, ERP/CRM integrations, performance optimization, version upgrades, and long-term store maintenance. I can help with: - nopCommerce custom plugin development - nopCommerce theme and UI customization - Payment gateway and shipping integration - ERP, CRM, and third-party API integration - ASP.NET Core and C# web application development - REST API development and integration - SQL Server optimization and database fixes - Vue.js, Angular, and React frontend work - Azure, AWS, Docker, and cloud deployment - Performance tuning, bug fixing, and code refactoring - Long-term support and maintenance I focus on clean code, clear communication, fast delivery, and long-term client success. Whether you need a nopCommerce expert, a full-stack .NET developer, or help with cloud-based business applications, I can deliver reliable and scalable solutions.