
Md. Mehedi Hasan
Verified Expert in Engineering
Senior Full-stack Developer
Dhaka, Dhaka Division, Bangladesh
Toptal member since April 1, 2020
Mehedi is a full-stack developer with 13+ years of overall web development experience, starting as a WordPress developer and specializing in the PERN stack since 2019. Skilled in PostgreSQL, Node.js, Express.js, React, Next.js, WordPress theme/plugin development, API architecture, Docker, CI/CD, and cloud infrastructure. Experienced in building scalable SaaS apps, complex web platforms, and production-ready solutions.
Portfolio
Experience
- API Integration - 12 years
- Full-stack - 7 years
- Node.js - 7 years
- Next.js - 5 years
- Online Payments - 5 years
- TypeScript - 5 years
- Artificial Intelligence (AI) - 2 years
- DevOps - 2 years
Preferred Environment
REST APIs, Node.js
The most amazing...
...work I’ve done is building scalable SaaS apps, advanced WordPress plugins, APIs, and AI-powered RAG solutions.
Work Experience
Full-stack Developer
Invizo LLC
- Led full-stack development at Invizo, building 10+ scalable SaaS applications using PostgreSQL, Node.js, Express.js, React, Next.js, TypeScript, Docker, GitHub Actions, and AWS.
- Built InvizoCRM, a CRM and affiliate management system for app authors, enabling customer management, affiliate tracking, campaigns, subscriptions, onboarding, logs, and admin workflows.
- Developed Shopify apps, SaaS products, and WooCommerce plugins that automated business workflows and supported production-ready eCommerce operations.
- Architected REST APIs connecting front-end, back-end, payment, eCommerce, and automation systems for scalable SaaS platforms.
- Automated internal systems and workflows, saving management more than 100 hours of manual operational work.
WooCommerce Developer
The Cardus Institute - Main
- Updated custom plugin functionality to make it compatible with WooCommerce subscriptions.
- Managed and fixed bugs through GitHub. Deployed the functionality to Wpengin.
- Oversaw plugin launch process, ensuring stable deployment and zero post-release critical issues.
Senior PHP and WordPress Developer
Howirollsports
- Fixed a hacked WordPress site (Howirollsports) by scanning and cleaning malware across database tables, cache, themes, and plugins.
- Identified and patched security vulnerabilities in outdated code and configurations, ensuring long-term protection.
- Oversaw the recovery and relaunch, restoring full site performance and client trust with zero downtime.
WordPress Gutenberg Block Developer (via Toptal)
Shop Tutors, Inc.
- Developed 20+ dynamic blocks from Figma for lendedu.com. Fixed 200+ bugs and improved legacy blocks. Wrote e2e tests with Cypress and Playwright.
- Managed projects using Jira and GitHub Issues. Communicated through Slack.
- Oversaw the launch of 20+ new blocks for lendedu.com, fixing all the past issues and increasing the editing and publishing efficiency by 40%.
WordPress Developer (via Toptal)
The Cardus Institute - Main
- Developed a custom payment gateway and fixed the existing bug with their site.
- Tracked the bug using GitHub Issues and maintained communication via Slack.
- Contributed to the development of a new payment gateway, after which they could sell in different countries, increasing their sell-up to 50%.
WordPress/WooCommerce Developer
Cardus
- Developed two add-ons for WooCommerce Memberships and Subscriptions and helped with Salesforce integration.
- Managed our project via GitHub and used Slack for day-to-day communication.
- Launched my plugins, selling hundreds of subscriptions.
PHP / WooCommerce Developer
Mood Product Group LLC
- Expedited the WooCommerce site using the new WooCommerce High-Performance Order Storage (HPOS).
- Tracked the tasks through ClickUp and version-controlled them using Git and GitHub.
- Contributed to the new order migration by successfully speeding up a big site with 50,000 members and a large database.
WordPress Developer
The Cardus Institute - Main
- Developed two add-ons. One for a WooCommerce subscription and another for WooCommerce membership.
- Tracked and fixed bugs using GitHub Issues and established day-to-day communication with Slack.
- Added the two plugins into production, and they soon got a few subscription gifting and team membership orders.
WordPress/WooCommerce Developer
The Cardus Institute - Main
- Developed a plugin for WooCommerce membership for the team.
- Tracked the project in GitHub and reported issues in GitHub.
- Contributed to this big magazine company with thousands of visitors: many universities are its clients, purchasing and sharing the membership with students.
WordPress/WooCommerce Developer
Cardus
- Developed a custom payment gateway plugin for Helcim and WooCommerce. It was a conditional payment gateway based on the region.
- Contributed to the project that was managed through ClickUp; team communication was conducted through Slack.
- Served as a WordPress and WooCommerce developer for a company founded in 1974 with a huge audience.
Senior Full-stack Developer
Handprint
- Developed a custom job application where candidates can share their interests, skills, experience, preferences, and education.
- Managed the project and used ClickUp, as well as Git to manage version control.
- Uploaded files to the server using Filezilla. Also used the WP engine to host the site.
WordPress Developer │QA Engineer
Elegant Themes
- Reviewed third-party themes and plugins that are submitted in the Elegant marketplace.
- Fixed core issues reported in GitHub and then, having fixed the issues, created a pull request.
- Created a custom addon and a child theme for Divi.
WordPress Back-end Developer
Kneebouncers
- Developed a game module for kids where the children can learn the alphabet via a fun activity. There are many features. Free users can access and play free games with advertisements throughout the game.
- Developed functionality with themes for children, using Filezilla to push the code to the server.
- Attracted many users to this live game module, contributing to rising active subscriptions.
Founder and Lead WordPress | WooCommerce Developer
Code4webs
- Led the team that developed and contributed to more than 1,500 jobs.
- Tracked and fixed bugs through the FTP and cPanel.
- Utilized the WordPress admin dashboard to track and resolve bugs.
WordPress and WooCommerce Expert
animalchiropracticeducation.com
- Developed an online learning management system where students could easily enroll in the course; it was the best online animal chiropractor school.
- Fixed bugs that were listed in the log file of the WordPress/WooCommerce website.
- Received a certificate of completion after completing the course.
Experience
Zoyokids Headless eCommerce Store Using Next.Js
https://zoyokids.comAs the lead front-end engineer, I built the application using Next.js 16 (App Router), React 19, and Tailwind CSS. I successfully connected the storefront to a headless WordPress and WooCommerce back end using a hybrid data layer of REST APIs and GraphQL. My role involved implementing a fully responsive, kid-friendly design utilizing Swiper.js for product carousels and Shadcn layout primitives.
KEY CONTRIBUTIONS
• Built a robust data layer bridging WordPress posts and pages with WooCommerce product catalogs, carts, and checkout APIs.
• Resolved variation matching bugs to ensure seamless real-time product pricing, image changes, and cart addition for variable products.
• Handled checkout configuration and integrated cash on delivery (COD) payment rules.
• Set up advanced SEO metadata, static Open Graph and Twitter sharing configurations, and integrated Google Analytics along with Meta (Facebook) Pixel for route transition tracking.
AI Agent & RAG Platform with LangChain
https://github.com/code-with-mehedi/InvizoGPT-RAGInvizoCRM
https://invizocrm.comTable Tennis Academy Management System
https://mtta.com.bdInvizo MCP Server
https://mcp.invizo.ioRAG | Chat with PDF
https://github.com/code-with-mehedi/chat-pdf-ragFEATURES
• PDF Upload – Upload any PDF document.
• AI Chat – Ask questions about your uploaded documents.
• Semantic Search – Find relevant content using vector embeddings.
• Real-time Processing – Background job processing with BullMQ.
• Modern UI – Clean, responsive chat interface
RAG | YouTube Summarizer
https://github.com/code-with-mehedi/TalkTube-RAGFEATURES
• Load any YouTube video – Paste a URL or pick a sample (TED Talk, Tech Review).
• Generate Summary – Get a concise summary of the video.
• View Transcript – See the cleaned transcript.
• Chat – Ask anything about the video; answers are based on semantic search over the transcript.
AI Chatbot
RedX Delivery - Shopify APP
https://apps.shopify.com/redx-deliveryRedx for WooCommerce
https://wordpress.org/plugins/redx-for-woocommerce/Designed for eCommerce stores using Redx in Bangladesh, this plugin ensures efficient shipment tracking and enhanced customer satisfaction.
Lendedu
https://lendedu.com/Comment.org
https://comment.org/Doublesdesign.com
https://www.doublesdesign.com/StoreGrowth - WooCommerce Sales Booster Plugin
https://wordpress.org/plugins/storegrowth-sales-booster/Animal Chiropractic Education
https://www.animalchiropracticeducation.com/Table Tennis Management System
Senior WordPress/WooCommerce Developer
Education
Bachelor of Science Degree in Computer Science
Bangladesh University of Business and Technology - Dhaka, Bangladesh
Diploma in Telecommunication Engineering
Jessore Polytechnic Institute - Jessore, Bangladesh
Skills
Libraries/APIs
WordPress API, WooCommerce API, REST APIs, Node.js, React, Playwright, API Development, jQuery, Stripe, Facebook API, SendGrid API, Twilio API, WordPress REST API
Tools
Advanced Custom Fields (ACF), Gutenberg Editor, Composer, NPM, Claude Code, Codex, GitHub, Claude, ChatGPT, NGINX, LearnPress, Mailchimp, Webpack, Figma, Google Analytics, Prisma, Git
Languages
JavaScript, CSS3, Sass, TypeScript, Python, CSS, HTML, HTML5, SQL, ECMAScript (ES6), Coolify, GraphQL
Frameworks
Divi, Next.js, Express.js, LangGraph, Tailwind CSS, Cypress, Vanilla JS, Bedrock
Paradigms
Object-oriented Programming (OOP), Responsive, Responsive Web Design (RWD), Search Engine Optimization (SEO), DevOps, Database Design
Platforms
WooCommerce, Docker, Vercel, Shopify, Amazon Web Services (AWS)
Storage
MySQL, PostgreSQL, Databases, SQLite, JSON, Redis
Other
WooCommerce Subscriptions 2, Ajax, WordPress Plugins, Plugins, Themes, Site Speed Optimization, Website Migration, WordPress Design, eCommerce, APIs, Troubleshooting, Full-stack, API Integration, Back-end, CI/CD Pipelines, Online Payments, Cold Emailing, GitHub Actions, Gemini, Cloudflare, PWA, Lovable, AI Tools, Agentic AI, Agentic RAG Systems, Large Language Models (LLMs), LangChain, Product Owner, RAG Architecture, Retrieval-augmented Generation (RAG), Artificial Intelligence (AI), AI Integration, Security, Scripting, PDF, AI Automation, AI Agents, Supabase, Multi-agent Systems, User Interface (UI), User Flows, User Experience (UX), Workflows, API Design, Architecture, Command-line Interface (CLI), Analytics, Webhooks, Full-stack Development, CRM, MVP Design, Minimum Viable Product (MVP), Emailers, IT Audits, Dashboards, RAG Systems, Software Architecture, Data Modeling, Workflow Automation, Agentic AI Systems, Agentic Workflow Design, Prompt Engineering, Data Structures, Containerization, Generative Artificial Intelligence (GenAI), Code Review, VPS, Payment APIs, Front-end, Front-end Development, Design, Learning Management Systems (LMS), FastAPI, Fintech, Finance, Plugin Development, Computer Science, NextAuth.js, Multi-tenant SaaS, Email Automation, Campaign Management, Affiliate Tracking, Paddle Subscription Billing, Authentication, Admin Dashboard Development, Accounting Module Development, Student and Member Management, ELO Rating System, Full-stack Web Development, JWT Authentication, API Key Management, OpenAI, Qdrant, Deepgram API, React 19, Meta (Facebook) Pixel, Swiper.js
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