Engineering High-Performance Shopify Apps & Custom Storefronts.
Hi, I’m Nazmul Hawlader (NazmulCodes). I build published Shopify App Store applications (React/Polaris/GraphQL/Python) and hand-crafted Online Store 2.0 themes with zero page builder bloat, sub-second load speeds, and deep merchant customizability.
Stockly: Inventory & Reorder
Conceived, architected, and bootstrapped by Nazmul Hawlader. Stockly empowers modern Shopify merchants with sales-velocity demand forecasting, automated supplier purchase orders, and real-time multi-channel staff notifications.
Inventory Optimization
Automated demand intelligence and reordering workflows designed to eliminate stockouts and optimize working capital.
- Sales Velocity Demand Forecasting: Predicts exact stockout runways and safety stock buffers based on 7-day and 30-day velocity.
- 1-Click Purchase Orders (PO): Generates automated supplier purchase orders factoring in vendor lead times and minimum order quantities.
- Multi-Location Stock Transfers: Seamlessly balances inventory between regional warehouses and retail POS locations.
- Dead Stock & Stagnant Inventory Alerts: Identifies slow-moving capital to prevent warehouse overstock holding costs.
Stock & Staff Notifications
Real-time operational alerts for store managers, warehouse teams, and automated back-in-stock recovery for shoppers.
- Real-Time Slack & Email Alerts: Instant notifications to staff channels the exact millisecond inventory breaches safe thresholds.
- Automated Back-in-Stock Customer Alerts: Captures high-intent customer emails on sold-out products and sends restock notifications.
- Auto-Hide Sold-Out Products: Automatically hides out-of-stock items to prevent overselling, and automatically republishes on restock.
- Shopify Flow & Webhook Triggers: Deep integration with Shopify Flow, Klaviyo, and external ERPs for seamless operations.
Published Shopify Apps in Production
Engineered from ground up with React, Shopify Polaris, App Bridge, GraphQL Admin APIs, and high-throughput Python / Node.js backends.
DemandMind
An AI/ML-driven inventory & sales prediction app embedded in Shopify Admin, processing merchant sales history to generate daily/monthly forecast models.
Stockly: Inventory & Reorder
Flagship SaaS founded by Nazmul Hawlader: an all-in-one Shopify inventory optimization and automated reordering platform featuring sales-velocity demand forecasting, multi-location stock transfers, 1-click supplier purchase orders, and real-time staff & back-in-stock alerts.
Shoppable Posts
Published Shopify App that empowers merchants to tag products directly in blog posts and editorial content, allowing instant cart additions without leaving articles.
EUR to BGN
Shopify App providing seamless live currency conversion between Bulgarian Lev (BGN) and Euro (EUR) with dual-price display compliance.
Featured Portfolio & Case Studies
Explore 33+ real-world Shopify embedded apps, bespoke Liquid storefronts, high-converting advertorials, and custom engineering projects.
DemandMind
An AI/ML-driven inventory & sales prediction app embedded in Shopify Admin, processing merchant sales history to generate daily/monthly forecast models.
Stockly: Inventory & Reorder
Flagship SaaS founded by Nazmul Hawlader: an all-in-one Shopify inventory optimization and automated reordering platform featuring sales-velocity demand forecasting, multi-location stock transfers, 1-click supplier purchase orders, and real-time staff & back-in-stock alerts.
Clinique Dentaire Aurea
Rebuilt dental clinic homepage into 11 hand-coded custom Liquid sections + header/footer with 369 theme settings, 0 page builder bloat, and Lighthouse 93 performance.
Shoppable Posts
Published Shopify App that empowers merchants to tag products directly in blog posts and editorial content, allowing instant cart additions without leaving articles.
Gum Health Magazine
Engineered a modular advertorial landing page template system with custom Liquid blocks, schema markup, and zero page builder dependencies for high-volume paid traffic.
LED Neon Flex
Developed a bespoke nested variant product configurator for commercial LED fixtures without monthly third-party app subscriptions, calculating live pricing and custom cuts.
B2B Be Sunset
Built a dedicated B2B wholesale portal with customer-tier verification, minimum order quantity rules, bulk quick-order matrix, and VAT validation.
Klense.nl
Built 3 high-converting landing pages for Dutch DTC brand Klense, featuring an interactive postcode-based water quality diagnostic tool.
EUR to BGN
Shopify App providing seamless live currency conversion between Bulgarian Lev (BGN) and Euro (EUR) with dual-price display compliance.
Reliv Products
Full homepage overhaul for a 35-year nutrition and wellness brand, introducing modern editorial typography, product clinical proof sections, and fluid responsive design.
Hempire Gardens
Diagnosed and resolved a broken Shopify Markets configuration and subfolder routing conflict for a UK CBD brand, restoring organic search equity.
Kind Laundry
Comprehensive site speed overhaul for eco-friendly DTC brand, eliminating legacy jQuery bottlenecks, fixing API refresh loops, and implementing native lazy loading.
Mallet London
Crafted bespoke homepage and collection showcase sections for British luxury footwear brand Mallet, emphasizing editorial imagery and product drops.
Gus* Modern
Collaborated on the custom Shopify theme development for contemporary furniture manufacturer Gus* Modern, supporting fabric swatch selections and retail locator.
Chlorophyll Water
Engineered brand-driven direct-to-consumer store for bottled wellness water, incorporating recurring subscriptions, press carousels, and retail store locator.
Plum Deluxe
Built subscription club onboarding, custom gift set bundling options, and seasonal sample pack selector for artisan tea purveyor.
Myant Health
Built healthcare technology e-commerce portal for biometric monitoring garments with medical device compliance notices and multi-tiered clinical packaging.
Urban Leaf
Full-scale store build for hydroponic gardening company, including custom kit builders, plant recommendation quiz, and wholesale inquiry funnel.
4E's USA
Commercial scientific equipment storefront with technical specification sheets, RFQ (Request for Quote) system, and bulk laboratory distributor discounts.
AHW Studio
Bespoke dark-themed e-commerce experience for Sydney-based handcrafted jewelry and horology studio, focusing on craftsmanship storytelling and custom engraving.
Brightlink AV
Commercial matrix switcher and video wall hardware catalog with interactive wiring diagram guides and system builder.
Broidr
Interactive apparel customization store allowing users to upload vector logos, choose thread colors, and preview embroidered apparel.
FitXR
Modern web portal for leading VR fitness app featuring class schedules, trainer profiles, Oculus/Meta hardware accessory bundles, and membership activation.
Grill Armor Gloves
Complete Shopify storefront overhaul for leading heat-resistant BBQ gear brand, featuring temperature rating comparison tables and bundle discounts.
Unify Patches
Resolved complex merchant account creation workflows, artwork upload validation, and custom patch proof approval pipelines for manufacturing business.
The Idea Space
Bespoke Shopify storefront for creative workspace platform, blending lifestyle merchandise with event ticket booking and membership subscriptions.
GeoRelief
German e-commerce store for 3D raised-relief geographical maps, featuring regional filters, frame configurators, and multi-language support.
Frome
Handcrafted ceramic and textile home goods store with story-rich artisan profiles, gift registry integrations, and warm earth-tone design.
Oush World
Converted a comprehensive 14-page high-fidelity prototype into a production-ready Shopify theme with subscription toggles and custom cart drawer.
Hasenbos Militaria
Configured specialized domestic (PostNL) and international shipping profiles with three tiers of custom high-value insurance and full Dutch localization.
The Cosy
Developed cozy lifestyle e-commerce store with product bundle builders, review widgets, and mobile-optimized conversion funnels.
My Hilu
E-commerce storefront for pure graphene temperature-regulating blanket, featuring thermal technology visualizations and size/color swatches.
GetCarTablet
High-converting vehicle compatibility checker and direct-response sales funnel for wireless Apple CarPlay and Android Auto car tablets.
Specialized Shopify Engineering Services
From official Shopify App Store apps and custom direct-response funnels to speed optimization and complete Figma-to-theme migrations.
Shopify App Development (Public & Custom Embedded)
Full-stack Shopify applications built with React, Shopify Polaris, App Bridge, GraphQL Admin APIs, Node.js/Python, and cloud-native databases. From public multi-tenant App Store SaaS to proprietary private apps tailored to unique merchant workflows.
- Shopify Polaris UI & App Bridge v3 seamless admin integration
- High-throughput GraphQL Admin & Storefront API querying
- Idempotent webhook queue processing (Redis BullMQ / PostgreSQL)
- Shopify Recurring Application Charges (Billing API) & OAuth 2.0
- GDPR/CCPA mandatory compliance webhooks & App Store submission
Custom Shopify Theme Development (Online Store 2.0)
Clean, modular Liquid section architectures built from Figma prototypes or custom requirements. Zero slow page builders (GemPages, PageFly, Shogun) that ruin store load times. 100% merchant-editable through deep theme editor schema.
- Custom Liquid section architecture with reusable block schemas
- Zero-dependency native HTML5, modern CSS & Vanilla JS components
- Pixel-perfect conversion from Figma, Adobe XD & Sketch designs
- Mobile-first responsive layouts meticulously tested (320px–4K)
- WCAG AA accessibility & built-in JSON-LD Structured Data
Shopify Automation, Flow Workflows & Payment Gateways
Automate repetitive store operations, inventory syncing, and customer notifications using Shopify Flow, custom webhooks, and third-party integrations. Full configuration of Shopify Payments, Stripe, PayPal, and regional gateways with multi-currency support.
- Shopify Flow custom trigger, condition & action automation workflows
- Shopify Payments, Stripe, PayPal & local gateway setup & testing
- Multi-currency & international market routing via Shopify Markets
- Automated inventory restock, low-stock & order fulfillment triggers
- Webhook dispatchers to Slack, Klaviyo, Asana, Google Sheets & ERPs
Shopify Bug Fixes & Checkout Troubleshooting
Swift, surgical diagnosis and repair of broken Shopify functionality. Fix Liquid syntax errors, JavaScript conflicts, broken cart drawers, mobile layout glitches, and Shopify Checkout Extensibility issues before they cost you sales.
- Liquid syntax error repair and missing template recovery
- JavaScript console error debugging & jQuery conflict resolution
- Shopify Checkout Extensibility & One-Page Checkout customization fixes
- AJAX mini-cart drawer errors, sticky buy button & variant selector glitches
- Third-party app conflict auditing and script cleanup
Shopify 301 Redirects, Broken URL Fixes & SEO Migration
Prevent traffic drops and ranking losses during store redesigns or platform migrations (WooCommerce/Magento to Shopify). Comprehensive audit of broken URLs, automated bulk 301 redirection maps, and canonical hierarchy enforcement.
- Full website crawl & 404 broken URL discovery audit
- Bulk 301 redirect URL mapping with wildcard regex pattern matching
- Legacy platform URL migration (WooCommerce, Magento, BigCommerce)
- Google Search Console coverage error remediation & sitemap validation
- Canonical tag auditing to eliminate duplicate content penalties
Core Web Vitals & Sub-Second Speed Optimization
Surgical performance tuning for high-volume stores. Eliminate render-blocking scripts, refactor bloated libraries, optimize Shopify CDN media, and streamline the critical rendering path for maximum conversion rate and organic SEO lift.
- Cumulative Layout Shift (CLS) eradication (0.000 target)
- Largest Contentful Paint (LCP) reduction below 1.2 seconds
- Legacy jQuery removal and pure modern Vanilla JS refactoring
- Shopify CDN responsive image optimization (WebP/AVIF srcsets)
- Third-party app script auditing, deferral, and unblocking
Interactive Cost & Timeline Calculator
Configure your technical requirements to receive an instant timeline estimate and proposed budget range for your project.
Skills & Technology Stack
A battle-tested technology toolkit designed for high-conversion storefronts, compliant Shopify apps, and robust server architectures.
Shopify Core Ecosystem
Front-End & Modern Web
Backend, AI & Cloud Infrastructure
Trusted by Founders & Engineering Leaders
What clients, product managers, and Shopify store owners say about working with Nazmul.
"Nazmul delivered an extraordinary custom homepage on Shopify with 11 custom Liquid sections. We needed total flexibility to update our clinical procedures and copy without touching code, and he gave us 369 customizable settings! The speed is blazing fast (Lighthouse 93) and the zero-JS accordion for our SEO FAQ was genius."
"Working with Nazmul on our Shopify App Store application was seamless. He bridged our Python machine learning prediction backend with a beautiful React Polaris frontend in Shopify admin, handled GraphQL rate limits like a master, and built dynamic seasonal toolkits. Truly an elite Shopify App Engineer."
"Nazmul is our go-to senior developer for our most complex Shopify projects. On Myant Health, he engineered custom clinical compliance disclaimers, biometric sizing assistants, and responsive sections with immaculate Liquid code and zero delivery delays."
"Nazmul developed our 3 campaign landing pages including our custom Dutch postcode water quality diagnostic tool. Our lead capture rate jumped to over 18% immediately. His attention to mobile performance and conversion-driven UI is top-tier."
"Nazmul delivered flawless custom swatch selectors, spec matrices, and streamlined our customer PDP experience. Clean code, zero page builder bloat, and extraordinary communication throughout."
"Nazmul stepped in and completely stabilized our Shopify App Store application. He resolved our recurring billing webhook lifecycle, built an isolated shadow-DOM variant selector with zero theme CSS bleed, and guided us through official Shopify App Store approval."
Ready to Build on Upwork with Confidence?
All contracts, project milestones, and custom Shopify engineering engagements are securely processed through Upwork. Enjoy full escrow protection, transparent deliverables, and direct communication.
