# EssDeeJay — The SJ Development > EssDeeJay (The SJ Development) is a Toronto development agency with deep Shopify expertise. We also build Webflow websites, mobile applications and custom software, with focused scope and quick turnaround. Official website: https://www.thesjdevelopment.com/ Project enquiries: https://www.thesjdevelopment.com/contact Projects are scoped individually. Use the contact page to confirm scope, pricing, availability and delivery dates. Service pages describe capabilities; case-study outcomes apply to the projects described and are not guarantees for other stores. ## Services - [Shopify Theme Development](https://www.thesjdevelopment.com/services/theme-development.md): Custom Shopify theme development using Liquid, theme blocks, Online Store 2.0, accessibility and Core Web Vitals best practices. Best suited to: Brands outgrowing an off-the-shelf theme; Teams blocked by developer-only content changes; Stores carrying theme debt from years of apps; Replatforms that need SEO and conversion continuity. - [Custom Shopify App Development](https://www.thesjdevelopment.com/services/app-development.md): Custom Shopify app development with GraphQL Admin API, Functions, Admin UI extensions, Sidekick extensions and production observability. Best suited to: A proprietary workflow no public app supports; Teams paying for several overlapping apps; B2B, pricing or fulfillment rules that create advantage; Software products extending into the Shopify ecosystem. - [Mobile Application Development](https://www.thesjdevelopment.com/services/mobile-development.md): Custom iOS and Android app development for customer apps, bookings, memberships and business tools. Shopify integrations available. Toronto-based, working worldwide. Best suited to: Businesses launching their first mobile product; Booking, membership and customer service apps; Teams replacing manual field workflows; Shopify brands building a mobile shopping experience. - [Webflow Website Development](https://www.thesjdevelopment.com/services/webflow-development.md): Webflow website development, landing pages, CMS setup and redesigns. Launch with responsive layouts, SEO foundations and a practical content handover. Best suited to: Service businesses refreshing their website; Marketing teams launching campaigns; Founders building an initial web presence; Teams who need an editable content library. - [Custom Software & Web Development](https://www.thesjdevelopment.com/services/custom-development.md): Custom web applications, MVPs, portals and internal tools with focused delivery and quick turnaround. Define the first release with EssDeeJay. Best suited to: Founders validating an MVP; Teams replacing spreadsheet workflows; Businesses needing customer or partner portals; Projects needing functionality beyond a site builder. - [Shopify Performance Optimization](https://www.thesjdevelopment.com/services/performance.md): Shopify speed optimization for LCP, INP and CLS through Liquid profiling, script audits, media strategy and real-user performance monitoring. Best suited to: Stores failing Core Web Vitals on key templates; Themes slowed by years of app changes; Redesigns that look good but feel unresponsive; Teams unable to explain lab-versus-field performance. - [Shopify SEO, AEO & GEO Optimization](https://www.thesjdevelopment.com/services/seo-geo.md): Shopify SEO, AEO and GEO optimization for technical search, structured data, Shopify Catalog, agentic storefronts and international markets. Best suited to: Stores losing non-brand organic visibility; Brands preparing for AI shopping channels; International Shopify Markets expansion; Catalogs with inconsistent product attributes. - [Shopify Conversion Rate Optimization](https://www.thesjdevelopment.com/services/cro.md): Shopify conversion rate optimization using customer research, Web Pixels, funnel analysis, checkout optimization and Shopify Rollouts experiments. Best suited to: Stores with meaningful traffic but weak conversion; Teams shipping changes without reliable learning; High-consideration catalogs with comparison friction; Brands preparing a redesign or checkout change. - [Shopify UX & UI Design Improvements](https://www.thesjdevelopment.com/services/ux-ui.md): Shopify UX and UI design for accessible navigation, product discovery, checkout, customer accounts, design systems and mobile commerce journeys. Best suited to: Stores with confusing navigation or product choice; Brands with inconsistent components across templates; Teams improving accessibility and inclusive design; B2B or account journeys with dense information. - [AI Development for Shopify](https://www.thesjdevelopment.com/services/ai-development.md): Shopify AI development for semantic search, recommendations, agentic commerce, UCP, MCP, Sidekick extensions and controlled automation. Best suited to: Catalogs where keyword search misses buyer intent; Teams needing faster access to operational knowledge; Brands preparing for agentic commerce; Recommendation problems with enough quality data. - [Shopify Business Automation](https://www.thesjdevelopment.com/services/automations.md): Shopify automation using Shopify Flow, GraphQL Admin actions, HTTP requests, app connectors and event-driven fulfillment workflows. Best suited to: Teams repeating order or customer administration; Operations scaling faster than headcount; B2B onboarding and account workflows; Stores coordinating several apps and fulfillment paths. - [Shopify Software Integrations](https://www.thesjdevelopment.com/services/integrations.md): Shopify integration development for ERP, CRM, PIM, WMS and 3PL systems using GraphQL Admin API, webhooks and observable event architecture. Best suited to: ERP or accounting migrations; Multi-location inventory and fulfillment; Product data managed in a PIM; Stores replacing fragile point-to-point connectors. ## Business and project enquiries - [About the agency](https://www.thesjdevelopment.com/): Shopify specialists also building websites, mobile apps and custom software. - [All services](https://www.thesjdevelopment.com/services): Compare Shopify, Webflow, mobile and custom development. - [Website sitemap](https://www.thesjdevelopment.com/sitemap): Browse the complete page directory. - [Contact](https://www.thesjdevelopment.com/contact): Share goals, requirements, budget and timeline to request a scoped estimate. - [Work and case studies](https://www.thesjdevelopment.com/work): Client project overviews, website galleries and project stories. - [Full service and knowledge guide](https://www.thesjdevelopment.com/llms-full.txt): Service details, project stories, FAQs and published articles in one text file. ## Client project stories - [Umbra: Design-led discovery for everyday living](https://www.thesjdevelopment.com/work/umbra-performance-optimization.md): A homeware storefront that connects room-by-room browsing, designer stories and a wide product catalogue. - [Maison Bouquet: A floral shop with room for everyday occasions](https://www.thesjdevelopment.com/work/maison-bouquet-floral-storefront.md): A Moncton floral storefront bringing bouquets, subscriptions and personal enquiries into one welcoming experience. - [Vraj & Co.: Bringing the colour of a spice collection online](https://www.thesjdevelopment.com/work/vraj-co-spice-storefront.md): A colourful spice storefront with clear product families, packaging-led discovery and a public web-development credit for Shreyank Jadiya. - [Village Juicery: Fresh products, connected to local routines](https://www.thesjdevelopment.com/work/village-juicery-local-commerce.md): A Toronto food and juice storefront connecting product discovery with local delivery, pickup and physical locations. - [Square Flower: A calmer way to explore better bedding](https://www.thesjdevelopment.com/work/square-flower-bedding-storefront.md): A bedding storefront combining bedroom photography, colour-led product discovery and material education. - [Harlow Properties: From finding a rental to feeling at home](https://www.thesjdevelopment.com/work/harlow-properties-webflow-website.md): A Moncton property website connecting available rentals, property services and enquiries through a clear Webflow experience. - [Greenworks Tools: Headless to theme migration for a global brand](https://www.thesjdevelopment.com/work/greenworks-tools-migration.md): How we migrated a complex headless Shopify setup to a blazing fast Online Store 2.0 theme, increasing conversion by 24%. ## Insights - [Shopify Sidekick Tips: 5 Practical Workflows for Your Store](https://www.thesjdevelopment.com/blog/shopify-sidekick-workflow-tips.md): Use Shopify Sidekick for focused reporting, theme changes and Flow drafts. Five practical prompts and a review checklist, updated for September 2026. - [Shopify Multiple Barcodes: A Practical Setup and Testing Checklist](https://www.thesjdevelopment.com/blog/shopify-multiple-barcodes-guide.md): Shopify now supports multiple barcodes per variant. Learn what changed in September 2026 and how to test your POS, product data and integrations before rollout. - [Shopify Search & Discovery: 5 Product Filter Improvements to Try](https://www.thesjdevelopment.com/blog/shopify-search-discovery-filter-tips.md): Make Shopify product filters easier to use with cleaner attributes, focused choices and a mobile testing checklist. Practical Search & Discovery tips for 2026. - [Shopify Agentic Commerce SEO: How to Make Your Products Discoverable in AI Shopping](https://www.thesjdevelopment.com/blog/shopify-agentic-commerce-geo-guide.md): A practical 2026 guide to Shopify agentic commerce, AEO and GEO—covering product data, answer-ready content, structured signals and measurement. - [Shopify Scripts Are Gone: A Practical Migration Guide to Shopify Functions](https://www.thesjdevelopment.com/blog/shopify-scripts-to-functions-migration.md): Shopify Scripts stopped executing on June 30, 2026. Learn how to audit broken logic, map it to Functions, test safely and recover checkout behavior. - [Shopify B2B on Every Plan: The 2026 Guide to Wholesale Without the Patchwork](https://www.thesjdevelopment.com/blog/shopify-b2b-all-plans-guide.md): Shopify now offers foundational B2B capabilities on Basic, Grow and Advanced. Learn what is included, what Plus adds, and how to design the right wholesale setup. ## Optional - [Sitemap](https://www.thesjdevelopment.com/sitemap.xml): Canonical public pages. - [Insights feed](https://www.thesjdevelopment.com/blog-feed.xml): Published article feed. - [Privacy policy](https://www.thesjdevelopment.com/privacy): Website privacy information. - [Terms and conditions](https://www.thesjdevelopment.com/terms): Website terms.