Custom apps and extensions
BEYOND PUBLIC APPS
Custom apps and extensions
BEYOND PUBLIC APPS
Private apps, checkout functions, and admin extensions tailored to your business logic.
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Shopify clients

What we build
We build custom applications and intelligent integrations that handle the complex business logic and system connections that public apps can't address.
Private apps with admin UI, checkout functions, app extensions, and custom integrations. Built for business logic that public apps don't support or requirements that need complete control.
Real-time synchronization with enterprise systems. Inventory management, order routing, product information sync, and financial system integration that maintains data consistency.
AI-powered processes that learn from your operations. Intelligent order routing, dynamic pricing, predictive inventory management, and customer service automation that adapts to business patterns.
Our approach
We start by understanding your business operations, then architect systems that integrate seamlessly while maintaining the reliability your business depends on.
We map your current systems, identify integration points, and define exactly what success looks like. Clear requirements prevent scope creep and ensure we build what you need.
Before custom development, we evaluate existing solutions and APIs. Sometimes a configuration change or public app solves the problem faster and cheaper than custom code.
System design, API security, data flow architecture, and permission models. We design for reliability, scalability, and security before writing any code.
Iterative development with regular testing against real data. Apps, integrations, and workflows are built incrementally with continuous validation.
Comprehensive testing including error handling, data consistency, performance under load, and failure recovery. We test edge cases that break integrations in production.
Controlled deployment with monitoring, alerting, and maintenance processes. You get a system that works reliably with clear procedures for ongoing operations.
Fit
We'll recommend public apps and standard integrations when they solve your problem. Custom development makes sense when your requirements outgrow what existing solutions can deliver.
Public apps and standard integrations work when
Many integration needs are common enough that well-built public apps already solve them. Custom development should be the exception, not the default approach.
If your business operates within common patterns, existing integrations and apps probably handle your use cases more reliably than custom code.
Sometimes changing your workflow to match available apps is faster and cheaper than building custom solutions. We'll help you evaluate this trade-off honestly.
Shopify developmentCustom integrations make sense when
Complex pricing rules, unique fulfillment processes, or industry-specific workflows that public apps can't handle require custom development.
Multi-system data synchronization, real-time inventory across multiple channels, or custom ERP workflows often need purpose-built integrations.
Custom admin interfaces, checkout functions that modify business logic, or app extensions that integrate deeply with Shopify's interface.
Engagement
Whether you need a feasibility assessment, a custom integration built, or ongoing operations support, we have engagement models that fit different stages of your integration journey.
From $5,000 USD
Fixed scope assessment with clear recommendations and implementation roadmap.
Who it is for
For teams that need to understand what's possible with Shopify integrations, evaluate build vs buy decisions, and get a roadmap before committing to custom development.
What is included
How it ends
Ends with a clear recommendation on the best path forward and detailed implementation plan if custom development is recommended.
From $5,000 USD
Scoped to specific integration requirements. Timeline and price depend on system complexity.
Who it is for
For businesses with defined integration requirements that need custom apps, API connections, or workflow automation built and deployed.
What is included
How it ends
Results in a working integration with clear maintenance procedures and monitoring in place.
From $2,500 per month USD
Ongoing maintenance, enhancements, and new integrations. We suggest six months minimum for meaningful system evolution.
Who it is for
For teams with existing integrations that need ongoing maintenance, new features, system updates, and continuous optimization of their integration landscape.
What is included
How it ends
Runs as an ongoing partnership with proactive system management and regular capability expansion.
Not sure what type of integration you need? Book a meeting with the team.
Complementary services
Integrations often connect with other aspects of your Shopify system. These services frequently pair with custom app development for complete solutions.

Let's meet
Looking to scale revenue on Shopify? You'll book directly with Dusan J., Founder at EXTFOX, to discuss your store, opportunities, and next steps.
Pick a time that works for you. You'll get instant confirmation and a calendar invite.
Prefer to call? (862) 259-6969
Build custom when your business logic doesn't fit existing apps, you need complete control over data and features, or you require deep integration with other systems. Public apps work for common use cases, but custom apps are necessary when your requirements are unique, you need specific admin UI, or existing apps create operational friction.
Private apps are built specifically for your store and business needs. They're not listed in the App Store and can access your store's data directly. Public apps are distributed through Shopify's App Store and must work for multiple merchants. Private apps give you complete control but require maintenance. Public apps offer broader support but less customization.
ERP integration complexity depends on data synchronization needs, real-time requirements, and system architecture. Simple integrations might sync inventory and orders nightly. Complex setups require real-time inventory updates, multi-location fulfillment routing, and bidirectional data flow. We assess your specific ERP system and design appropriate integration architecture.
Agentic workflows use AI to automate and optimize business processes that traditionally require human decision-making. Examples include intelligent order routing based on inventory and customer location, dynamic pricing that responds to demand patterns, and automated customer service that escalates appropriately. They adapt to your business patterns and improve operations over time.
Timeline depends on app complexity and integration requirements. Simple admin apps might take 4-6 weeks. Complex integrations with external systems typically require 8-16 weeks. Agentic workflows with AI components can take longer. We provide detailed timelines during the architecture phase based on your specific requirements and technical complexity.
Integrations need ongoing maintenance for API version updates, security patches, performance monitoring, and feature enhancements. Shopify regularly updates APIs, and connected systems evolve. We provide maintenance retainers that include monitoring, updates, and enhancements so your integrations stay reliable and current.