AI-Aided In-House Development of Shopping Experiences Using Spree Open-Source eCommerce API and Next.js
The agentic software development revolution is rewriting who builds eCommerce — and how. In-house teams with domain knowledge can now design, build, and continuously improve tailored shopping experiences using AI coding assistants, a battle-tested open-source eCommerce API, and modern frontend tooling.
Spree Commerce provides the API-first backend foundation that makes this possible — natively supporting B2B commerce, multi-vendor marketplace, multi-store, multi-region, multi-tenant white-label SaaS eCommerce and digital product sales out of the box, with full data sovereignty, unlimited extensibility, and zero platform fees. No SaaS will ever be as tailored to a particular business case as what an empowered in-house team can build on open-source infrastructure.
In-House Developers with Domain Knowledge Are the New Masters of eCommerce
The most impactful software is built by people who understand the business problem deeply — not by generic platform vendors optimizing for the average customer.
In-house developers live inside the organization. They know the process pitfalls, the organizational bottlenecks, the edge cases that no SaaS vendor’s product manager has ever seen. They understand why the B2B checkout needs a purchase order field that triggers an approval workflow in a specific ERP. They know which fulfillment rules break during holiday peaks and why the pricing logic for a particular customer segment can’t follow standard discount tiers.
AI-powered development tools — from Claude Code and Cursor to GitHub Copilot — now amplify this domain knowledge into production-ready code at unprecedented speed. An in-house developer who understands the business can describe what they need in natural language and have an AI assistant scaffold the integration, write the API call, generate the test suite, and iterate on the UI — all in a fraction of the time traditional development required.
This is the shift: domain expertise becomes the bottleneck, not coding ability.
And in-house teams have more domain expertise than any agency or SaaS vendor ever will.
What In-House Teams Need Is a Solid API Foundation Built for Agentic Development
AI-assisted development doesn’t eliminate the need for good architecture — it makes architecture matter more. When an AI agent generates code faster than a human can review it, the underlying platform needs to be reliable, well-documented, API-first, and extensible without fragility.
This is exactly what Spree open-source eCommerce API provides.
Spree is an API-first, open-source eCommerce platform built for fast-growing businesses and enterprises. It comes with a fully-featured Storefront API for customer-facing applications and a Platform API for programmatic store management — both OpenAPI-documented, both designed for headless mode, both ready for AI agents to consume and generate code against.
Spree also ships with an AGENTS.md file for coding agents like Claude Code and Codex, plus a dedicated MCP server for AI-assisted commerce development — so AI tools can query Spree’s full documentation, understand the data model, and generate accurate integration code without hallucinating endpoints that don’t exist.
When your in-house developer tells Claude “add a webhook that syncs completed orders to our warehouse management system,” the AI agent can look up the webhooks documentation, generate a subscriber for the order.completed event, and wire it to your WMS API — all grounded in Spree’s actual architecture, not a best guess.
Spree Natively Supports the Complex Commerce Scenarios In-House Teams Actually Build
SaaS platforms force you into one business model and charge you for plugins when you need another. In-house teams building on Spree get native support for the commerce scenarios that actually match their business:
B2B eCommerce with customer-specific price lists, buyer organizations with role-based permissions, approval workflows, gated storefronts, and net payment terms.
Multi-vendor marketplace with automated vendor onboarding, product and order sync, split payments, and automated payouts via Stripe Connect.
Multi-tenant eCommerce for white-label SaaS platforms, franchise networks, and multi-brand enterprises — hundreds of independent stores on a single infrastructure.
Multi-store and multi-region operations with localized currencies, languages, tax rules, shipping methods, and payment methods — all managed from a single admin dashboard.
Digital product sales with automated delivery, configurable download limits, and digital-only checkout flows.
ChatGPT Instant Checkout via the Agentic Commerce Protocol for selling products directly within AI conversations.
These aren’t third-party plugins. They’re first-party modules that share a single composable architecture. An in-house team can launch a DTC store, add B2B wholesale next quarter, open a marketplace next year, and expand internationally the year after — all on the same platform, all with the same AI-assisted development workflow.
The Backend Is Extensible and Gives Full Data Sovereignty
Spree’s architecture is designed for in-house teams that need to own and customize every layer of their commerce stack. The clean separation between backend API and frontend application delivers concrete advantages:
Full data sovereignty. Your customer data, order history, product catalog, and business logic live on your infrastructure — AWS, GCP, Azure, or your own data centers. No vendor has access to your data. No platform terms-of-service can change how you use it.
Independent deployment cycles. Ship frontend updates hourly without touching the backend. Upgrade the commerce engine without breaking your storefront. Backend and frontend teams work in parallel without blocking each other.
Extensibility without fragility. Spree provides multiple extension mechanisms that keep customizations clean and upgrade-safe. Events and subscribers react to order completion, payment, and shipment changes. Webhooks notify external systems — ERPs, CRMs, warehouse management — in real time. Dependency injection lets you swap core services like tax calculators, shipping estimators, and serializers without forking the codebase.
AI-friendly codebase. The codebase is well-structured Ruby on Rails with clear separation of concerns, comprehensive test coverage, and thorough documentation. AI coding agents work most effectively on codebases with consistent patterns and explicit APIs — which is exactly what Spree provides.
Zero platform fees. No GMV cuts. No transaction fees. No per-store charges. The cost of running Spree scales with your infrastructure, not your revenue.
The Frontend Connects to Any Application in Any Technology
Spree’s headless API architecture means the commerce backend is completely decoupled from the frontend. Your in-house team connects Spree to whatever application they’re building — web storefront, mobile app, SaaS platform, kiosk, IoT device, or AI agent — using the same REST APIs.
For web storefronts, Spree provides a TypeScript SDK (@spree/sdk) and a dedicated Next.js integration package (@spree/next) with server actions, caching, and cookie-based authentication built in. A Spree-powered Next.js storefront deploys to Vercel in minutes with zero backend infrastructure to manage on the frontend side.
For mobile apps, the same Storefront API powers native iOS and Android applications. Spree’s documentation includes integration guides for Stripe on Android and iOS, and the API works with React Native, Flutter, or any HTTP client.
For SaaS platforms and custom applications, the Platform API provides full programmatic management — create stores, manage products, process orders, configure shipping — all through authenticated REST endpoints that any application can consume.
Backend-Heavy In-House Teams Can Design Storefronts with AI Tools Like v0
Here’s where the AI-aided development story gets particularly compelling for in-house teams that are strong on backend and domain logic but lighter on frontend design.
v0 by Vercel is an AI-powered frontend development tool that generates production-ready React and Next.js components from natural language descriptions. Describe the UI you want — a product grid with filtering, a B2B checkout flow with purchase order fields, a multi-step vendor onboarding wizard — and v0 outputs clean code using React Server Components, Tailwind CSS, and shadcn/ui primitives.
The workflow for an in-house team becomes:
Design in v0. Describe the shopping experience your business needs. Iterate on the layout, components, and user flows conversationally. v0 generates responsive, mobile-friendly Next.js code by default.
Connect to Spree. Wire the v0-generated frontend components to the Spree Storefront API using the @spree/sdk TypeScript SDK. Product listings, cart management, checkout, user accounts — the API handles the commerce logic while your frontend handles the experience.
Deploy to Vercel. Push to Git, deploy to Vercel’s edge network. Preview environments for every pull request. Production deployments in seconds.
Iterate continuously. Your in-house team knows which parts of the shopping experience need improvement because they see the data and hear the feedback. Use v0 and AI coding assistants to iterate on the frontend while Spree handles the commerce complexity behind the API.
This isn’t a theoretical workflow. It’s the direct result of API-first architecture meeting AI-powered frontend tooling. Backend-heavy teams no longer need to hire a frontend agency to get a polished storefront — they can direct the AI with their domain knowledge and get something more tailored than any template could provide.
Enterprise Edition Adds Purpose-Built Modules for Complex Commerce
The Enterprise Edition for complex commerce scenarios extends the open-source foundation with purpose-built modules for complex commerce scenarios and enterprise-grade security.
Multi-vendor Marketplace module. Automated vendor onboarding from Shopify, WooCommerce, or CSV. Two-way product and order sync. Split payments and automated vendor payouts via Stripe Connect. Full marketplace admin dashboard with commission management, vendor approval workflows, and merchandising controls.
B2B eCommerce module. Customer-specific price lists and customer group segmentation. Buyer organizations with role-based permissions and approval workflows. Gated storefronts, volume pricing, and ERP integration.
Multi-tenant eCommerce module. Host hundreds of independent stores on a single multi-tenant infrastructure. Each tenant gets their own dashboard, storefront, and branding. Central control over billing, payments, fulfillment, and operations. Supports white-label SaaS, franchise networks, and multi-brand enterprises.
Enterprise security by default. Security-hardened architecture aligned with SOC 2 Type 2 and ISO/IEC 27001 standards. AES-256 encryption at rest, TLS 1.3 in transit. SSO with any SAML/OIDC provider. PCI DSS compliance with tokenized payments. Role-based access control with granular permissions. Comprehensive audit logging. Continuous security patches through the Long-Term Support program.
Enterprise Support Comes from the Team That Builds the Platform
In-house teams building on Spree don’t need to figure everything out alone. Enterprise support is backed by the same engineers who build and maintain the platform:
A dedicated success manager as your single point of contact. SLA-backed response times with guaranteed resolution windows by severity. Direct access through Slack, Microsoft Teams, or email. Long-Term Support with extended maintenance and predictable upgrade cycles. Priority access to fixes and new features. 24/7 infrastructure monitoring with proactive alerting for managed hosting customers. On-demand professional services for custom integrations, architecture reviews, and implementation guidance.
This is the support model that makes in-house development viable at enterprise scale — expert help when you need it, full independence when you don’t.
No SaaS Will Ever Match What an Empowered In-House Team Can Build
The promise of SaaS eCommerce was that you wouldn’t need to build anything. The reality is that every growing business eventually needs something the SaaS platform doesn’t support — and then you’re trapped in plugin hell, paying for workarounds, waiting on a vendor’s roadmap.
The agentic software development revolution inverts this equation. In-house developers armed with AI coding assistants, domain knowledge, and a solid open-source foundation like Spree can now build commerce experiences that are more tailored, more flexible, and more maintainable than anything a SaaS platform could offer.
Spree provides the foundation: a battle-tested open-source eCommerce API with native support for every complex commerce scenario, clean extension points for unlimited customization, full data sovereignty, and an architecture that AI agents can work with effectively. Your in-house team provides what no vendor ever can: deep understanding of your business, your customers, and your competitive advantage.
The tools are ready. The platform is ready. The only question is whether your team is ready to stop renting someone else’s vision of eCommerce and start building your own.
Get started building your commerce platform or book a meeting to explore what your in-house team can build.
