Shopify Apps & Plugins
- Checkout Extensions
- Subscription Systems
- ERP & CRM Integrations
When the app store doesn't have what you need, we build it. Custom apps for your store, public App Store apps, checkout extensions: whatever your store requires.
We are a London engineering team building on Shopify and Shopify Plus, BigCommerce, Salesforce Commerce Cloud and NetSuite SuiteCommerce. Work is quoted fixed after a discovery scan and starts from £4,000 for a custom app; timelines depend on the shape of the build. Migrations start from £15,000 and are quoted after a one-week discovery and a written risk register.
It suits mid-market retailers and B2B sellers who have outgrown a theme or an agency retainer and want a senior engineer, a written scope and a rollback plan. The full band for every service is in the cost table further down this page.
What we build
From quick fixes to full platform builds. Here's how we help ecommerce brands grow.
Theme Development
- Mobile-First Design
- Core Web Vitals Budgets
- Accessible Checkout Flows
Themes that load fast and sell well. We work with Shopify 2.0 and BigCommerce Stencil to build stores that load fast on phones and pass Core Web Vitals.
Headless Commerce
- Hydrogen & Oxygen
- Next.js Storefronts
- Multi-Channel Delivery
For brands that need more control. We build React frontends on Hydrogen, Next.js, or custom stacks, backed by Shopify or BigCommerce.
AI & LLM Integration
- LLM-Powered Semantic Search
- GPT-Integrated Product Advisors
- Predictive Inventory & Pricing
AI built into your store's search and catalogue, not a chatbot on top. We build LLM-powered product discovery, intent-aware search, and predictive systems for pricing and inventory.
Salesforce Commerce Cloud
- SFRA & Headless Commerce API
- CRM & Marketing Cloud Integration
- B2C & B2B Commerce
Enterprise-grade commerce with deep CRM integration. We build SFCC storefronts, custom cartridges, and connect your commerce to Sales, Service, and Marketing Cloud.
NetSuite SuiteCommerce
- SuiteCommerce Advanced
- Real-Time ERP Sync
- Multi-Channel Order Management
When your storefront needs to talk directly to your ERP. We build SuiteCommerce solutions with real-time inventory, order management, and financial data sync.
From scope to launch and beyond
We are an engineering team, not a marketing agency. Every engagement runs the same way: a written scope, code reviewed by a second engineer, and a price held firm once it is agreed. Here is exactly what working with us looks like.
- 01
Discovery
A scoping call to map the actual problem: current platform, the constraint you have hit, and the outcome you need. No generic pitch deck; we come with questions about your stack.
- 02
Written statement of work
Before any code, you get a written SOW: scope, milestones, acceptance criteria, and a realistic schedule. The price is fixed in writing once the scope is agreed, never an optimistic estimate that quietly slips.
- 03
Build, reviewed
Work ships as pull requests into your repository, each reviewed by a second engineer before it merges. You see progress as commits, not status-meeting summaries.
- 04
QA and launch
Every build is tested against the platform it targets (theme, Hydrogen storefront, or Shopify Plus customisation) with Core Web Vitals and checkout flows verified before go-live.
- 05
Optional retainer
Most clients stay on an engineering retainer afterwards. The relationship compounds because we keep the context about your codebase instead of rebuilding it every time.
What every engagement includes
- →A written statement of work with milestones and acceptance criteria
- →Code shipped as pull requests, reviewed by a second engineer
- →Documentation and a handover walkthrough with the engineer who built it
- →Core Web Vitals and checkout verified before launch
- →A fixed price, held firm in writing once scope is agreed
Ways to engage us
Fixed-scope project
Well-defined work with a clear finish line, timed to its scope and complexity. One SOW, one price, milestone-based delivery.
Engineering retainer
Ongoing development, performance work, app updates, and new features against a monthly engineering allocation. Best when the roadmap keeps moving.
Hybrid programme
A fixed-scope build to launch the core, then a retainer to iterate. Phased delivery for larger replatform or migration programmes.
Scoped service pages
Most engagements start from one of these. Each page covers the deliverables, timeline, and how we price the work.
Why teams choose No7
We're not the cheapest option, but we do things properly. Here's what that means.
Code You Can Maintain
We write code that your next developer can actually understand. Properly documented, sensibly structured.
Fast Stores
Every site we build hits Core Web Vitals thresholds (LCP under 2.5s). Slow stores lose sales; we make sure yours doesn't.
Secure & Compliant
GDPR-ready implementations with proper data handling. No cutting corners on security.
Ongoing Support
We offer retainer packages for clients who need regular updates and maintenance.
What our eCommerce development services cost
Fees are GBP, ex VAT, and are the bands the last twelve months of engagements landed in. Firm pricing goes in writing after a discovery scan. Each row links to the page with the full scope.
| Service | Typical fee | Duration | Detail |
|---|---|---|---|
| Custom Shopify app (single store, single purpose) | From £4,000 | Set after discovery | Shopify app development |
| Shopify Plus build (theme, Functions, B2B) | From £15,000 | Set after discovery | Shopify development |
| Headless Hydrogen storefront | From £20,000 | 12 to 20 weeks | Headless Shopify development |
| Custom BigCommerce Stencil theme | From £15,000 | 6 to 10 weeks | BigCommerce development |
| BigCommerce Catalyst headless build | From £20,000 | 10 to 18 weeks | BigCommerce development |
| Migration to Shopify Plus | From £15,000 | Set after a 1-week discovery | Shopify Plus migration |
| Technical Shopify SEO | Quoted on the discovery call | 1-week audit, 2 to 6 weeks of fixes | Shopify SEO services |
| AI Visibility Sprint | £1,999 fixed | 14 days | AI Visibility Sprint |
How we scope a platform engagement
Most engagements start with a platform decision before any code is written. If you are weighing where to build or replatform, our engineering comparisons lay out the trade-offs the way we assess them internally: Shopify Plus vs BigCommerce Enterprise, Shopify Plus vs Adobe Commerce, Shopify Plus vs commercetools, Adobe Commerce vs Salesforce Commerce Cloud, and Shopify Plus vs NetSuite SuiteCommerce.
When the decision is a migration, the engineering risk sits in data mapping and redirect strategy, not the build itself. We cover the full process in our platform migration checklist and a worked example in the Volusion to BigCommerce migration guide. Ready to scope one? Request a migration assessment.
Frequently asked questions
Agency, company or freelancer for ecommerce development?
Pick by the shape of the work, not the label. A freelancer suits a bounded theme or app task with one owner. An agency suits a launch that needs design, content and build together. An engineering company suits integration-heavy work: ERP, PIM, 3PL and payment connections, custom apps, headless storefronts and migrations, where the risk is in the data flows rather than the pages. Whoever you choose, ask who owns the code, how the scope is fixed in writing and what the hypercare period covers.
What Shopify Plus services do you offer?
Full Shopify Plus engineering: custom app development (public and private), Checkout Extensions, Shopify Functions, B2B catalogue and price list setup, Hydrogen headless storefronts, Shopify Flow automation, and complex migrations from Shopify Advanced or competing platforms.
Can you build BigCommerce multi-storefront setups?
Yes. We architect BigCommerce multi-storefront implementations with shared catalogues, region-specific pricing, and localised checkouts. We also handle Stencil theme work and headless builds using the Storefront API.
Do you work with Salesforce Commerce Cloud (SFCC)?
We build SFRA storefronts, author custom cartridges, integrate SFCC with Sales Cloud and Service Cloud via OCAPI and SCAPI, and coordinate deployments through the SFCC sandbox/staging/production pipeline.
Can you integrate our NetSuite ERP with our storefront?
This is one of our most-requested projects. We build real-time, bi-directional integrations between Shopify, BigCommerce, or custom storefronts and NetSuite, syncing orders, inventory, customers, items, and fulfilment events using SuiteTalk, SuiteScript, and custom middleware where needed.
How do you scope and price projects?
Fixed-scope projects for well-defined work (a Shopify Plus build starts from £15,000, and its timeline depends on scope and complexity), hourly retainers for ongoing development, and hybrid arrangements for phased programmes. Every scope includes a written statement of work with milestones, acceptance criteria, and realistic timelines. Never optimistic ones that slip.
Do you handle maintenance and support after launch?
Yes. Most of our clients stay on a retainer for ongoing engineering, performance monitoring, app updates, new feature development, and emergency response. The relationship compounds because we keep the context about your codebase rather than rebuilding it every engagement.