Service Shopify Apps

Introduction

Shopify app development UK continues to be a strong route for merchants who need features beyond out-of-the-box themes and plugins. If your store in London, Manchester or elsewhere in the UK needs a specific checkout flow, an ERP integration, or custom analytics, a bespoke Shopify app can be the cleanest, most reliable solution. At Xiza Digital we build apps that reduce manual work, improve conversion and scale with your business.

When you need a custom Shopify app

Not every store needs a custom app. Shopify's App Store contains thousands of solutions that cover marketing, shipping, subscriptions and more. But there are clear situations where a custom Shopify app is the right choice:

• Unique business logic: Custom pricing, tiered discounts, or checkout rules that off-the-shelf apps can't handle.
• Systems integration: Connecting to a bespoke ERP, head office database, warehouse management system or a local courier API used in the UK and EU.
• Automation & scale: Replacing repetitive manual tasks (order tagging, re-routing, data sync) with automated jobs to save hours per week.
• Performance & control: When you need direct control over data handling, caching, or background jobs to keep large catalogues fast.
• Brand experience: Adding functionality to a headless storefront or creating a unique customer journey in the cart or checkout.

Examples we've seen in London and across the UK include bespoke subscription handling for a cosmetics retailer, a returns routing app for multiple warehouses, and a wholesale price matrix for B2B customers. If standard apps force you into workarounds or manual processes more than a few times a week, it’s usually time to build a custom app.

Public vs private apps

Choosing between a public and private app is one of the first decisions in any Shopify app development project. Here’s a simple breakdown to help:

Public apps

• Listed on the Shopify App Store and available to any merchant.
• Must meet Shopify's app review and security requirements.
• Suitable if you plan to sell or support the app for multiple stores — good for productised solutions.
• Requires time for compliance, documentation and ongoing support for multiple customers.

Private (custom) apps

• Installed only on the merchant(s) you select; not listed publicly.
• Faster to deploy for a single client or a small number of stores.
• Ideal for bespoke integrations (e.g., connecting to a UK-based fulfilment house or a custom back office).
• Lower initial overhead but expect less standardisation and more bespoke maintenance.

Which should you choose? If you’re solving a problem unique to your business, a private app is frequently the right route. If the functionality could help other merchants and you want to monetise it, build a public app and prepare for the extra work around billing, support, and Store listing.

Our Shopify expertise (ConvertLab)

At Xiza Digital we combine practical ecommerce experience with disciplined engineering. Our in-house capability, ConvertLab, focuses on conversion-focused Shopify work — from small private apps to scalable public services. Learn more about ConvertLab on our ConvertLab page to see how we approach experimentation and optimisation across Shopify stores.

What this means for you:

• We design for Shopify’s architecture — using best-practice Shopify APIs, webhooks and recommended app patterns.
• We optimise for retailer realities in the UK: local VAT handling, multi-currency pricing, and integrations with UK couriers and payment gateways.
• We build secure, maintainable apps and document them so your team or another developer can pick things up later.

For examples of our work, see our portfolio where we showcase apps, custom integrations and store builds across the UK and beyond.

App development process

We follow a practical, transparent process that keeps you in control. Below is a high-level roadmap we typically follow for Shopify app development in the UK:

1. Discovery (1–2 weeks)

• Talk through the problem with your team — we map the current workflow and identify pain points.
• Prioritise requirements and decide whether an off-the-shelf app is sufficient.
• Produce a short technical brief and estimate.

2. Specification & planning (1–2 weeks)

• We convert the brief into user stories, API needs and wireframes for admin/user screens.
• Decide on public vs private, hosting, data ownership and compliance (GDPR, GDPR for EU customers if applicable).
• Provide a fixed-price estimate or time & materials plan with milestones.

3. Build & iterative delivery (4–12 weeks)

Development time varies by complexity:

• Small private app (simple webhook + admin UI): typically £3,000–£8,000 and 2–6 weeks.
• Medium app (multiple integrations, background jobs): typically £8,000–£25,000 and 6–12 weeks.
• Large/enterprise (complex API orchestration, multi-region): often £25,000+ and 3+ months.

During build we deliver in sprints, demo functionality regularly, and keep a shared backlog so you can decide priorities as we go.

4. Testing

• Automated tests for core flows and manual QA across different stores and scenarios.
• Security checks (OWASP basic checks, secrets handling), and performance testing when handling high-volume order data.
• Beta testing on a staging store or with a small set of users before full launch.

5. Deployment & documentation

• We deploy to a secure hosting environment and provide clear setup instructions.
• Documentation includes admin steps, upgrade notes and a runbook for common issues.

6. Support & evolution

Post-launch we offer tailored maintenance plans. Many UK merchants prefer a retainer for:

• Regular dependency updates (Shopify API changes, Ruby/Node package updates).
• Small feature tweaks and performance patches.
• Priority bug fixes — typical retainer bands start at around £500–£1,500 per month depending on SLA.

App Store publishing

If you choose a public app, publishing on the Shopify App Store is a formal process with checks for security, billing, UX and documentation. Here’s what to expect:

1. Prepare your app listing: clear description, screenshots, setup guide and a support contact.
2. Implement Shopify's billing API if you intend to charge — we can advise on pricing models (one-off, subscription, usage-based).
3. Pass Shopify’s review process — this can take 1–4 weeks depending on issues found.
4. After approval, monitor take-up and be ready to support merchants who install the app.

Public apps also require ongoing compliance: responding to security disclosures, maintaining compatibility with new Shopify API versions, and keeping clear documentation. We help with the initial submission and can manage app updates and reviews on your behalf.

Costs and timelines — realistic expectations

We believe in being upfront. Typical cost and time estimates for Shopify app development in the UK are:

• Simple private app: £3k–£8k, 2–6 weeks.
• Mid-level app with integrations: £8k–£25k, 6–12 weeks.
• Large or public app with monetisation: £25k+, 3+ months plus ongoing support.

Why the range? Integration complexity (ERP, customs, shipping rules), the number of edge cases, and whether you want the app listed publicly all affect price and time. We recommend budgeting for post-launch support — even a small app benefits from 3–6 months of minor tweaks after go-live.

When Xiza isn’t the right fit

We’re honest about scope and fit. Xiza is a great fit for UK merchants and mid-market brands that need pragmatic, reliable engineering and a partner who understands ecommerce. There are scenarios where we might recommend an alternative:

• Very large enterprise programmes with multi-year, multi-team demands and an existing on-premise engineering team — these often require a different commercial model.
• Projects requiring specialist compliance (e.g., regulated financial services or medical-grade systems) outside our core expertise.
• When you need a high-volume SaaS platform built from scratch for thousands of merchants in the first year — we can do this, but it’s a different resourcing conversation.

When we aren’t the perfect match, we’ll say so and, where appropriate, point you to other specialists or suggest a phased approach that reduces risk.

Case study snapshots

To make the above concrete, here are very short anonymised examples from our portfolio:

• Subscription flow remodel (London-based beauty retailer): Replaced three separate apps with a single private app that handled billing, proration and dunning — reduced manual tickets by 75% and increased subscription retention by 12% after six months. (See more examples in our portfolio.)
• Wholesale price matrix: Built a private app to calculate prices by customer group, SKU attributes and order volume — saved 8 hours/week for the sales team and supported 2,500 SKUs without performance issues.
• Public app launch: We took a receipt-generation app from prototype to the Store: implemented billing, review fixes and support guides, and achieved approval in three weeks.

How we work with UK merchants

Working with retail and B2B clients in London, Birmingham and Manchester means we know local shipping patterns, VAT complexities and typical integrations used by UK fulfilment houses. We prefer clear communication: fortnightly demos, a shared backlog, and straightforward invoices. If you want, we’ll run discovery in person around London or via video call if you’re elsewhere in the UK.

What we need from you to start

• Access to a development Shopify store or a staging environment.
• Clear list of must-haves vs nice-to-haves.
• Access to APIs or credentials for third-party systems you want integrated.
• A decision-maker who can sign off on scope and testing timelines.

FAQ

How long does it take to build a custom Shopify app?

Small private apps can be delivered in 2–6 weeks. Mid-sized projects are usually 6–12 weeks. Larger, multi-integration public apps often take 3+ months. Exact timelines depend on integrations, compliance and how quickly you can test and provide feedback.

Will a custom app affect my Shopify Plus checkout?

Shopify Plus provides more flexible checkout customisation via Checkout Extensibility and Scripts. We’ll design the solution to work with your plan: some checkout changes require Plus, but many business logic needs can be handled in-app without touching checkout Liquid. We’ll advise the best approach in discovery.

Do you support ongoing maintenance in the UK timezone?

Yes. We are UK-based and support merchants across London and the UK. We provide options for local business hours SLAs and can be available for emergency fixes if you take a retainer.

Conclusion

Custom Shopify app development in the UK can unlock efficiencies and experiences that off-the-shelf apps can’t deliver. Whether you need a private integration to your ERP, a public app to sell to other merchants, or a conversion-focused tool built by our ConvertLab team, we focus on pragmatic engineering and honest estimates. If you’re in London or elsewhere in the UK and want to explore whether a custom app is right for your store, check our services, review our portfolio and get in touch.

Ready to talk? Message us on WhatsApp for a quick chat about your project — we’ll scope the problem and suggest the best next step.