Three options per product. Shopify raised the variant ceiling to 2,048 in October 2025, but the option ceiling stayed at three. Sell anything genuinely configurable and that is a wall, not an inconvenience.
Ecommerce engineering
Custom Shopify development for businesses hitting the platform ceiling
You do not need to leave Shopify. You need the 20% Shopify cannot do. We build the custom systems, integrations and AI that sit alongside your store, so the platform keeps doing what it is good at and stops being the reason you cannot ship.
Where Shopify actually stops
These are not bugs. They are what a hosted platform is.
Shopify is very good software. They become your problem at a predictable point in growth.
Checkout belongs to Shopify. Deep checkout customisation is gated behind Plus, and even there it runs inside Shopify's rules. If your business logic lives at checkout, approval flows, complex fulfilment promises, negotiated terms, you are working against the platform.
Multi-brand and multi-region means multiple stores. Separate subscriptions, separate admin, and no shared inventory or unified customer record by default. Every operator running three brands has built the same fragile spreadsheet.
API rate limits become your architecture. At volume, what you can build stops being a design decision and starts being a quota decision.
B2B is shallow. Pricing tiers, account hierarchies, approvals, quotes and credit terms are where wholesale actually lives, and where platform support runs out first.
Your data model is Shopify's data model. Which matters more in 2026 than it did in 2022, for the reason below.
AI is why this got urgent
The AI that changes margin needs data you control.
Every merchant is being sold AI right now, and most of it is an app that rewrites product titles.
The AI that changes margin is different. Personalisation on real behaviour, pricing that responds to stock and demand, support that can see the order and act on it, forecasting that reads your actual sell-through. All of it needs two things: your data in a model you control, and the ability to write back into operations.
A hosted platform gives you neither, by design. That is not a criticism of Shopify, it is what hosting means. It is also why the interesting commerce engineering has moved to the layer above the platform. The store stays. The intelligence moves to where you own it.
What we build around Shopify
The layer that sits alongside your store.
Custom backends alongside your store.
Shopify keeps catalogue, checkout and payments. Your operational logic, the part that is actually your business, moves into a system you own and can change on your own schedule.
Real integration layers.
ERP, WMS, accounting, 3PL, CRM. Engineered integrations with error handling, retries and observability, rather than a chain of app-store connectors that fail quietly at 2am.
B2B and wholesale.
Pricing tiers, account hierarchies, approval flows, quotes and credit terms, built properly instead of approximated with tags and discount codes.
Headless and hybrid storefronts.
Where page speed or a differentiated buying experience is the actual competitive advantage, not a preference.
AI in operations.
Demand and stock forecasting, support with real order context, catalogue content generation, personalisation on first-party behaviour. Built on your data, deployed with evals before ship and monitoring after.
Migration to custom commerce.
When the platform genuinely stops paying for itself. Phased, with the store live throughout. We will tell you if you are not there yet.
Migrate off Shopify
Move off Shopify entirely and own a custom platform outright.
Not every team leaves because they have outgrown Shopify on the numbers. Some simply do not want to rent the core of their business. They want to own the whole stack, the data, the code, the roadmap and the release schedule, with no monthly Shopify dependency and no lock-in. Small or large, wanting to own your commerce platform outright is a legitimate reason to build custom, and it is the work we do best.
- Full ownership from day one. The complete codebase and infrastructure as code in your GitHub organisation, with full IP transfer and no licensed lock-in.
- A data model built around your business. Your commerce logic and customer records designed for how you operate, not shaped to fit Shopify's schema.
- A roadmap nobody can reprice or rate-limit. No platform plan, app tax or API quota deciding what you are allowed to ship next.
- A phased migration off Shopify. We move you to a custom commerce platform in stages, with the store live and selling the whole way through.
Equipp and Rensemble are custom commerce platforms we built and the teams own outright. If independence from the platform is the goal, that is exactly what we build. Tell us what you run on Shopify today and we will map the migration path.
Where to start
The fastest way to find your 20% is a conversation.
Shopify does a great deal well, and most teams should keep it doing exactly that. The value is in spotting the 20% that is quietly holding you back. It is usually one of these:
- the workflow your ops team keeps patching by hand every week
- the integration that breaks at 2am and nobody fully trusts
- the B2B or pricing logic you approximate with tags and discount codes
- the AI you cannot deploy because the data still belongs to the platform
Bring one of those to a 30-minute call and you will leave knowing exactly what to build, what it costs, and what it unlocks. That is the whole point of talking early.
What it costs
What custom Shopify work costs
The short answer
Custom engineering around a Shopify store at KUMO starts at $20K to $50K for a first build and runs $50K to $100K for multi-workflow platform work, with an optional engineering team on retainer after. We build the custom layer around your store, the systems, integrations and AI that become your advantage as you grow, while Shopify keeps running catalogue, checkout and payments. We do not build themes or set up stores; that is a different specialism, and we are glad to point you to the right partner for it.
Starter Build
$20K to $50K
4 to 16 weeks
A first custom system alongside your store: one integration, one operational workflow, or one B2B capability shipped end to end.
Grow Build
$50K to $100K
16 to 24 weeks
Multi-workflow platform work: custom backend, several engineered integrations, headless storefront, or a phased migration to custom commerce.
Support and Growth Team
$5K to $10K per month
Ongoing, cancel with 30 days notice
The engineering team on retainer once the layer is live: new integrations, AI model tuning, incidents, and the next capability.
These are the live custom software development bands, with the Shopify framing on each, no new numbers. Not sure which one you are? That is exactly what the first call is for.
Proof
Commerce platform engineering on live revenue systems.
Equipp (Ralco Group). A B2B and B2C rental marketplace for a 25-year IT hardware business: catalogue, payments and deposits, inventory engine, operations dashboard, reverse logistics. In the client's own Clutch review, the work included rebuilding the billing system from pro-rata to monthly and repairing a broken payment gateway integration. That is commerce platform engineering on a live revenue system, which is the same job as the escape work described above.
Read the case study →Rensemble. A designer fashion rental marketplace where customers rent high-end clothing and accessories by the occasion instead of buying. We built the shopper-facing experience and the engine behind it: catalogue and browsing by brand, category and occasion, size, colour and rental-period selection, checkout and payments, the security and fraud controls a rental model needs, transactional email across the rental lifecycle, and the operations dashboard the team runs the business from, from inventory and orders through to fulfilment and returns.
Visit the live marketplace ↗CampaignHQ. KUMO's own SaaS, built, run and operated by us. Email and WhatsApp customer engagement, which is precisely the channel layer commerce operators bolt onto a store. Live on G2 and Capterra, running on AWS.
Read the case study →Assembled per build
Technologies we build with.
There is no single KUMO stack. Every build gets its own, assembled for your workload, your data, your team, and whoever maintains the system after handover. These are the technologies we assemble those stacks from, and why each earns its place.
Languages and runtimes
- TypeScript
- Python
- Go
- Rust
- Node.js
- Bun
- Ruby on Rails
TypeScript end to end for most products: one language across frontend and API cuts handover cost and hiring risk. Python where the workload is AI-heavy. Go where raw throughput decides the architecture, and Rust on hot paths where every millisecond is money. We run Node.js and adopt Bun where its speed pays. Our engineers shipped and scaled Ruby on Rails at Volopay, and we still support Rails codebases in production.
Product surfaces
- React
- Next.js
- Astro
- React Native
- Expo
- Tailwind CSS
- shadcn/ui
- Radix UI
React and Next.js for web products. Astro for content-heavy sites where load speed is the feature. React Native with Expo for iOS and Android from one codebase, native modules where the product demands them. Tailwind CSS with shadcn/ui and Radix for design systems that ship fast. Real-time and streaming interfaces with WebSockets and server-sent events, because AI products that make users wait for a full response feel broken.
APIs, data, and architecture
- Convex
- Node.js
- Hono
- Postgres
- Drizzle
- Redis
- Zod
- Better Auth
- FastAPI
- Supabase
Two backend tracks, chosen per product. Convex for real-time serverless products: queries, mutations, actions, a scheduler, cron jobs, storage, and live subscriptions. Node.js services with Hono and typed oRPC over Postgres and Drizzle ORM for relational, retrieval-heavy products. Postgres is extended with pgvector for vector search and full-text search, so most AI features ship without a second database. Redis for caching and queues. Zod for end-to-end validation, Better Auth for authentication, and FastAPI or Supabase where they fit the job.
AI models
- OpenAI
- Anthropic
- Gemini
- Llama
- Mistral
- DeepSeek
- ElevenLabs
Model choice is an engineering decision, not a loyalty program. OpenAI GPT and Anthropic Claude for frontier reasoning, Google Gemini where multimodal or context length wins. Open-weight models, Llama, Mistral, DeepSeek, self-hosted when privacy or unit economics demand it. Specialist models where the product needs a specialist: ElevenLabs and dialogue-native TTS for production voice, Whisper for speech to text, dedicated embedding and reranking models for retrieval quality, image and vision models for documents and floor plans. Every model sits behind a provider-swappable abstraction, so switching is a configuration decision, not a rewrite.
AI application layer
- Vercel AI SDK
- Qdrant
- LangGraph
- Hugging Face
AI features are built on the Vercel AI SDK and Convex Agent and RAG components: structured outputs, agentic tool use, streaming, and embeddings. Retrieval on pgvector by default, with Cohere reranking and Tavily web-search fallback, and managed vector stores like Qdrant at scale. Orchestration with LangGraph or custom code, tool connectivity over MCP, the protocol now standardising how AI systems talk to software. And the part that decides whether AI survives production: evals before ship, tracing in production, structured outputs, semantic caching, and model routing to control cost.
AI infrastructure and GPU
- Ollama
- FFmpeg
We deploy AI through AWS Bedrock, Google Vertex AI, and Azure OpenAI where enterprise controls matter, direct APIs where speed matters, and vLLM or Ollama where self-hosting wins. Self-hosted GPU inference on RunPod with a scale-to-zero strategy, and image models through fal.ai. Media assembly and normalisation with FFmpeg.
Cloud, delivery, and jobs
- AWS
- Google Cloud
- Azure
- Docker
- Coolify
- Kubernetes
- Turborepo
- Terraform
- GitHub Actions
AWS first: KUMO is an AWS Partner and runs its own SaaS, CampaignHQ, on AWS in production, with S3, EC2, CloudFront, and Route 53. Also Google Cloud, Azure, and client infrastructure including on-prem. Docker everywhere, Coolify and Kubernetes for deployment, serverless and edge where they fit. Monorepos on Turborepo, infrastructure as code with Terraform, background jobs on Trigger.dev, and delivery through GitHub Actions CI/CD.
Observability and quality
- Sentry
- OpenTelemetry
- Playwright
Sentry for application errors, Langfuse for LLM traces, model metadata, and token usage, and OpenTelemetry for distributed tracing. End-to-end and AI-driven browser testing with Playwright. Cost, latency, and error tracking by workflow and model, so problems surface before customers see them.
Payments and integrations
- Stripe
- Razorpay
- Resend
- Discord
Billing and payments with Stripe and Razorpay, subscriptions, webhooks, tax, and invoicing. Transactional email through Resend, team workflows over Discord, and the Google ecosystem, OAuth, Drive, and Sheets, wired in where products need it.
FAQ
Custom Shopify development, answered straight.
How much does custom Shopify development cost? +
Custom engineering around a Shopify store starts at $20K to $50K for a first build, typically 4 to 16 weeks. Multi-workflow platform work runs $50K to $100K over 16 to 24 weeks. Ongoing engineering is $5K to $10K per month.
Do you build Shopify themes or set up stores? +
No, themes and store setup are a different specialism. What we build is the custom systems, integrations and AI around a store, the layer that becomes your advantage as you scale. If you also need a theme or a store launched, we are glad to point you to the right partner for it.
Is KUMO a Shopify Partner or Shopify Plus Partner? +
No. We are an AWS Partner and we build custom software and production AI. We work alongside Shopify rather than inside its partner programme, and we think you should know which one you are hiring.
Do we have to leave Shopify to work with you? +
Usually not, and we will normally advise against it. Most of what teams want, custom operations, real integrations, B2B logic, AI, can be built alongside the store while Shopify keeps handling catalogue, checkout and payments.
What is headless Shopify and do we need it? +
Headless means your storefront is a custom application that reads from Shopify through its APIs, so you control the experience while Shopify runs commerce underneath. You need it when page speed or a differentiated buying experience is genuinely a competitive advantage. You do not need it because it is fashionable, and it adds real maintenance cost.
Can an app do this instead? +
Sometimes, and when it can we will say so. Apps stop being the answer when you need custom business logic, when integrations must be reliable rather than best-effort, when several apps are fighting each other, or when the work needs data the app cannot reach.
How long does it take? +
A first custom build alongside your store is 4 to 16 weeks. A full multi-workflow platform is 16 to 24 weeks. Your store stays live throughout, on every engagement.
Who owns the code? +
You do, from day one. Source code, infrastructure as code, deploy configs and documentation, in your GitHub organisation. Full IP transfer, no licensed components, no lock-in to KUMO.
Can you migrate us off Shopify entirely? +
Yes, when the numbers support it, phased and with the store live throughout. We will also tell you when they do not. Migration is the most expensive answer to most of the problems people bring us, and it is the right one less often than you would think.
Do you work with WooCommerce or Magento? +
Yes. The same pattern applies: keep the platform doing what it does well, build the custom and AI layer around it, migrate only when the platform genuinely stops paying for itself.
Tell us where the platform is holding you back.
30 minutes, no deck. Describe what your team cannot do today, and we will tell you straight whether it is a Shopify configuration problem, an app problem, or an engineering problem. Three answers, and only one of them is us.