Every quote you get for a Shopify Plus build will look different, because every agency scopes differently. This is a transparent breakdown of what an ecommerce agency actually costs in 2026, across theme builds, headless, migrations, and ongoing retainers, so you can sanity-check a quote before you sign it.
If you're comparing options, our Shopify Plus pricing calculator gives you a fast estimate specific to your revenue and platform fee tier.
Why agency quotes vary so much
Ask five ecommerce agencies to quote the same brief and you'll get five different numbers, sometimes 2-3x apart. That's not necessarily one agency price-gouging and another underselling. It usually comes down to four things: how much of the work is custom development versus configuration, how many integrations are in scope, whether design is bespoke or templated, and how much of the post-launch period is included in the price.
The numbers below are ranges we see across the market for mid-market brands doing $5M-$100M in revenue, not just what we charge. Use them to sanity-check a quote, not as a fixed price list - your actual number depends on your specific catalogue, integrations, and design scope.
Custom Shopify and Shopify Plus builds
A custom-built Shopify store (non-Plus, for brands under roughly $1M in annual revenue) typically runs $20K-$80K. That covers a custom theme or heavily customised foundation, standard integrations, and a clean, from-scratch build rather than a page-builder template.
A full Shopify Plus theme build typically runs $60K-$150K. The jump from standard Shopify reflects the platform's added capability - checkout extensibility, B2B, multi-market - and the more complex integration work that usually comes with brands at that revenue tier.
What moves the number within each range: integration count matters more than catalogue size above roughly 1,000 SKUs, since the mapping and QA work is largely fixed regardless of product volume. A brand with four integrations will cost meaningfully less than one with twelve, even at similar catalogue size.
Headless Hydrogen builds
A headless Shopify Plus build on Hydrogen, Sanity and Algolia typically runs $80K-$150K+ - roughly 2-3x a theme build, because you're commissioning a custom application rather than configuring a template. Complex multi-region or highly bespoke builds can run to $400K.
A rough breakdown for a mid-range $120K headless build: discovery and strategy $8K-$12K, design $25K-$35K, frontend development $30K-$45K, backend and integrations $15K-$25K, QA and launch $5K-$10K.
Headless also carries a different ongoing cost profile than themes - SaaS stack additions of $500-$2,000/month and a development retainer of $3K-$8K/month versus $1K-$3K for theme stores, since structural changes need a developer rather than the Shopify editor. We've covered this in full in the real cost of going headless.
Platform migrations
Migrating to Shopify Plus from Magento, BigCommerce, Salesforce Commerce Cloud or a custom platform is its own cost category, separate from a fresh build. A typical mid-market brand running a clean migration spends $225K-$600K in year one, covering the audit, build, a post-launch retainer for around six months, app stack, and integration tooling - excluding platform licence and payment processing. Year two settles to roughly $80K-$230K excluding licence.
Timeline tracks complexity more than cost does: WooCommerce and BigCommerce migrations typically run 8-14 weeks, Magento and Adobe Commerce 12-20 weeks, SAP and Oracle 16-24 weeks. The full breakdown, including what commonly blows the budget, is in our migration guide.
Ongoing retainers and support
Most brands move to a monthly retainer after launch for feature development, optimisation, and support. Theme-based stores typically run $1K-$3K/month. Headless stores typically run $3K-$8K/month, reflecting the developer dependency for structural changes that theme editors handle without one.
Retainer scope varies - some cover bug fixes and maintenance only, others include ongoing feature development and conversion testing. Clarify what's included before comparing two retainer quotes, since a cheaper monthly rate with a narrower scope isn't necessarily better value.
What actually moves the price
Four factors explain most of the variance between quotes for otherwise similar projects.
Integration count. Each integration - ERP, 3PL, email platform, reviews, loyalty - is a connector to build, test and maintain. This scales cost more directly than catalogue size does.
Design scope. A templated build with light customisation costs meaningfully less than a fully bespoke design system. Most Shopify Plus projects include a redesign because the old platform constrained the previous one.
Custom development versus apps. Most brands enter a migration or rebuild with 30-50 apps installed and exit with 12-20, trading recurring app fees for upfront custom development. That trade-off shows up in the quote.
What's included post-launch. A quote that excludes 30-90 days of post-launch support looks cheaper on paper but often costs more in practice once the gaps surface.
How to read a quote
A properly scoped quote follows a real audit - reviewing your current data, integrations, and traffic - not a guess from a discovery call alone. Quotes written without seeing that detail are typically 30-50% off reality once the real scope surfaces mid-project.
Ask what's included in the number: does it cover QA, does it include a defined post-launch support window, and is the integration list final or assumed. The agencies worth working with will walk you through the breakdown rather than handing over a single line-item total.
Where to start
For a fast, revenue-specific estimate, run your numbers through our Shopify Plus pricing calculator. If you're ready to scope an actual project, talk to our team - we'll walk you through a real estimate before any proposal goes out.
How much does a Shopify Plus agency cost?
A full Shopify Plus theme build typically costs $60K-$150K. A headless Hydrogen build typically costs $80K-$150K+, sometimes running to $400K for complex multi-region builds. A platform migration with integrations typically costs $225K-$600K in year one.
How much does a custom Shopify website design company charge?
A custom-built Shopify store for brands under roughly $1M in annual revenue typically costs $20K-$80K. This covers a custom theme or heavily customised foundation with standard integrations, rather than a page-builder template.
Why do Shopify Plus agency quotes vary so much?
Quotes vary based on how much of the work is custom development versus configuration, how many integrations are in scope, whether design is bespoke or templated, and how much post-launch support is included. Integration count typically moves the price more than catalogue size does.
What does an ongoing Shopify Plus retainer cost?
Theme-based stores typically run $1K-$3K per month for ongoing development and support. Headless stores typically run $3K-$8K per month, reflecting the developer dependency for structural changes that a theme editor handles without one.
Is the cheapest Shopify Plus quote the best value?
Not usually. Quotes written without a proper audit of your data, integrations, and traffic are typically 30-50% off reality once the real scope surfaces mid-project. A quote that excludes post-launch support looks cheaper upfront but often costs more once gaps surface after launch.
Does catalogue size determine Shopify Plus build cost?
Less than most brands expect. Above roughly 1,000 SKUs, the mapping and QA work is largely fixed regardless of catalogue size. Integration count and design scope move the price more directly than product count does.
Flux is a Shopify Plus Agency for AI Search, Design & Engineering
- A custom Shopify build (non-Plus) typically costs $20K-$80K. A full Shopify Plus theme build typically costs $60K-$150K.
- A headless Hydrogen build typically costs $80K-$150K+, sometimes running to $400K for complex multi-region builds.
- A platform migration with integrations typically costs $225K-$600K in year one, including build, audit, and post-launch support - separate from platform licence fees.
- Ongoing retainers run $1K-$3K/month for theme-based stores and $3K-$8K/month for headless stores that need developer support for structural changes.
- Catalogue size matters less than people think above 1,000 SKUs. Integration count and design scope move the number more than product count does.
- The cheapest quote is rarely the cheapest project. Scope gaps discovered mid-build cost more than the same work priced in from the start.
