Shopify vs custom Next.js — total 5-year cost breakdown for $5M+ GMV operators

The honest 5-year total cost comparison for a $5M GMV e-commerce operator scaling to $20M. Shopify Payments processing, Shopify Plus subscription, app stack, and theme limits vs custom Next.js + headless commerce. Real line items, real assumptions, no vendor-tilted math.

The two scenarios

Scenario: a $5M GMV operator in year 1, growing 30% YoY, hitting $20M+ GMV by year 5. Established catalog, mature operations, growing organic + paid traffic mix. Two platforms compared.

Scenario A — Shopify Plus

Assumptions and line items per year:

• Shopify Plus subscription: $2,300/mo at $5M GMV, scaling with revenue per Shopify Plus pricing tiers. Effective rate ~0.55% of GMV at higher tiers. At $5M, $27,600/year. At $20M, ~$110,000.
• Shopify Payments processing: 2.4–2.9% per transaction. Net of card brand fees, Shopify retains ~0.25–0.6%. On $5M GMV, ~$15k–$30k of Shopify margin alone (not the total processing cost, which is significantly higher).
• App stack: reviews, shipping, abandoned cart, advanced product options, subscriptions, custom checkout extensions, analytics, search, recommendations. Typical app spend at this scale: $3,000–$10,000/month. Year 1: $60k. Scales modestly with growth: $80k by year 5.
• Custom theme development: $30k–$80k one-time for a custom Plus theme. Add $15k–$30k/year for ongoing theme + CRO work.
• Engineering team: 1 senior engineer for ongoing Liquid + app integration work, ~$120k–$180k/year fully loaded.

Year-by-year totals for Scenario A:

• Year 1 ($5M GMV): $27.6k subscription + $25k Shopify Payments margin + $60k apps + $50k theme + $150k engineer = $312,600
• Year 2 ($6.5M GMV): $36k + $32k + $65k + $20k + $160k = $313,000
• Year 3 ($8.5M GMV): $47k + $42k + $70k + $20k + $170k = $349,000
• Year 4 ($11M GMV): $61k + $55k + $75k + $20k + $175k = $386,000
• Year 5 ($20M GMV): $110k + $100k + $80k + $20k + $180k = $490,000

5-year total Shopify Plus: ~$1.85M

Scenario B — Custom Next.js + headless commerce

Same operator, custom platform built once, ongoing retainer:

• Initial build: $120k one-time (Next.js storefront + headless commerce backend + custom checkout + payment integration + custom POS for the physical retail side). See our e-commerce development service for engagement shapes.
• Migration from Shopify: $20k–$30k for data migration + 301 redirect map + parallel run. Included in year-1 cost.
• Ongoing platform retainer: $80k–$120k/year (infrastructure, feature releases, conversion optimization, A/B testing, security). Year 1: $100k. Modest growth annually.
• Payment processing: 1.5–2.9% via direct Stripe / Square / Adyen integration. No Shopify markup. Same processor fees as Shopify Plus, just without the layered Shopify margin.
• App / service stack: $1,500–$3,000/month for the equivalent functionality (reviews, email, analytics, search). Many Shopify apps replaced by direct integrations included in retainer. Net year 1: $20k–$30k.

Year-by-year totals for Scenario B:

• Year 1 ($5M): $150k build + $100k retainer + $0 platform fees + $25k apps = $275,000
• Year 2 ($6.5M): $0 + $105k + $0 + $25k = $130,000
• Year 3 ($8.5M): $0 + $110k + $0 + $28k = $138,000
• Year 4 ($11M): $0 + $115k + $0 + $30k = $145,000
• Year 5 ($20M): $0 + $120k + $0 + $35k = $155,000

5-year total custom Next.js: ~$843,000

The headline number

5-year delta: ~$1M saved on the custom platform path. Payback hits in year 2. By year 5, custom is running at less than one-third the annual cost of Shopify Plus.

What this comparison ignores

The pure dollar math is one part. Three uncounted variables:

1. Conversion rate from custom checkout

Custom checkout typically lifts conversion 5–15% vs Shopify standard checkout. On $5M GMV, a 7% conversion lift is $350,000 in incremental year-one revenue. On $20M, $1.4M. This is the single biggest uncounted variable and frequently the actual reason operators switch.

2. SEO compound effect

Custom Next.js stores typically rank better long-term because the platform-layer SEO fixes that are constrained on Shopify (faceted-navigation crawl control, full schema flexibility, Core Web Vitals) ship clean. Over 5 years, 15–30% more organic traffic is a reasonable expectation. We covered the schema side in our product schema for e-commerce post.

3. Operational velocity

Custom platforms let operations ship workflow changes (custom B2B portals, subscription models, custom product configurators) within sprint cycles. On Shopify Plus, the same changes require app identification + integration + workarounds, often 3–6× the time. The compounding velocity advantage is real but hard to put a dollar number on.

What this comparison overcounts on the custom side

Honest disclosure — three places custom is harder than the dollar math suggests:

1. Build risk

Custom platform builds run over budget ~30% of the time across the industry. Our engagements run hot or cold but the average is roughly on-budget with 15–25% scope creep. Operators new to engineering engagements should treat the $120k build estimate as floor.

2. Vendor dependency risk

Custom platforms depend on the engineering partner staying in business + maintaining capability. If your partner shuts down, you have a custom codebase to maintain or migrate. We address this by transferring full code ownership + documentation + deployment infrastructure at every engagement's end. But the risk is real and Shopify removes it.

3. Team adoption

Shopify has more documentation, more Shopify Partners, more freelancers, more YouTube tutorials. Custom platforms require operator team training + intentional onboarding. The first 6 months on a new custom platform are noisier than the first 6 months on Shopify.

When the math flips against custom

Custom doesn't always win. The math flips back to Shopify in these scenarios:

• Under $3M GMV: build cost amortization stretches too long. Shopify or Shopify Plus wins.
• Stagnant operations: if GMV isn't growing, the per-transaction-fee delta doesn't compound.
• No intention to invest in conversion / SEO / operational velocity: custom advantage is uncaptured if the team doesn't exploit the flexibility.
• Acquisition target within 24 months: custom codebase becomes due-diligence overhead for the acquirer. Shopify is faster to onboard the new owner.

The middle path — Shopify Hydrogen

Shopify Hydrogen lets you keep Shopify Plus (catalog + checkout) but build the frontend in custom Next.js / React. Roughly: $80k–$120k one-time storefront build + Shopify Plus subscription + reduced app spend (most Shopify apps replaced by custom frontend logic). 5-year cost typically ~$1.2M — middle path between full Shopify Plus and full custom. Covered in our Shopify alternative page.

Real example — CBM Computers Karachi

We shipped this migration for CBM Computers — premium electronics retailer in Karachi running on a generic Shopify theme. Three workstreams in one engagement: custom AI-powered POS + custom Next.js storefront replacing the Shopify theme + end-to-end SEO targeting Pakistani buyer queries. Page-speed improved 3–5×, green Core Web Vitals across mobile + desktop, schema-rich product pages. Full case study at CBM Computers case study.

FAQ

What about the Shopify ecosystem we depend on?

Every major Shopify app has an equivalent — sometimes direct API replacement, sometimes a different vendor, occasionally rebuilt as a feature of the custom platform. Migration assessment phase identifies every dependency before committing to build.

Will we lose SEO during migration?

Not if migration is done right. 301 redirect map preserves every product URL. Schema typically improves. Core Web Vitals usually improve substantially. SEO equity preserved, often amplified.

How long does migration take?

Starter custom platform: 12–16 weeks. Full custom with complex requirements: 4–6 months. Migration data + parallel run + cutover: 2–4 weeks of that timeline. Total kick-off to live: 16–28 weeks with no customer-visible downtime.

Do we own the code at the end?

Yes. Full source code, database, deployment infrastructure, documentation, knowledge transfer to your team or designated successor. Code ownership is the foundational difference between custom and SaaS.

Next steps

Run the math for your specific GMV trajectory. If 5-year savings exceed $500k, the custom case is strong. Read when to leave Shopify for the qualitative signals. Talk to us about a Shopify alternative engagement or full custom e-commerce platform when ready.