The verdict in three sentences
A headless migration of a B2B store costs between EUR 30,000 and EUR 90,000 in 2026, depending on catalogue and integration complexity. The measurable gain: load time -40 to -60 percent and conversion +8 to +20 percent thanks to a fast decoupled front. The question to settle: does staying on a monolith (Shopify, Magento) suffice, or do performance and flexibility justify decoupling?
What the migration budget covers
Headless separates the front (Next.js) from the commerce back via an API. Here are the typical line items for a Berlin migration in 2026.
| Line item | 2026 range (EUR) | Timeline |
|---|---|---|
| Audit + target architecture | 3,000 - 9,000 | 2 - 3 weeks |
| Next.js front + design system | 12,000 - 35,000 | 6 - 12 weeks |
| Commerce API connection | 8,000 - 22,000 | 4 - 8 weeks |
| Catalogue migration + SEO | 4,000 - 14,000 | 3 - 6 weeks |
| Integration re-wiring (ERP, PIM) | 5,000 - 18,000 | 4 - 8 weeks |
| Perf testing + go-live | 3,000 - 10,000 | 2 - 4 weeks |
A targeted migration (front only) starts at EUR 30,000. A full rebuild with PIM and ERP exceeds EUR 80,000.
Stay monolith or go headless?
Headless is not always justified. Here is the 2026 trade-off in orders of magnitude.
| Criterion | Monolith (Shopify/Magento) | Headless (Next.js + API) |
|---|---|---|
| Switching cost | 0 (status quo) | 30,000 - 90,000 EUR |
| Load time | Baseline | -40 to -60 percent |
| B2B conversion | Baseline | +8 to +20 percent |
| Front flexibility | Limited (theme) | Total |
| Technical complexity | Low | High |
| Maintenance cost | Moderate | 12 - 18 percent of build/yr |
If your traffic is modest and your theme sufficient, stay on the monolith. Once performance and B2B experience become a conversion lever, headless pays off.
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Mini case study
Sophie, e-commerce lead of a pro-supplies distributor in Berlin, does EUR 4,200,000/year on her store with a 1.8 percent conversion and a 4.1 s load time. A headless migration at EUR 62,000 cuts load to 1.7 s and lifts conversion to 2.1 percent (+0.3 point). On the same traffic that is roughly EUR 700,000 additional revenue/year. Payback is estimated in under 4 months on margin, before SEO gains.
FAQ
How much is a B2B headless migration? Between EUR 30,000 and EUR 90,000 depending on scope. The Next.js front and ERP/PIM integration re-wiring are the heaviest items.
How much does performance improve? A well-designed decoupled front cuts load time by 40 to 60 percent, improving SEO and conversion, especially on mobile.
What conversion gain should we expect? In B2B, +8 to +20 percent is common after migration, thanks to speed and a smoother ordering experience. It is an estimate, to validate with A/B testing.
Can we keep Shopify or Magento as the back? Yes, and it is common: keep the commerce back and replace only the front via the commerce API. That reduces risk and cost.
What is the migration timeline? Between 4 and 8 months depending on catalogue and integrations. A gradual per-category rollout limits risk.
Let's scope your project. Give us your current platform, volume and integrations to estimate the conversion gain and budget. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.