The verdict in three sentences
For a 180-page B2B WordPress site weighed down by 40 plugins and a 4.8 s LCP, migrating to headless Next.js costs 18,000 to 45,000 EUR in Amsterdam in 2026, for a 6 to 10 week project. The LCP improvement usually lands between 40 and 70 %, provided images, fonts and third-party scripts are handled alongside the technology switch. The real risk is not technical: it is losing SEO traffic if the 301 redirect plan does not cover 100 % of existing URLs.
What the migration costs, line by line
A headless migration separates content (managed in a CMS such as Sanity or Strapi) from presentation (Next.js). The budget mainly depends on the number of templates, the volume of content to migrate and the integrations (CRM, forms, customer portal). Dutch agency day rates are higher than in France, hence the higher range.
| Line item | 2026 market range in Amsterdam (EUR, excl. VAT) | Share of budget | Comment |
|---|---|---|---|
| Audit and URL inventory | 1,500 to 4,000 | 8 to 10 % | Full crawl, pages that drive traffic |
| Content modelling in the CMS | 2,200 to 6,000 | 12 to 14 % | Content types, fields, roles |
| Next.js development (8 to 15 templates) | 7,500 to 19,500 | 40 to 45 % | Components, static and incremental rendering |
| Migration of 180 pages and media | 2,300 to 6,500 | 12 to 15 % | Import script, image optimization |
| Integrations (CRM, forms, analytics) | 2,200 to 5,000 | 10 to 12 % | Replacing plugins |
| 301 redirect plan and SEO testing | 2,300 to 4,000 | 8 to 12 % | 100 % of URLs, checks before and after |
| Total | 18,000 to 45,000 | 100 % | 6 to 10 weeks |
The CMS choice drives recurring costs. Sanity is a managed service, free up to a certain volume then billed per user. Strapi is open source and self-hosted, which removes the license but adds a server to maintain.
Expected gains and recurring costs
Gains show up in Core Web Vitals, in security (a smaller attack surface than WordPress with 40 plugins) and in team time. Here are ballpark before and after figures for this kind of site.
| Metric | Current WordPress | Headless Next.js (ballpark) |
|---|---|---|
| Mobile LCP | 4.8 s | 1.4 to 2.9 s, a 40 to 70 % gain |
| Mobile Lighthouse performance score | 35 to 55 | 85 to 98 |
| Plugins or dependencies to update | 40 plugins | 10 to 20 packages tracked continuously |
| Monthly hosting | 30 to 80 EUR | 20 to 150 EUR (Vercel, Netlify or dedicated server) |
| CMS license | 0 to 300 EUR per year of premium plugins | 0 to 99 USD per month depending on the Sanity plan |
| Security incidents per year | 2 to 5 critical alerts | Close to zero on the front end |
Hosting stays modest, but beware of free plans: they cap bandwidth and serverless functions. For a B2B site with 20,000 to 50,000 visits per month, plan 20 to 50 EUR per month, and up to 150 EUR with a customer portal.
Protecting SEO during the migration
Export the full URL list from the sitemap, Search Console and a crawl. Map every old URL to its new destination, including PDFs and category pages. Test redirects in staging before the switch, then monitor Search Console for 8 weeks. Keep the title tags, meta descriptions and structured data of pages that bring traffic. A 5 to 15 % traffic dip for 2 to 4 weeks is common; anything beyond that signals a problem to fix.
Mini case study
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Sanne, CTO of a 90-person SaaS scale-up in Amsterdam, migrates her 180-page site for 32,000 EUR in 8 weeks. LCP drops from 4.8 s to 1.9 s. The site generated 60 demo requests per month at a 1.2 % conversion rate. Six months later the rate reaches 1.5 % on stable traffic, 15 extra requests per month. With a 10 % close rate and an average annual contract of 12,000 EUR, that is about 1.5 extra deals per month, nearly 18,000 EUR of annual recurring revenue added each month. The project pays back in under 2 months of new deals. The team also saves about 6 hours a month of plugin updates.
FAQ
How long does a WordPress to Next.js migration take?
Plan 6 to 10 weeks for 100 to 250 pages: 1 to 2 weeks of audit and modelling, 3 to 5 weeks of development, 2 to 3 weeks of migration and testing.
Sanity or Strapi for a B2B site?
Sanity suits teams that want a managed service and real-time collaborative editing. Strapi suits companies that want to host their own data and avoid per-user billing.
Will we lose SEO traffic?
A 5 to 15 % dip for 2 to 4 weeks is common, then traffic recovers and often grows thanks to better performance. Without 301 redirects on 100 % of URLs, the loss can exceed 30 %.
Will the marketing team still be able to edit the site?
Yes, a headless CMS provides an editing interface, previews before publishing and roles. Plan 1 to 2 training sessions.
Can we keep WordPress as a headless CMS?
It is possible and cuts cost by 20 to 30 %, but you keep WordPress maintenance and part of its vulnerabilities. It makes sense if your editors are strongly attached to it.
Let's scope your project. We run headless migrations with a URL audit, a complete redirect plan and quantified performance targets, with scope, indicative budget and schedule fixed in the quote. 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.
