The verdict in three sentences
Migrating from a monolithic WordPress to a headless / Next.js architecture typically costs 25,000 to 70,000 EUR excl. tax and runs 10 to 18 weeks depending on content volume and the number of templates. The payoff shows on three axes: performance (Core Web Vitals back in the green), security (reduced attack surface, no more exposed vulnerable plugins) and running cost (fewer incidents, more predictable hosting). If your site exceeds 500 pages, faces traffic spikes or carries your B2B reputation, the math almost always favors migration.
Cost per work package for a headless migration
A migration is not a single flat fee: it is a sequence of packages, each with its own risk and budget. Here is a 2026 order of magnitude for a mid-size B2B institutional site (300 to 800 pages).
| Package | Scope | 2026 cost (EUR excl. tax) | Timeline |
|---|---|---|---|
| Headless CMS | Sanity/Strapi setup, content models, roles | 6,000 - 14,000 | 2-3 wks |
| Next.js front | Design system, templates, App Router, ISR | 10,000 - 28,000 | 4-8 wks |
| Content migration | Import, cleanup, field mapping | 4,000 - 12,000 | 2-4 wks |
| 301 redirects | Redirect plan, testing, monitoring | 2,000 - 6,000 | 1-2 wks |
| QA & go-live | QA, perf, DNS cutover, rollback plan | 3,000 - 10,000 | 1-2 wks |
The most underestimated line is content migration: a ten-year-old WordPress accumulates inconsistent ACF fields, shortcodes and poorly organized media. Budgeting for cleanup avoids paying twice.
Performance and security gains
The real selling point to a leadership team is not the tech stack but the numbers after cutover. Here are the typical gains from a well-run headless move.
| Metric | Loaded WordPress | Headless Next.js | Effect |
|---|---|---|---|
| LCP (mobile) | 3.8 s | 1.4 s | -63% |
| Lighthouse perf score | 42 | 96 | +54 pts |
| Exposed plugins | 28 | 0 | Reduced surface |
| Security incidents / yr | 4-6 | 0-1 | -80% |
| Build/deploy time | manual, risky | CI/CD 5 min | Reliable |
| Hosting cost / yr | 2,400 EUR | 900 EUR | -62% |
With headless, the front ships as static pages or ISR: no PHP executed on every visit, so no classic WordPress exploit exposed. The back office stays isolated, often behind SSO.
Staying on optimized WordPress vs migrating: the 3-year math
| Item (3 years) | Optimized WordPress | Headless Next.js |
|---|---|---|
| Upfront investment | 8,000 EUR | 45,000 EUR |
| Maintenance/security | 18,000 EUR | 9,000 EUR |
| Hosting | 7,200 EUR | 2,700 EUR |
| Incidents & downtime | 12,000 EUR | 2,000 EUR |
| 3-year total | 45,200 EUR | 58,700 EUR |
| Perf & conversion | flat | +15-25% leads |
On paper optimized WordPress stays cheaper in cash, but it solves neither performance nor security risk, and it caps conversion. As soon as the site generates B2B leads, the conversion gap covers the migration premium.
Mini case study
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Thomas, digital lead at an industrial mid-cap in Lyon, runs a 640-page WordPress with 26 plugins. The site suffers 2 security incidents a year (roughly 6,000 EUR of cumulative remediation) and a 3.9 s mobile LCP dragging down SEO. He migrates to headless Next.js for 48,000 EUR excl. tax. After cutover, LCP drops to 1.3 s, organic traffic gains 18% in 6 months, and quote requests rise from 40 to 51 per month. At a 12,000 EUR average deal and an 8% close rate, those 11 extra monthly leads mean 10.5 new contracts/year — the migration pays back in under 5 months.
FAQ
How long does a headless migration take?
Expect 10 to 18 weeks depending on the number of templates and content volume. A 60-page brochure site migrates in 8 to 10 weeks; an 800-page multilingual site rather 16 to 20 weeks.
Will we lose our search rankings?
No, provided the 301 redirect plan is complete and tested before cutover. Done well, a headless move improves SEO through Core Web Vitals; allow a 4 to 8-week stabilization period.
Will our editors have to relearn everything?
The back office of a headless CMS like Sanity stays simple and often more pleasant than the WordPress editor. Plan 1 to 2 days of training, about 1,500 EUR excl. tax.
Can we migrate in stages rather than all at once?
Yes, a strategy by subdomains or sections allows a gradual cutover. It is slightly more expensive (+10 to 15%) but reduces risk for very large sites.
What hosting for a Next.js front?
Vercel, Netlify or a self-hosted Node runtime. For an institutional site, budget 900 to 1,500 EUR/year, roughly half a properly secured and backed-up WordPress.
Let's scope your project. Give us the page count, the languages and your performance targets, and we'll frame the migration scope 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.
