The verdict in three sentences
A WordPress-to-headless migration (Next.js + a CMS like Sanity/Strapi) costs between 20,000 and 55,000 EUR (excl. VAT) in 2026, over a timeline of 8 to 16 weeks. The main gain is performance: -40 to -70 % on LCP, which improves SEO and conversion. The risk to control is the 301 redirect map: done right it preserves rankings; botched, it drops traffic 30 to 50 %.
WordPress vs headless: what really changes
WordPress is still excellent for simple content, but a SaaS SME capping out on performance and security wins by going headless. Here is the comparison on the criteria that matter to a CTO.
| Criterion | Classic WordPress | Headless (Next.js + CMS) |
|---|---|---|
| Median LCP | 3.5 - 5 s | 1.2 - 2.2 s |
| Attack surface | Many plugins, PHP | Reduced, isolated API |
| Security incidents/yr | 4 - 10 (estimate) | 0 - 2 (estimate) |
| Hosting cost/mo | 40 - 150 EUR | 20 - 120 EUR (Vercel/Scaleway) |
| Traffic scalability | Limited, heavy cache | Native (edge, CDN) |
| Build cost | 8,000 - 20,000 EUR | 20,000 - 55,000 EUR |
The upfront headless premium is justified by lasting performance, fewer incidents and a better editorial experience once the CMS is modeled.
Roadmap and migration budget
A successful migration follows a strict sequence, because the SEO cutover cannot be replayed. Here is the typical roadmap of a 35,000 EUR project.
| Phase | Deliverable | Budget share | Timeline |
|---|---|---|---|
| Audit & URL mapping | URL, content, traffic inventory | 10 % | 1 - 2 wks |
| CMS modeling | Content schemas, data migration | 18 % | 2 wks |
| Front-end dev | Next.js, components, responsive | 34 % | 3 - 5 wks |
| 301 redirect map | URL-by-URL mapping, tests | 12 % | 1 wk |
| Performance & SEO | Core Web Vitals, schema, sitemap | 12 % | 1 - 2 wks |
| QA & cutover | Testing, post-launch monitoring | 14 % | 1 - 2 wks |
The 301 redirect map is the cornerstone: every old indexed URL must point to its new destination, otherwise Google loses the link structure and organic traffic collapses the following month.
Mini case study
Julien, CTO of a SaaS SME in Nantes, suffers 6 security incidents a year on WordPress and a 4.3 s LCP. He migrates to headless for 35,000 EUR. After cutover, LCP drops to 1.6 s (-63 %) and incidents fall to 1 a year. Each incident cost him roughly 1,200 EUR (dev time + downtime); the saving is ~6,000 EUR/year. Add the SEO gain: with LCP under 2.5 s, organic traffic rises ~18 % in 6 months, i.e. full ROI in under 18 months.
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FAQ
Will I lose my rankings when migrating?
No, if the 301 redirect map is exhaustive, URL by URL. We map every indexed page before cutover and monitor indexing for 4 to 6 weeks after. It is the most critical phase of the project.
How long does a headless migration take?
Between 8 and 16 weeks depending on content volume and integrations. Audit and CMS modeling take the first third, development the second, QA and cutover the last.
Will my editors be lost with a new CMS?
No, a modern headless CMS (Sanity, Strapi) offers a clean editing interface, often simpler than Gutenberg. We budget 1 to 2 training sessions in the QA phase.
What hosting for headless?
Vercel or Scaleway (EU sovereignty) depending on your GDPR constraints. Budget 20 to 120 EUR/month by traffic, often less than a performant managed WordPress with cache and security.
Can I keep WordPress only as a back office?
Yes, that is the headless WordPress approach: keep WordPress as CMS via its REST API and render with Next.js. It is a cheaper option (20,000-30,000 EUR) if your editors are attached to the tool.
Let's scope your project. Share your indexed URL count, integrations and an indicative budget, and we'll send back a costed migration roadmap. 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.
