The verdict in three sentences
For a B2B SaaS vendor in Amsterdam with 340 pages and a 4.8 s mobile LCP, optimising WordPress for EUR 4,000 to 8,000 excl. VAT is enough if the problem is mainly images, theme and plugins. A migration to Next.js with a headless CMS at EUR 22,000 to 40,000 is justified when the site must evolve fast (product pages, documentation, segment landing pages) and the marketing team is blocked by the theme. Either way, a 301 redirect plan and Search Console monitoring at EUR 2,500 are non-negotiable, or you risk losing 10 to 30% of traffic.
Diagnosis: where does the 4.8 s LCP come from?
Measure before choosing. On a typical B2B SaaS WordPress site, poor mobile LCP has recurring causes: a heavy page builder, 30 to 50 plugins, uncompressed hero images, chat, analytics and A/B testing scripts loading as render-blocking, and shared hosting. A 3 to 5 day audit gives the answer: if 70% of the gain is reachable without changing architecture, optimisation is the right call.
| Option | 2026 budget (EUR excl. VAT) | Timeline | Expected mobile LCP | Limits |
|---|---|---|---|---|
| Performance audit only | 1,500 to 2,500 | 1 week | unchanged | Diagnosis, prioritised action plan |
| WordPress optimisation | 4,000 to 8,000 | 3 to 5 weeks | 2.6 to 3.2 s | Depends on theme and remaining plugins |
| New custom WordPress theme | 12,000 to 20,000 | 8 to 10 weeks | 2.2 to 2.8 s | Still tied to the plugin ecosystem |
| Next.js + headless CMS migration | 22,000 to 40,000 | 10 to 16 weeks | 1.2 to 2.0 s | Heavier investment, new tool for the team |
| 301 plan + Search Console monitoring | 2,500 | within schedule | n/a | Essential as soon as URLs change |
When a headless migration pays off
Migration is not only about speed. It makes sense when several conditions hold: marketing publishes more than 8 to 10 landing pages a month, product docs must be versioned, the site needs Dutch, German or French versions, or WordPress security causes incidents. A headless CMS (Sanity, Strapi, Payload) lets the team edit predefined blocks without breaking the design.
| Criterion | Stay on optimised WordPress | Migrate to headless Next.js |
|---|---|---|
| Landing pages per month | fewer than 5 | more than 8 |
| Languages | 1 | 2 or more |
| Product documentation | a few pages | hundreds of versioned pages |
| Security incidents in 12 months | none | 1 or more |
| LCP target | under 3 s acceptable | under 2.5 s on every page |
| Available budget | under EUR 10,000 | EUR 25,000 and above |
Protecting SEO during migration
On 340 pages, the main risk is forgotten URLs: old blog posts, renamed feature pages, indexed PDFs. The method: full URL export (crawl + Search Console + backlinks), one-to-one mapping table, 301 redirects tested on staging, preserved title tags and structured data, sitemap submission on launch day, then daily 404 monitoring for 30 days and weekly until day 90. With this plan, the temporary dip usually stays under 5% and recovers within 4 to 8 weeks.
Mini case study
Julian, marketing lead at an Amsterdam fleet management SaaS, gets 18,000 visits a month with a 1.2% demo conversion rate, or 216 requests. Average annual contract value is EUR 11,000 and 8% of demos sign: 17 customers a month from the site. If moving to a 1.8 s LCP lifts conversion by 15% (a 2026 order of magnitude seen on B2B sites), he gains about 32 demos and 2.6 customers a month. Over 12 months, that is close to EUR 340,000 in potential new annual contracts. A EUR 34,000 migration plus a EUR 2,500 SEO plan is absorbed within weeks, provided no traffic is lost.
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FAQ
Can we keep WordPress as the CMS with a Next.js front end?
Yes, headless WordPress via the REST API or WPGraphQL is a middle option at EUR 18,000 to 30,000. The team keeps its tool, but layout plugins no longer work.
How much traffic is lost during a migration?
With a complete 301 plan, the temporary dip usually stays under 5%. Without one, losses of 10 to 30% are common and can last several months.
How long does a 340-page migration take?
Plan 10 to 16 weeks: 2 weeks of scoping, 6 to 10 weeks of build and content migration, 2 to 4 weeks of testing and monitoring.
Can WordPress optimisation reach an LCP under 2.5 s?
Sometimes, if the theme is light and hosting is good. On page-builder themes, mobile LCP often plateaus between 2.6 and 3.2 s.
What does maintenance cost after migration?
A headless Next.js site costs EUR 250 to 600 excl. VAT per month for hosting, CMS and maintenance, versus EUR 150 to 400 for a well-maintained WordPress.
Let's scope your project. Send us your site URL and page count: we deliver an audit, then a quote comparing optimisation and migration, from EUR 4,000 to 40,000, with a 3 to 16 week plan. 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.
