The verdict in three sentences
A successful institutional website migration rests on three pillars: an exhaustive 301 mapping from old URL to new, a content freeze during cutover, and staging QA before go-live. The 2026 budget is between 4,000 and 12,000 EUR (about 4,300-13,000 USD) for 400 pages, over 4 to 8 weeks. The risk is not technical but organizational: one forgotten redirect means lost traffic and rankings.
The 2026 migration checklist
A digital lead migrating 400 pages must follow a strict sequence. Every skipped step raises the risk of a traffic drop in the weeks after cutover.
| Step | Key action | Risk if skipped |
|---|---|---|
| 1. Crawl the existing site | Full URL inventory | Orphan pages not redirected |
| 2. 301 mapping | Old URL -> new URL | Lost rankings and traffic |
| 3. Content freeze | Stop edits during cutover | Inconsistencies and duplicates |
| 4. Staging QA | Tests on a mirror environment | Bugs found in production |
| 5. Sitemap & robots | New sitemap submitted to Search Console | Slow indexing |
| 6. Post-migration tracking | Monitoring 30-90 days | Undetected drop |
The 301 mapping is the heart of the job: every indexed old URL must point to the closest equivalent, with no redirect chains. Mass 404 errors are the first sign of a failed migration.
KPIs to watch and risk fixes
A migration is steered by data. You compare before and after over a rolling window to separate a migration effect from a seasonal variation.
| KPI | Before migration | Target after 60 days |
|---|---|---|
| Organic traffic | Base 100 | 95-105 (back to normal) |
| Indexed pages | e.g. 400 | 380-400 |
| 404 errors | Low | Close to zero |
| Core Web Vitals (LCP) | 3.2 s | < 2.5 s |
| Top 10 rankings | e.g. 120 keywords | Maintained +/- 10% |
| Server response time | 600 ms | < 300 ms |
Main fix: keep the old site readable for 30 days, retain crawl logs and check Search Console daily in the first week. An organic traffic drop above 20% demands an immediate review of the 301 mapping.
Mini case study
Sarah, digital lead of a cultural institution in Singapore, migrates a 400-page site to a headless stack. Quote: 8,500 EUR (mapping, QA, 90-day tracking). Her organic traffic is about 40,000 visits/month, driving 15% of event sign-ups.
A 25% traffic loss over 3 months would have cost roughly 30,000 visits and a measurable drop in sign-ups. By investing in rigorous 301 mapping and staging QA, her migration ended with traffic stable within +/- 4% and LCP improving from 3.1 s to 1.9 s by the second week.
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FAQ
How long before traffic recovers after migration?
Usually 4 to 8 weeks with clean 301 mapping, sometimes up to 3 months for a large site. A temporary 5 to 15% dip in the first two weeks is normal and recovers.
Should you keep the old URLs?
No, but every indexed old URL must be 301-redirected to its equivalent. Avoid redirect chains and mass redirects to the homepage.
What is the main migration risk?
Forgotten or mis-targeted redirects that generate 404s and lose rankings. A full before/after crawl is the best insurance.
Can you migrate without a content freeze?
It is not advised: editing content during cutover creates inconsistencies and complicates diagnosis if traffic drops. A freeze of a few days is usually enough.
What does a 400-page migration cost?
Between 4,000 and 12,000 EUR in 2026 depending on mapping complexity, CMS and tracking duration. The 90-day tracking is the best investment.
Let's scope your project. Give us the URL count, current and target CMS, and your deadline, and we will frame the migration (4,000-12,000 EUR) with no SEO loss. 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.
