The verdict in three sentences
A replatforming is only justified when your current platform costs more to maintain than to replace, or when it stops you from selling. In 2026, budget 40,000 to 120,000 EUR and 4 to 8 months for a B2B store, with one major and often underestimated risk: a botched SEO migration can wipe out 20 to 40% of your organic traffic. The right call is made on the three-year TCO, not on the redesign price alone.
The signals that trigger a replatforming
A rebuild is not decided because the site "looks old". It is decided on measurable signals: rising running costs, functional ceiling, degraded performance. As long as none of these three axes is blocking, targeted optimization remains more profitable than a full rebuild.
| Trigger signal | 2026 alert threshold | Business impact |
|---|---|---|
| Annual maintenance cost | > 25% of rebuild cost | You fund a depreciating asset |
| Functional ceiling | No quotes, multi-buyer accounts, negotiated pricing | Lost B2B deals for lack of features |
| Performance (mobile LCP) | > 4 s | -1 to -3% conversion per second lost |
| Security / end of support | Vendor end-of-life version | Risk of unpatched vulnerability |
| Single-developer dependency | Only one vendor can maintain it | Risk of total lock-in |
| Time-to-market for changes | > 3 months for a simple feature | You lose to agile competitors |
If you tick three lines or more, replatforming becomes an investment decision, not a comfort one.
How much a B2B replatforming costs in 2026
The budget depends on B2B functional scope: multi-price catalogues, customer accounts with approval workflows, ERP integration, online quotes. Here are the 2026 orders of magnitude.
| Item | 2026 range (EUR) | Detail |
|---|---|---|
| Scoping & UX | 6,000 – 15,000 | Workshops, journeys, mockups |
| Platform development | 25,000 – 70,000 | Depending on B2B features and integrations |
| Data & SEO migration | 5,000 – 18,000 | Catalogue, customers, 301 redirects |
| ERP / PIM integration | 6,000 – 25,000 | Connectors, stock sync |
| QA & go-live | 4,000 – 12,000 | Testing, cutover, rollback plan |
| Project total | 40,000 – 120,000 | 4 to 8 month project |
One often-forgotten point: during the project, changes to the current site are frozen. This opportunity cost must enter your calculation.
Mini case study
Mark, e-commerce director of an industrial supplies distributor in London, runs a platform whose maintenance costs 32,000 EUR/year. Every change takes 4 months and the checkout funnel caps at 1.8% conversion. He quotes a replatforming at 78,000 EUR over 6 months.
His calculation: the new platform brings maintenance down to 14,000 EUR/year (-18,000/year) and targets 2.6% conversion. On online revenue of 3.2M EUR, that conversion gain is roughly +280,000 EUR annual revenue at a 22% margin, i.e. +61,000 EUR margin/year. Combining the run saving and the margin gain, the 78,000 EUR investment pays back in under 12 months — provided the SEO migration is not botched.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
How long does a B2B replatforming take in 2026?
Budget 4 to 8 months depending on the number of integrations (ERP, PIM, carriers). A simple scope without ERP fits in 4 months; a multi-price project with real-time stock sync often exceeds 7 months.
What is the real risk of a migration?
Loss of SEO traffic. Without a 301 redirect plan and preservation of strategic URLs, a rebuild can cost 20 to 40% of organic traffic for 3 to 6 months — a direct revenue drop.
Redesign or replatforming: what's the cost difference?
A graphic redesign on the existing stack costs 15,000 to 35,000 EUR. A replatforming (changing the technical stack) starts at 40,000 EUR because it includes migration, re-integration and full QA.
Can we avoid freezing features during the project?
Partially, by keeping a small corrective-maintenance budget on the old site. But any new feature built twice will need redoing: better to prioritize and freeze the rest.
How do we secure the budget before starting?
Require a paid scoping phase (5,000 to 10,000 EUR) that locks scope, integrations and the SEO migration plan before any development commitment. It is the best insurance against overruns.
Let's scope your project. Tell us about your current platform, order volume and ERP integrations, and we'll advise whether to optimize or replatform, with an indicative 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.