Four kinds, with different risk
- Platform: same URLs, new system. Lowest risk if the URLs really do not change
- Structure: same platform, new URLs. Risk sits entirely in the redirect map
- Domain: everything moves. Needs a change of address and patience
- Consolidation: several sites into one. The hardest, and the most valuable when it works
| Type | What changes | Main risk |
|---|---|---|
| Platform | The system, not the URLs | Metadata and templates dropped in the rebuild |
| Structure | The URLs | Gaps in the redirect map |
| Domain | Everything | Slow reprocessing and missed change of address |
| Consolidation | Several sites into one | Competing signals and the largest mapping job |
What actually goes wrong
Not the build. The failures are a redirect map with gaps, a staging site left indexable, metadata dropped in the rebuild, and internal links still pointing at old URLs through a chain of hops.
Almost all of it is preventable by crawling the old site before anything changes and treating that crawl as the contract the new site has to satisfy.
What good looks like
On an Energo-Pro consolidation we merged three sites into one, migrating 1,262 pages across two languages with no loss of search visibility. On Juma we moved 216 pages off WordPress in 40 days, also with none. In both cases the work was in the inventory and the verification, not the design.
Why it matters for B2B marketing teams
The question a B2B marketing team should ask a prospective agency is not how the new site will look. It is what happens to the 200 URLs that currently bring in traffic. An agency without a clear answer is quoting for a design project, not a migration.