Importing Content From Another CMS Into WordPress: What Breaks and What Survives

Half my “WordPress migrations” are not hosting moves at all — they are platform exits. Squarespace to WordPress, Wix to WordPress, Ghost to WordPress, or escaping some long-dead CMS a previous agency built. These moves fail differently than server migrations: the hosting is fine, but the content arrives mangled. Here is what I have learned about what survives the journey and what needs a plan.

What survives an import almost every time

• Body text and headings. Paragraphs and H2/H3 structure map cleanly into WordPress.
• Images, if you export them. Never rely on the importer to fetch remote images — some do, some half-do, and hotlinked images break the day the old site expires. Download everything and re-upload.
• Basic metadata. Titles, slugs, and publish dates usually translate, and preserving the original slugs is the whole SEO game here.

What reliably breaks

• Custom styling. Squarespace blocks and Wix sections are design objects, not HTML. Expect to rebuild layouts in the WordPress editor or blocks. Budget for it — this is the real cost of platform exits.
• URL structures. Wix and Squarespace use paths like /blog/post-name or /post-name-1. If your WordPress permalinks do not match, every URL needs a 301 redirect map. This is non-negotiable; see my post-migration SEO checklist for the redirect testing routine.
• Comments, tags, and internal links. Internal links written as full old-domain URLs rot into the new site. Run a search-replace on the imported content for the old domain — but do it with a database-safe tool, not a naive find-replace that corrupts serialized data.
• Forms and e-commerce. Form submissions, customer records, and order history rarely import cleanly. Export them as CSV archives even if you never migrate them live; the archive is the fallback.

The import order that saves you

Platform exits go wrong when people import first and plan after. My order:

1. Export everything first, in the rawest format the old platform allows, before you touch anything else. Squarespace exports WordPress-format XML; Wix mostly gives you content via public pages; Ghost exports clean JSON. Whatever you get, archive it — the export is your rollback plan, the same principle as any migration rollback plan.
2. Build the URL map before importing. Old URL → new URL, as a spreadsheet, for every page you care about. You will convert this into redirects.
3. Import on staging and fix formatting there. Never import into a live site, even for “just a test.”
4. Spot-check 20 pages: formatting, images, internal links, and metadata. Importers are 90% right and that last 10% is always on your most-visited pages.
5. Ship with redirects configured, then verify live with the same routine I use after any site migration.

Is it worth it? Sometimes the answer is no

A platform exit is also the moment to ask whether the content deserves a fresh start. If the old site has 30 posts and 12 get traffic, I would rather import the 12 properly than drag all 30 over with broken layouts. The rest can redirect to the closest new page or be archived. Less content, migrated well, beats more content, migrated badly — the same math as deciding between a hosting migration and a rebuild.

And one honest caveat: exporters are imperfect. If your source platform gives you a bad export, scraping your own live pages into HTML files and importing those is a legitimate, unglamorous fallback. I have done it more than once and the result was cleaner than the official tool’s output.