Headless CMS Migration: When Sanity, Next.js, and Vercel Make Sense

"Headless" has gone from buzzword to default for a certain kind of company. But migrating a live site is a real project with real risk, so the question isn't can you go headless, it's should you, and when.

What "headless" actually means

A traditional CMS like WordPress couples content and presentation: the same system stores your posts and renders your pages. A headless CMS only stores and serves content (via an API). A separate front-end, usually a framework like Next.js, decides how it looks. The "head" (the front-end) is decoupled from the "body" (the content).

Signals it's time to migrate

• Your site is slow and plugin bloat is fighting your Core Web Vitals.
• You publish to multiple channels (web, app, email) and want one content source.
• Editors and developers keep stepping on each other in one system.
• Security and maintenance overhead is eating your team's time.

If none of these hurt, you probably don't need to migrate yet. Headless is a tool, not a trophy.

The Sanity + Next.js + Vercel stack

Each piece does one job well:

• Sanity, a flexible, real-time headless CMS. Editors get a customisable studio; developers get structured, queryable content.
• Next.js, renders fast, SEO-friendly pages from Sanity's data, statically or on the edge.
• Vercel, deploys and serves it globally with previews, instant rollbacks and near-zero ops.

Together they give editors a clean writing experience and visitors a site that loads in a blink.

What it costs

A migration is not a like-for-like swap; you're rebuilding the front-end. For a typical marketing site, budget for design/build of the new front-end plus content modelling in Sanity. The upside is that ongoing hosting and maintenance costs usually drop afterwards, and speed gains often pay for the project in conversions and rankings.

A safe migration plan

1. Audit & inventory. Catalogue every URL, template and content type on the current site.
2. Model content in Sanity. Design schemas that match how your team actually writes.
3. Rebuild the front-end in Next.js. Match URLs exactly to preserve SEO.
4. Migrate content. Script the import so nothing is lost or mangled.
5. Preserve SEO. Keep URLs identical where possible; 301-redirect anything that changes; re-submit your sitemap.
6. Launch behind a preview, then flip DNS. Test on a staging URL, then cut over with rollbacks ready.

Do this carefully and visitors won't notice anything except a faster site, which is exactly the point.