Rebuilding or migrating a website with Claude Code: what it involves

Rebuilding a website with Claude Code means using Anthropic's coding agent to do the heavy, repetitive engineering of a migration (crawling the old site, converting pages, writing redirects, applying site-wide fixes and running checks) while people decide what the new site should be, approve every deploy and own the facts. It can make a large migration practical for a small team. It does not remove the need for an inventory, a redirect map, an SEO parity check and careful QA.

It makes sense when the site is large enough that hand migration would be slow, when the content can be exported or crawled, and when someone can review what Claude Code produces. It makes less sense for a small site that a page builder could recreate in a day, or when no one on the team can read a diff or check a staging site.

We rebuilt eseospace.com this way in 2026, moving about 2,227 URLs off WordPress. This guide covers the steps, the risks and what we learned, with figures from our own site only.

When a rebuild with Claude Code makes sense

If you are moving off a builder or a platform, our guide to moving from WordPress to an AI-built website covers the platform-specific side, and our article on using Claude Code on WordPress explains what can and can't be done while you're still on WordPress.

Step 1: inventory everything

Before any code is written, list every URL and asset the old site serves. Claude Code can write the crawler, but a person should check the list against other sources.

• Every page, post, category, tag, author and media URL.
• Titles, meta descriptions, canonicals, robots directives, H1s and structured-data types for each page.
• Forms, popups, embeds, tracking scripts and where each sends data.
• Existing redirects, so you don't break old chains.
• Pages that get traffic or links, from your analytics and Search Console.

Our own rebuild covered roughly 1,650 posts, about 220 pages and about 300 portfolio entries.

Step 2: make the big decisions as people

These choices shape everything else, and they belong to you, not to the agent:

1. Fidelity or a fresh design. Will the new site look and behave like the old one, or be redesigned?
2. Platform and host. Static build, a framework such as Next.js, or another CMS.
3. URL structure. Keep URLs wherever possible; every change needs a redirect.
4. What to drop. Thin or outdated pages may be merged or retired, with redirects to the closest match.
5. Who approves deploys and how.

On eseospace.com, the first attempt was a clean Next.js rebuild that stripped out the theme's JavaScript. It broke animations, accordions, widgets and menus, and we abandoned it on day one. A person decided to keep the theme's own JavaScript and favor fidelity over clean code. That one decision changed the whole project.

Step 3: build on a copy, in git

Do all the work in a git repository, on a branch, against a staging copy. Give Claude Code a way to check its own work: Anthropic's best practices for Claude Code start with "Give Claude a check it can run: tests, a build, a screenshot to compare." Use plan mode for anything large, so you can approve the approach before files change.

On our rebuild, Claude Code wrote the crawler, the publishing pipeline, the deploy steps and the form function, and applied site-wide edits. By the end of September 2026 the project had 496 commits and 262 small build and fix scripts. Small, single-purpose scripts are easier to review and rerun than one large one.

Keep a separate copy of the old site until well after launch. Anthropic's checkpointing docs note that rewinding doesn't cover files changed by shell commands, and its overview of how Claude Code works adds that actions on remote systems such as deployments can't be checkpointed, so git and backups are your real undo.

Step 4: write and test the redirect map

Every old URL that changes needs a permanent redirect to its closest new equivalent. Google's site move guidance recommends "HTTP permanent redirects if possible, such as 301 and 308," says "301 and other permanent redirects don't cause a loss in PageRank," and advises keeping them "generally at least 1 year."

• Map one to one where you can; avoid sending everything to the homepage.
• Avoid chains (A to B to C); point old URLs straight at the final page.
• Have Claude Code test every rule against the staging site and report any that don't return the expected status and destination.

Our site ended September 2026 with 235 redirect rules in a single redirects file. Our guide to building a 301 redirect map covers the method in detail.

Step 5: run an SEO parity check

A parity check compares the old and new versions of each page on the things search engines read. On eseospace.com we compared titles, meta descriptions, robots directives, canonicals, structured-data types and H1s. The first run found differences caused by relative URLs. After one fix, there were zero differences across all 217 pages checked.

Claude Code can write and run this comparison quickly. A person should read the results, especially the "no differences" result: confirm the script actually compared what you think it did. Our article on Claude Code for technical SEO covers parity checks and other audit tasks.

Step 6: QA in a real browser

• Check a sample of every page type, not just the homepage. Look at the second and third pages a script produced, not only the first.
• Test every form end to end, including where the submission lands.
• Check menus, accordions, popups and other interactive parts on desktop and mobile.
• Run a broken-link check across the whole site.
• Measure performance on specific pages before and after.

On our site, delaying theme scripts until first interaction took a desktop PageSpeed Insights lab score from 56 to 86 on the pages we tested, and Total Blocking Time from about 1,200 ms to near zero. CSS requests on a typical page fell from 75 to 4. Those are our own lab tests on specific pages, not field data, and your results will depend on your site.

Step 7: launch and monitor

Launch when a person has approved the staging site and the redirect tests pass. Then watch closely. Google says to "expect temporary fluctuation in site ranking during the move," and that for medium-sized sites it "can take a few weeks or more" for the new URLs to replace the old ones in results. Monitor Search Console for crawl errors and 404s, check that analytics and forms still record, and keep the old site's content available until you're confident nothing is missing.

The risks, and the checks that catch them

We cover these and more in common Claude Code mistakes on websites, and the full story is in our eseospace.com rebuild case study.

Who does what

On our rebuild, people decided fidelity over clean code, chose the host, approved every deploy and owned brand facts, prices and claims. Claude Code did the engineering it was asked to do and applied changes at a scale no one would do by hand. After launch, the same setup let us run an accuracy audit that applied more than 4,400 corrections across about 750 pages as scripted edits, each tested on a copy first. That split, people deciding and approving, the agent building and checking, is what made the project manageable.

Conclusion

Claude Code can make a large website rebuild practical for a small team, but the migration basics still decide whether it succeeds: a complete inventory, human decisions on design and URLs, tested redirects, an SEO parity check, real browser QA and close monitoring after launch. If you'd like help, see our Claude Code development service for rebuilds, or our website migration services. More guides are in our Claude Code Guide.

Frequently asked questions