Can Marcus edit an existing site I built elsewhere?

How importing existing HTML works

Marcus lets you paste HTML into a new project as a foundation. The AI reads the structure and content, then uses that as context when you give it instructions. This works reasonably well for simple pages with clean markup—basic landing pages, blog posts, or documentation where the structure is straightforward.

The caveat: Marcus doesn't preserve your exact CSS classes, framework dependencies, or custom JavaScript. It interprets the content and rebuilds the page using its own component system and styling approach. Think of it less like opening a PSD in Photoshop and more like handing a designer a screenshot and asking them to recreate the concept.

Why full migration is tricky

Most real-world sites carry baggage. Webflow exports include hundreds of auto-generated classes. WordPress themes bundle plugins, shortcodes, and PHP templates. Hand-coded sites often have custom build scripts, preprocessors, or framework-specific patterns. Marcus can't run Webpack configs or interpret Liquid templates—it generates static HTML, CSS, and vanilla JavaScript.

If your existing site relies on a CMS, e-commerce backend, or third-party integrations, those won't transfer automatically. Marcus doesn't connect to WordPress databases or Shopify APIs. You'd need to rebuild those connections manually or rethink how your site handles dynamic content.

The practical migration path

Instead of trying to port everything, describe what you want the new site to do. List the pages you need, the key sections on each page, and any specific functionality. Marcus works best when you treat it like a brief rather than a code parser. Say "I need a homepage with a hero section, three service cards, testimonials, and a contact form" instead of pasting 2,000 lines of Webflow export.

For content, you can paste text blocks directly or reference your old site as inspiration. Marcus can match tone and structure without needing to dissect your old markup. If you have images, you'll upload those separately—Marcus doesn't scrape assets from URLs.

What you keep and what you lose

You keep your content, your general layout intentions, and your brand direction. You lose framework-specific code, precise pixel measurements from design tools, and any custom scripts that aren't standard JavaScript. Animations built with GSAP or Framer Motion won't transfer—you'd describe the animation you want and Marcus builds it with CSS or simple JS.

SEO elements like meta tags, alt text, and heading structure carry over if you paste them or specify them in your instructions. Structured data and Open Graph tags work the same way—tell Marcus what you need and it writes the markup. Your old site's analytics snippets or tracking codes can be added manually in the project settings.

When importing makes sense

Importing works well for single-page sites, simple marketing pages, or documentation where the structure is mostly semantic HTML. If your existing site is a clean, static page without heavy framework dependencies, pasting the HTML gives Marcus a decent starting point. From there, you can iterate with natural language edits.

It also makes sense when you want to preserve very specific content formatting—long-form articles with specific heading hierarchies, tables, or ordered lists. Marcus respects semantic HTML structure, so a well-marked-up article will translate more reliably than a page built entirely with divs and utility classes.

Recommended approach for most migrations

Start fresh. Use your old site as a reference, not a direct input. Take screenshots of the layouts you like, list the features you need, and describe the user journey you want. Marcus builds faster and cleaner when it's not trying to reverse-engineer someone else's code decisions.

If you're on a Webflow annual plan or a WordPress site with years of content, consider running both in parallel during the transition. Build the new version in Marcus, test it thoroughly, then switch DNS when you're confident. You're not locked into Marcus—every project exports as a ZIP of standard HTML, CSS, and JavaScript files, so you can host it anywhere or hand it off to a developer if needed.