Foreword
Merging two websites is more than a technical project, it's an opportunity to build something better than either site was on its own. Done well, it results in a cleaner design, a more maintainable codebase, and a stronger presence in search. Done poorly, it creates visual inconsistency, content chaos, and an organic traffic drop that takes months to recover from. This guide covers the three areas that matter most: design, development in Webflow, and SEO, so you can approach your migration with a clear plan rather than a cleanup job waiting to happen.
A site migration is one of those rare moments where you have genuine permission to stop and question everything. The temptation is to treat it as a technical exercise, get the content moved, keep things looking roughly the same, and ship it. But if you're merging two sites, you have something more valuable on your hands: a forcing function to consolidate two design languages into something more coherent, more intentional, and easier to maintain long-term.
Before any design work begins, do a component inventory of both sites. Go through every page, every section, every UI pattern, and list what exists. You'll almost certainly find that both sites have their own version of a card, their own approach to navigation, their own button styles. The goal isn't to pick a winner, it's to understand what you actually need, and design one version that does the job properly.
If you have a design system, this is the moment to make it non-negotiable. Every component on the merged site should come from the system, and anything that doesn't exist in the system should be added to it before it goes anywhere near a page. This discipline pays dividends immediately: you end up with a site that's visually consistent, faster to build, and genuinely easier for whoever maintains it.
The other thing worth doing at this stage is mapping the user journeys that cross both sites. If customers have historically moved between the two, different areas, different service lines, different audiences, think carefully about how the merged information architecture serves them. Navigation, page hierarchy, and the way you name things all need to reflect the new unified reality, not the legacy structure of two separate businesses or teams.
One practical note: make these decisions explicitly and document them. Write down why you chose one design direction over another, which components were retired, and what the merged IA looks like. It sounds obvious, but without that record, you'll be relitigating the same decisions six months later.
Webflow is an excellent platform for this kind of project, largely because it lets you build in parallel. You can construct the entire merged site in a staging environment and switch over when you're ready, without touching the live sites until go-live day. That's a significant operational advantage, and it's worth building your project timeline around it.
That said, there are a few areas where Webflow requires upfront thinking that can't easily be undone later.
Start with your CMS structure. Webflow's CMS collections have field limits, and the structure you set up is difficult to change once live content is inside it. Before you start building, map out every content type across both sites, blog posts, products, team members, case studies, whatever you have, and design your collection architecture for the merged site from scratch. Don't import one site's structure and bolt the other onto it. This is also a good moment to audit your content itself: what's being merged, what's being retired, and what needs to be rewritten for the new site.
Sort out your class naming before you build. If both existing sites were built in Webflow, they've almost certainly developed their own class conventions. Merging two class structures into one project is messy, and inconsistent naming is one of the main reasons Webflow sites become hard to maintain. Agree on a naming convention before anyone writes a single class name in the new project, and stick to it across the team.
Be deliberate about your symbols and global styles. Webflow's global colour swatches, text styles, and components are where your design system lives at a code level. Set these up to match your design tokens before you start building components. It means any future updates cascade correctly rather than requiring manual fixes across hundreds of elements.
Plan your content migration as a project in itself. Webflow doesn't have a native site-merge tool, so moving CMS content from two sites into one means exports, reformatting, and careful imports. For larger content sets, tools like a simple CSV workflow can help, but either way it needs time, a clear owner, and a QA process. Don't leave content migration to the week before launch.
Site migrations are where SEO gains get lost. It happens quietly, a redirect that was missed, a canonical tag that points somewhere wrong, a page that was indexable on the old site and blocked on the new one. The organic traffic drop shows up weeks later in Search Console, by which point untangling the cause is painful. The good news is that with the right preparation, most of this is entirely preventable.
Redirect mapping is the most important thing you will do. Every URL on both existing sites needs a 301 redirect to its equivalent on the new site. Not just the homepage. Not just the top-level pages. Every blog post, every product page, every team bio. Build a spreadsheet with old URL in one column and new URL in the other, and get it signed off before go-live. The redirect mapping process will also surface content decisions you haven't made yet, what happens to pages that don't have a clear equivalent on the merged site? Decide early, and map those to the most relevant page rather than sending them to the homepage.
Audit for duplicate content before you merge. If both sites covered similar topics, which is common when two brands or product areas are coming together, you likely have overlapping content. Merging it without consolidating creates pages competing against each other in search. Pick the strongest version of each piece, update it, and use 301s to fold the weaker versions in. If both versions have meaningful traffic and links, consider combining them into a single, more comprehensive page.
Carry over your metadata carefully. Title tags and meta descriptions from your best-performing pages shouldn't be rewritten unless they genuinely need improving. During a migration it's easy to let these get overwritten by CMS defaults or template placeholder text, build a QA step that checks metadata on all key pages before and after go-live.
Set up Google Search Console for the new site before you launch. Verify ownership, submit your sitemap, and make sure you have a baseline picture of crawl coverage and index status from day one. If there are issues post-migration, crawl errors, pages dropping out of the index, traffic falling on specific sections, you want to catch them immediately, not when someone notices the numbers are down in a monthly report.
If you're consolidating two domains, be clear about which one you're keeping and why. The domain with stronger authority, more inbound links, and more established search presence is usually the one to keep. If you're moving to a new domain entirely, the redirect mapping becomes even more critical, and you should expect a period of ranking fluctuation regardless of how well the migration is executed. That's normal, communicate it to stakeholders in advance so it doesn't become a crisis.
A well-executed site migration doesn't just maintain what you had, it moves you forward. Cleaner design, a more manageable codebase, and search visibility that holds (or improves) are all achievable outcomes when the groundwork is done properly.
We recently put all of this into practice with UKFT, merging two separate sites into one cohesive destination and moving the whole thing from WordPress to Webflow in the process. If you want to see what the approach looks like in the real world, the decisions, the build, and the results, take a look at the case study.
