Change Your Website Without Losing Your SEO – Site Migration with Topdog

Changing CMS, moving to a new domain, or redesigning your site? These are exactly the moments when companies lose their Google rankings and their traffic, often without understanding why until it’s too late. Topdog has a proven process for migrating websites while keeping your SEO intact. Done right, traffic can even increase.

A site migration covers any major technical change to a website: a change of domain, a change of CMS or platform, a redesign, or a new URL structure. What they all have in common is this: Google has to understand what happened, or your new site gets treated as a completely new, unproven website.

Who needs to think about SEO when migrating a website?

If you’re migrating your website, you should keep search engine optimization in mind if you:

• Are a CTO or technical lead tasked with making sure the new website performs better from an SEO perspective.
• Are a marketing manager responsible for leads and traffic to your website.
• Are a CEO concerned about traffic and revenue when your company gets a new website.
• Run a digital agency and find that SEO and Google can feel difficult and risky, and want to make sure that building a new website for your client delivers benefits rather than drawbacks.

What happens if you change your website without an SEO plan?

Every page on your website has its own URL that Google has indexed and ranked. When those URLs change and nobody tells Google where the content went, three things happen: visitors hit 404 pages, rankings fall, and traffic disappears, sometimes more than 90% of your Google traffic. You can repair the damage afterwards, but it takes months and costs you visitors and revenue the whole time.

That’s why SEO needs to be part of the migration project before the new site is built, not after launch.

Topdog’s method: automated redirect handling

Most migrations are handled with a manual redirect list: a spreadsheet mapping old URLs to new ones, row by row. That works for 50 pages. It falls apart at 5,000.

Topdog maps old URLs to new ones automatically instead, using rule-based matching on page slugs. As long as a page, product or category keeps the same slug, or the slug changes according to one consistent pattern, our redirect rules catch it automatically, wherever the page ends up in the new structure.

That’s what makes the migration scalable: the method works the same way for 50 URLs as for 50,000, and across any number of language markets, without the manual workload growing.

A pattern-based exception is allowed: if every product slug picks up a platform-generated ID in the same position, for example (old-slug → old-slug-4821), we can build a rule for that too. What doesn’t work is arbitrary renaming page by page: that forces you back to the manual spreadsheet, with all its potential for error.

Changing CMS? Different platforms, different pitfalls

Every platform change comes with its own SEO risks. Some examples from projects we’ve delivered:

•       WordPress: permalink structures and plugin-generated URLs that change during a move.
•       WooCommerce: product variants and filters can generate thousands of URLs that the redirect rules need to catch.
•       Shopify: a fixed URL structure (/products/, /collections/), which makes slugs decisive since you can’t control the folder structure.
•       Magento: complex category structures and stock-driven URLs that require pattern-based rules.
•       Optimizely/Episerver: enterprise environments where several markets and languages need migrating at once.
•       PrestaShop: ID-based URLs that often get regenerated during a move.

Whatever the platform, the same principle applies: if the slugs are preserved, or changed following a documented pattern, the migration can be automated.

Topdog’s process for migrating your site

When migrating sites, we at Topdog follow a four-step process:

1. Analysis and requirements: reviewing the plan for gaps

There’s often already a plan in place for what the new site will look like. Based on that plan, we assess it and give you feedback on what’s missing or needs improving. The factors we consider are technology, content and user experience.

If one or more of these factors falls short, you’re almost certain to see a drop in traffic. That’s why it’s important to bring the SEO agency into the project as early as possible.

This step results in a detailed set of requirements that’s used throughout the project.

We think it through before we start: we build the project around where you are today and the problems that actually need solving, with one accountable expert and measurable goals. At Topdog, you work directly with the expert doing the analysis: no project managers or middlemen.

2. Pre-launch

By this stage, the site is far enough along for us to review it in the development environment. Working from the list of requirements, we go through the site and give you feedback on what does and doesn’t work from Google’s perspective. At this point, we can also start putting together forecasts for how your new website will perform in Google.

3. Launch analysis

Around the time of launch, we evaluate the site against the requirements again. You then get our feedback along with an action plan.

4. Post-migration analysis

After around a month, there’s enough data for us to work with you to map out what’s happened and draw conclusions. From there, we put together a list of activities for you to take forward.

Only once the site has stabilised, normally 2–3 months after launch, do we recommend resuming any planned content work. That way, you can keep the impact of the migration separate from the impact of any content changes.

How to prepare: three rules for a successful migration

This is what we ask of you as a client, and it also happens to be the best advice for anyone about to change their website:

1.     Don’t touch the slugs. Keep the slug for every page, product and category that’s carrying over, or change them following one single, documented pattern. The structure around them can change freely.
2. Freeze the content during the migration window. No changes to titles, meta descriptions or copy while the move is underway. The migration needs to be the only variable, or there’s no way to tell whether a change in traffic comes from the move or from the content.
3. Changing the design? Keep the content blocks. Every section on the old page needs an equivalent on the new one. Adding a block is fine; removing or merging blocks in the middle of a migration makes it impossible to diagnose any change in traffic.

Why hire Topdog for your site migration?

The biggest obstacle to a successful migration is rarely knowledge: it’s execution. Topdog’s strength is turning a plan into reality alongside your technical team, through structure, prioritisation and a shared process.

•       You work directly with the expert. The same person analyses, plans and drives the work: short decision paths and a fast pace, even when it’s almost Christmas Eve (just ask Gilion).
•       An automated method. We use rule-based redirects instead of error-prone spreadsheets, so the method scales across any site size and any number of language markets.
•       Proven in complex environments. Fass (highly regulated, “carried out without a single error”), Gilion (a domain change plus a rebrand for the US market), and an e-commerce migration that split one site into two following a company sale.
•       Projects with clear goals: a requirements spec, measurement and accountability for results, not billed hours.