Website migrations can be high-stakes projects. Whether you are moving to a new CMS, rebranding, or restructuring your site, the primary goal is to improve your digital presence without sacrificing the organic traffic you’ve worked years to build.
At Atkinson Smith Digital, we’ve led enterprise-level migrations for brands like Hitachi and NerdWallet, as well as for local and national sites. Read on to discover our proven process for ensuring your migration is a success rather than a cautionary tale. This guide is primarily geared around migrating to a new CMS platform or changing the site’s design, but can also apply to changing your domain name.
1. Planning: The Foundation of Success
The most critical mistake is treating SEO as an afterthought. To avoid cost overruns and massive traffic loss, SEO must be factored into the project scope from day one.
Your new site must prioritise SEO fundamentals:
- Crawlability: Can search engines find all your pages?
- Site Architecture: Is the internal linking logical and supportive of high-value pages?
- Rendering: Ensure content can be crawled and rendered without relying on JavaScript, which is important for Google, but critical for LLMs bots like ChatGPT, which cannot render JavaScript content.
The Golden Rule of Migrations: The most successful migrations—those that maintain 100% of their traffic—tend to be those that make the fewest changes. Whenever possible, keep your URLs, content, and metadata exactly the same. This is often achievable where migrations are aimed at improving look and feel, but less so when migrating from a legacy CMS or changing domains.
For more involved migrations such as these, a traffic benchmark process can be helpful, which we explore below.
2. Traffic Benchmarking & Forecasting
Before making any changes, you must understand the potential impact. Benchmarking identifies traffic risks and helps stakeholders understand the “risk vs. reward” of the project.
Our typical analysis process includes:
- Data Collection: Pull 12 months of Search Console data by URL and folder
- The “Counter-Narrative”: Forecast what would happen if you did not migrate
- The Migration Forecast: Estimate traffic changes based on proposed updates
Pro Tip: For affected URLs, we often model a 30% temporary drop immediately after migration that recovers over three months. Meanwhile, URLs that receive no content changes may initially see a 10% drop that recovers after a month.
While not an exact science, these estimates help to capture a range of outcomes that your business can plan for, for example temporarily boosting PPC spend to plug any estimated gaps in organic leads or revenue.
3. Creating a Migration Checklist
A successful migration is a game of details. You need a comprehensive checklist that covers every stage of the process, when they will be completed and who by.
To get started, you can use our Example Site Migration Checklist by Atkinson Smith Digital, and customise this to your specific needs.
4. Auditing: Live vs. Development
You cannot fix what you haven’t measured. This stage requires two distinct audits:
- Live Site Audit: Identify existing issues on your current site so you don’t carry them over to the new one.
- Pre-Launch Development Audit: Audit the new site in a staging environment.
- Comparison Tip: Use Screaming Frog’s “Compare Mode” to identify discrepancies in metadata or internal linking between the old and new sites. Make sure to save a copy of your full crawl of the old site in case you need to retrieve it in future after the migration.
- Crucial Safety Step: Ensure your development site is set to “noindex” so Google doesn’t accidentally index it before launch.
5. The Art of 301 Redirect Mapping
Beginners often make the mistake of redirecting all old URLs to the new homepage. This can be a disaster for SEO.
Every single URL must be mapped like-for-like to the exact page that replaces it using a 301 (permanent) redirect status code. Do not use a 302 status code, which refers to a temporary redirect”, and does not accurately tell search engines how to treat the new URLs.
- Trailing Slashes: Remember that adding or removing a trailing slash counts as a new URL and requires a redirect.
- Legacy Redirects: Check redirects that have existed for under 12 months; these should be remapped to the new destination to maintain link equity. Updating legacy redirects that have existed for longer than a year is fine, but not strictly necessary.
6. Launch & Post-Migration Monitoring
Once the site is live, the work isn’t over.
Immediately check that the site is not accidentally blocked via robots.txt and verify that your redirects are functioning correctly. You can replicate your audit from step 4 between your pre-migration crawl export and your new live site to ensure everything has migrated as expected.
Over the following weeks, monitor performance closely and compare it against your initial forecast to keep stakeholders informed.
Let Us Manage the Risk for You
Website migrations are complex, but they don’t have to be a source of business anxiety. By following a structured process, from rigorous pre-migration analysis to detailed redirect mapping, you can protect your search visibility and build a foundation for future growth.
At Atkinson Smith Digital, we specialise in providing “traffic light” graded recommendations and data-driven modeling to give you and your stakeholders peace of mind throughout the transition. Our expert support ensures that technical standards are met and that your organic traffic remains a long-term asset rather than a short-term risk.
If you are planning a migration and want to ensure your rankings are protected, we would love to help. Our migration support projects typically range from £2,000 to £5,000, depending on the complexity and scope of the site. For a no obligation discussion about your project, why not get in touch?