So, your site just relaunched. The new design? Slick. The content? Polished. Everyone on your team is breathing a collective sigh of relief. But then the traffic tanks. Rankings go haywire. Leads dry up. What gives? This is the part of a site migration that rarely gets the spotlight: the post-migration SEO audit. It’s not just a checkbox. It’s the difference between growth and a digital nosedive. Most teams think they’ve done their part with redirects and an updated sitemap—but those are just the basics. The real issues show up after the launch.
Let’s talk about what you probably missed—and why it matters more than you think.
Why Post-Migration SEO Is So Often Botched
Here’s the hard truth: migrating a website is not a one-day job. The moment you push the new site live, you’re entering Google’s waiting room. And Google? It doesn’t hand out rankings for free. Every decision—from how your redirects are structured to how your JavaScript loads—affects how the new site is perceived and indexed.
In many cases, what tanks your SEO isn’t some massive technical flaw. It’s the sum of small oversights—links that break, pages that disappear, settings that were perfect in staging but catastrophic in production. And once those cracks start forming, they quickly turn into full-blown search engine sinkholes.
Redirects Are Not a “Set It and Forget It” Task
The number one post-migration mistake? Assuming redirects are good just because they exist. The problem isn’t just missing redirects—it’s the wrong kind of redirects, or messy redirect chains that confuse both users and crawlers.
If old URLs aren’t properly redirected to relevant, high-authority new pages, all that SEO equity built over time just vanishes. Worse, if your team used temporary 302 redirects instead of permanent 301s, Google may not transfer the ranking signals at all.
Redirects should always be double-checked after launch, using crawl tools and server log analysis. If they’re misfiring, you won’t just lose rankings—you’ll lose user trust too.
Crawl Errors Are the Silent Killers
Post-launch, your site is like a freshly installed software system. Bugs are inevitable. Googlebot starts crawling the new structure almost immediately, and any crawl error it encounters is like a red flag.
Missing pages (404s), broken internal links, and incorrect DNS settings can prevent important parts of your site from being indexed. You might think a few errors are no big deal—but Googlebot sees them as instability, and that can lead to slower crawling and delayed indexation.
Monitoring crawl stats in Google Search Console in the first few weeks is critical. This is not something you can revisit in a month. The damage from neglected crawl errors begins immediately after the switch.
The Analytics Blindspot That Can Cost You Months of Data
This one stings. Your team spent months preparing for the relaunch, but the first week post-launch shows a sudden drop in conversions. Or does it?
What many teams fail to realize is that migrating a website often disrupts tracking. GA4 configurations might not carry over. Google Tag Manager triggers might stop firing. Event tracking might go dark.
If you’re seeing suspiciously low numbers after migration, don’t assume your traffic dropped. Check if your analytics broke. Make sure your ecommerce tracking, goals, and user behavior metrics are all still capturing the right data.
When analytics go blind, so do your decisions. And fixing it a month later means losing a month’s worth of insights.
JavaScript and Rendering: The Invisible Barrier
Modern websites rely on JavaScript like never before. But Googlebot doesn’t always execute JS the same way a human browser does.
That cool new feature your devs built? It may not be visible to Google at all.
This is especially problematic when important content—like product descriptions or service details—is only visible after JavaScript runs. If Googlebot doesn’t render the content, it doesn’t exist in the index. That’s a serious problem.
You should inspect your pages using Google Search Console’s URL Inspection Tool. Compare what you see vs. what the bot sees. If key elements are missing, it’s time to revisit your rendering strategy.
Internal Linking: The Web of Authority That Often Breaks
Internal links are the veins of your SEO body. When you migrate a site, chances are your structure changes—and so do your links. The problem? Many links point to URLs that no longer exist or weren’t redirected properly.
This breaks the authority flow. It prevents crawlers from reaching important content. And it messes with your user journey.
After migration, your first internal crawl should be ruthless. Identify every broken internal link. Map out key pages and ensure they have multiple internal pathways pointing to them.
If you had a pillar-cluster strategy pre-migration, make sure that structure survives the move.
Here’s one of the only lists we’ll include:
Top internal link mistakes post-migration:
- Links pointing to staging or dev environments
- Leftover anchor text pointing to deleted blog posts
- Footer/nav links using outdated URLs
- Tag or category pages that no longer exist
Fix these fast. Your rankings will thank you.
Mobile-First Indexing Isn’t Optional—It’s the Rule
Google now evaluates your website based primarily on its mobile version. And yet, many businesses still focus on desktop performance during a relaunch.
This is a dangerous oversight.
A site that’s “responsive” isn’t automatically mobile-optimized. If your mobile experience hides content, relies on hover states, or delivers slow load times, you’re likely losing visibility.
Use mobile rendering tools. Don’t just resize your browser and call it a day. Emulate devices. Review layouts. And above all, check that your key content is accessible and readable on every screen size.
Lost Backlink Equity: The Hidden Cost of Poor Redirects
Imagine earning hundreds of backlinks over years—media mentions, guest posts, resource pages. Now imagine those links pointing to 404 pages because the URLs changed and the redirects weren’t set.
Welcome to one of the most painful post-migration SEO problems: link equity loss.
When those valuable external links hit dead ends, they no longer boost your authority. In fact, they may work against you.
Here’s your second and final list:
Steps to reclaim lost backlink authority:
- Run a backlink report using tools like Ahrefs or Semrush
- Identify top-linked pages from the old domain or structure
- Check if those URLs still resolve or redirect properly
- Set up 301s for anything that’s currently broken or pointing wrong
A single broken backlink from a high-authority domain can have a real impact. Reclaiming that equity isn’t optional—it’s essential.
Don’t Let Technical Debt Destroy Organic Growth
Your website is alive. It breathes. It evolves. And after a migration, it’s at its most vulnerable.
You can’t afford to assume everything’s working just because the homepage loads.
You need to crawl. Monitor. Test. Re-crawl. Fix. And repeat. Your post-migration SEO audit should be obsessive. Because Google is watching, and it doesn’t hand out second chances easily.
If you’ve just launched or are about to relaunch your site, don’t wait for rankings to fall before you take this seriously. A post-migration SEO audit is your insurance policy against invisible chaos.
Need a team to make sure you don’t miss a beat? Get an expert audit with SEO Sets and make your relaunch a true success—not just a redesign.
FAQs
1. How soon should I audit SEO after a site migration?
Immediately. The first 72 hours post-launch are critical for spotting crawl errors, redirect failures, and analytics issues.
2. Will my rankings always drop after a relaunch?
Not necessarily. A well-executed migration with proper SEO auditing can maintain or even improve rankings. Drops usually signal missed technical steps.
3. How long does it take Google to reindex a migrated site?
It depends on your crawl budget and internal linking structure. Most well-optimized sites get reindexed within a few days to a few weeks.
4. What tools are best for post-migration SEO audits?
Screaming Frog, Google Search Console, GA4, Ahrefs, Sitebulb, and log analyzers are essential for spotting issues.
5. Can poor JavaScript rendering really affect SEO?
Absolutely. If Googlebot can’t see or execute your content, it doesn’t exist in the index. JavaScript-heavy sites need careful audit attention.
