Website Migration SEO Guide

Website migration—whether changing domains, upgrading platforms (like moving from WordPress to another CMS), or overhauling server architecture—is a major undertaking. Anyone who's been through it knows that one small misstep can cause traffic and rankings to plummet overnight.

Typically, the focus is on migrating HTML page content, setting up URL redirects, and handling technical configurations. While this is crucial, it often overlooks a critical point: search engines index and rank more than just HTML pages! Your site likely has a wealth of PDF documents, images, and even videos that contribute to your traffic or hold valuable backlinks.

If these non-HTML assets are neglected during a migration, you risk significant traffic loss and diminished SEO performance.

This article explores how to think beyond HTML pages when creating a migration strategy. We'll cover how to incorporate often-ignored assets like PDFs, images, and videos, seize optimization opportunities, and ensure a smooth transition—or even use the migration to boost your SEO. This is especially vital for enterprise websites with custom CMSs or complex tech stacks.

1. PDF Documents: The Forgotten Source of Traffic and Optimization

Many websites, particularly in the B2B, education, government, and finance sectors, host numerous PDF documents (e.g., white papers, reports, product manuals). Don't underestimate them; they can sometimes drive substantial organic traffic and accumulate valuable backlinks.

Before Migrating, Take Inventory:

1. Audit Your PDF Assets: How many PDFs are on your site? Where are they located?
2. Evaluate Their Value:
   • Traffic Contribution: Use Google Analytics (GA4) to check PDF views and sources. Are they bringing in organic search traffic?
   • Backlink Value: Use tools like Ahrefs or SEMrush to see if external sites are linking to your PDFs. What is the quality of these links?
   • Internal Links: How are the PDFs linked within your site?

How to Conduct the Audit:

• SEO Crawlers: Use tools like SeoSpeedup's Site Crawler, Screaming Frog, or Sitebulb to crawl your site and filter for URLs ending in .pdf.
• Search Console: Google Search Console can provide data on indexing status and traffic.
• site: Operator: Use site:yourdomain.com filetype:pdf in Google search for a rough estimate of indexed PDFs.

Migration Strategy and Optimization Opportunities:

a. Convert PDFs to HTML: Is It Feasible?

Before migrating, seriously consider: Can this PDF content be converted into an HTML page?

While PDFs have advantages for print-ready formatting, converting them to HTML is generally better for SEO:

• Crawling & Indexing: HTML is easier for search engines to crawl and understand.
• Accessibility: It's more friendly to screen readers and users with disabilities.
• Mobile-Friendliness: HTML allows for responsive design, improving the mobile experience.
• Load Speed: HTML pages typically load faster than equivalent PDFs.
• Link Equity: HTML pages more effectively acquire and pass PageRank.
• Content Updates: Maintaining and updating HTML is much simpler.
• Structured Data: You can add Schema.org markup to HTML for rich snippets.

If a PDF's content is valuable and suitable for a web page, converting it during migration can yield long-term SEO benefits.

b. PDF Hosting Strategy: Where to Keep Them?

If you decide to keep the PDF format, you need a solid hosting plan.

• Hosting Location: Will you keep PDFs on your main web server or use object storage (like AWS S3, Azure Blob Storage, or Google Cloud Storage)? Object storage often offers better cost, scalability, and CDN integration.
• URL Structure: Will the PDF URLs change post-migration? If using object storage or a CDN, will they still be accessible via your primary domain (or a subdomain like files.yourdomain.com)? URL changes directly impact internal and external links.

Clarify the hosting plan and URL conventions with your development team.

c. Redirects! Redirects! Redirects!

For any PDFs that drive traffic, have valuable backlinks, or are converted to HTML pages, you must set up 301 redirects between the old and new URLs. This is a critical step to ensure link equity is passed and users aren't met with dead ends.

Add all necessary PDF redirects to your redirection map.

d. Cleanup and Indexing Control

A migration is the perfect time to clean up redundant files and fix improper indexing.

• Remove Unnecessary PDFs: Are there outdated, low-value PDFs that can be deleted?
• Block Unwanted PDFs: Some PDFs (internal docs, old policy versions) shouldn't be in search results. You can manage this via:
  • robots.txt Disallow: Prevents crawling.
  • X-Robots-Tag: noindex HTTP Header: Allows crawling but prevents indexing (recommended over robots.txt as it can still pass some link signals).
  • Access Control: For sensitive files, restrict access at the server level.

For example, I once had an insurance client whose contract details were being indexed. During their migration, we used the X-Robots-Tag to de-index them successfully.

Risk Alert:

• Ignoring redirects is a disaster. Failing to redirect valuable PDFs will result in lost traffic and link equity.
• Benchmark your data. Before migrating, record the URLs, traffic, and backlinks for your key PDFs to compare and troubleshoot post-migration.

2. Images: Visuals are Traffic Gateways Too

Images are vital for e-commerce, travel, design, and recipe sites, and they can drive significant traffic through image search. An image migration strategy is non-negotiable.

Migration Strategy and Optimization Opportunities:

a. XML Image Sitemaps: Accelerate Indexing

It can take time for search engines to discover and index images on a new site. To speed this up, it's highly recommended to:

• Create a dedicated Image Sitemap: Include all important image URLs in an image-sitemap.xml file.
• Or, embed image info in your standard XML sitemap: Use the <image:image> tag within a page's URL entry.

This helps search engines discover images faster and associate them with relevant page content, boosting their visibility in image search.

b. Alt Text: A Priority Before and After

Alt text is fundamental to image SEO and accessibility.

• Pre-Migration Audit: Check if your current site is missing alt text. Is it too generic? Can it be optimized with relevant keywords?
• Implementation During Migration: Ensure all meaningful images on the new site have descriptive alt text.

c. Page Speed & Image Optimization: The Perfect Time to Act

Images are often the biggest culprits for slow page loads. A site migration is the perfect opportunity for a full-scale image performance overhaul. SeoSpeedup's Site Audit can pinpoint exactly which images need attention. Discuss these common optimizations with your dev team:

• Resizing and Compression: Properly size images before uploading and use tools like TinyPNG or Squoosh for compression.
• Responsive Images (<img srcset>): Serve different image sizes based on the user's device.
• Lazy Loading: Use the HTML loading="lazy" attribute for off-screen images.
• Modern Formats: Prioritize WebP or AVIF over JPEG/PNG for better compression and quality.
• Image CDN: Use a CDN like Cloudflare or AWS CloudFront to serve images from edge locations closer to the user.
• Priority Hints: Use fetchpriority="high" for your LCP (Largest Contentful Paint) image to tell the browser to load it first.

d. Avoid Text in Images

Search engines can't read text embedded in images. If key information (headings, CTAs, contact info) is part of an image, it's invisible to them.

During migration, extract this text and present it as standard HTML text. I've seen rankings for service pages improve dramatically after this simple change.

e. Image Structured Data (Schema.org)

Use Schema.org to add rich context to your images.

• ImageObject: Mark up details like author, copyright, and description.
• primaryImageOfPage: Specify the main representative image for a page.

While this may be a lower priority for some migrations, it's worth implementing if image SEO is critical to your business.

Risk Alert:

• Monitor image traffic. If you get significant traffic from image search, monitor it closely in Google Search Console (Performance report > Search type: Image) post-migration.
• Verify your CDN domain. If using a CDN with a custom subdomain (e.g., img.yourdomain.com), verify it as a separate property in GSC to monitor its indexing and performance.

3. Videos: Content Can't Be Redirected, Embedding is Key

Unlike web pages or PDFs, video files themselves generally cannot be 301 redirected.

The core principle for video migration is: ensure that if a video was embedded on a page on the old site, the same video is embedded on the corresponding page on the new site.

Migration Strategy and Optimization Opportunities:

a. Video Sitemaps: Tell Search Engines Where to Look

Like with images, a dedicated Video Sitemap or embedding video information (<video:video> tag) in your standard XML sitemap helps search engines discover and index your videos much faster.

b. Video Hosting and CDNs

A migration is a great time to review your video hosting strategy.

• Self-hosting + CDN: Store files on your own server or object storage and use a CDN. Offers full control but requires managing encoding and players yourself.
• Video Cloud Services: Use platforms like AWS Media Services or Google Cloud Transcoder. They provide end-to-end solutions for transcoding, storage, and delivery.
• Third-Party Platforms: Host on YouTube or Vimeo and embed on your site.
  • Pros: Leverages platform traffic, saves on hosting costs.
  • Cons: Sends users off-site, limited SEO value for your domain, less brand control.

For keeping traffic on your site, the first two options are preferable.

c. Video Structured Data (Schema.org)

Structured data is crucial for video SEO.

• VideoObject: Mark up the title, description, thumbnail URL, upload date, and duration.
• Clip: Mark up key moments with timestamps and labels. This can help you earn "Key Moments" rich snippets in Google Search.
• InteractionCounter: Mark up view counts.

Properly implemented video schema can significantly boost your visibility in search results.

Risk Alert:

• Ensure videos are present on new pages. The most critical task is to audit all pages with video embeds and ensure they are replicated on the new site.
• Benchmark your data. Before migrating, record video indexing data (from GSC's "Video pages" report), analytics, and traffic to pages with videos. Compare this data after the migration to spot issues.

Conclusion: Plan Thoroughly, Leave No Stone Unturned

Website migration is complex. While HTML pages are the priority, you cannot afford to ignore non-HTML assets like PDFs, images, and videos. They are integral to your site's traffic, user experience, and overall search performance.

In your migration planning phase, be sure to:

1. Conduct a Full Audit: Catalog all non-HTML assets. SeoSpeedup can automate this discovery process.
2. Evaluate Value: Analyze their current traffic and SEO contribution.
3. Define a Strategy: Decide whether to convert, keep, redirect, optimize, or clean up each asset type.
4. Benchmark Data: Record pre-migration metrics for post-migration analysis.
5. Collaborate: Communicate clearly with your development, content, and design teams.
6. Monitor Post-Migration: Track all key metrics to identify and fix issues quickly.

Investing time in a comprehensive non-HTML asset migration plan will not only prevent potential disasters but also unlock new opportunities to improve your SEO. Don't let these "supporting characters" undermine your successful migration.