A migration is any change that alters how search engines see your site: a redesign, a new platform, a domain change, a switch to HTTPS, a restructure of URLs, or a merge of two sites. It is one of the riskiest moments for organic visibility, because mistakes can remove pages from search or sever the signals that earned their position. No agency can remove that risk, but good process reduces it.
This checklist is for the buyer: what to ask for and verify, not how to execute each technical step.
Before you hire for a migration
- Involve SEO at the start. Changes decided in design and development without SEO input are expensive to reverse.
- Define the type of migration. Different changes carry different risks: domain change, URL change, platform change, content consolidation, design only.
- Ask for migration-specific experience. Request case studies that describe the process and issues, not just the result. See Evaluating an SEO Case Study.
- Find platform experience where relevant, e.g. Shopify work.
- Clarify who does what. The agency, your developers and a design vendor each need written responsibilities.
Phase 1: Planning and baseline
Require:
- A full inventory of existing URLs, from crawls, analytics, search console data and sitemaps, including pages with backlinks or conversions.
- A baseline of performance: visibility, traffic by section, indexed pages, conversions, and technical measurements, so you can compare afterward.
- A list of pages and content that matter most, agreed with the business.
- A decision on what changes and what stays: URLs, titles, copy, templates, internal links, structured data.
- A timeline avoiding critical business periods where possible.
- A risk register naming what could go wrong and who is responsible for each item.
Phase 2: Redirect and structure mapping
Require:
- A page-to-page redirect map from old to new URLs, prioritizing relevance. Mass redirection of everything to the homepage is a red flag.
- Handling of parameters, tags, pagination and legacy URLs.
- Preservation of valuable content or an explicit reason for removing it.
- Internal linking plan in the new structure.
- Plan for canonical tags, hreflang and structured data if applicable.
Phase 3: Staging review
Before launch, ask the agency to test the staging environment:
- Crawl the staging site and compare it with the live one.
- Check that staging is blocked from indexing, and that blocking is removed at launch. Forgotten blocks are a classic failure.
- Verify redirects, status codes, canonical tags, titles, headings and internal links.
- Test rendering and performance on key templates.
- Confirm analytics and conversion tracking function.
- Obtain a written sign-off checklist with owners.
Phase 4: Launch
- Agree a launch window with agency and developers available.
- Have a rollback plan and criteria for using it.
- Submit updated sitemaps and, for domain changes, use the relevant search engine tools.
- Immediately re-crawl and verify redirects, indexing directives and robots rules.
- Check that tracking and forms work.
Phase 5: Post-launch monitoring
Require a defined monitoring period with named responsibilities:
- Daily or frequent checks at first for errors, indexing and crawl behavior.
- Comparison against the baseline by section.
- A list of issues found and their fix status.
- Updating of internal links and external references you control.
- A review meeting after the agreed period, with findings documented.
Some fluctuation is normal while search engines process changes. Do not accept "it is normal" as a substitute for diagnosis; ask what specifically is being observed and what would indicate a problem.
Contract points specific to migrations
- Scope that names the migration deliverables above.
- Defined acceptance criteria.
- Who pays for fixes that arise from the agency's oversight versus developer errors.
- Access to staging and documentation.
- Post-launch support terms. See Monthly Retainer vs Project Pricing.
Red flags
- No baseline captured.
- No redirect map, or a map created after launch.
- Promises that rankings will not change.
- SEO excluded from design and development meetings.
- Launch on a date driven only by marketing, with testing compressed.
- No monitoring plan.
Verification and next steps
Ask each candidate to describe a past migration, including problems. Check how the claims are sourced: listings on this site mark whether each comes from the agency's own site, a published case study or independent corroboration, and sponsorship never buys verification. Use the technical SEO directory to find agencies offering migration support, and see Questions to Ask Before Signing for contract points.