Redirect Mapping

Redirect mapping is the process of pairing each old URL with the most relevant new or live URL, then implementing redirects (usually 301s) between them. It is a core task in site migrations, URL restructures, content pruning and 404 clean-ups. Good mapping preserves user journeys, link equity and search visibility; poor mapping, such as sending everything to the homepage, loses them.

How it works

• Collect the old URLs: crawl the old site, and add URLs from analytics, Search Console, backlink tools and server logs so that pages with traffic or links are not missed.
• Collect the destination URLs: the new site’s crawl or sitemap.
• Match them: by hand for small sites; with rules for predictable patterns; or with fuzzy matching on cleaned URL slugs, titles or H1s for large sets. Semantic matching with embeddings helps when wording changed.
• Review: accept high-scoring matches, check medium ones by hand, and decide what to do with pages that have no good match (a parent category, or a 410 if the content is gone for good).
• Implement and test: deploy the redirects, avoid chains and loops, and crawl the old list to confirm each returns a single 301 to a 200 page.

How it’s used in SEO and marketing

• Site migrations and domain moves.
• Fixing 404s that still receive links or traffic.
• Content consolidation, where several thin posts merge into one stronger page.
• Platform or CMS changes that alter URL patterns.

Example

In MLforSEO’s 404 and redirect mapping tutorial, broken URLs and live URLs are compared in Google Colab with several Python libraries, such as FuzzyWuzzy, RapidFuzz and PolyFuzz. Each broken URL gets its closest live match and a similarity score. An old URL like /blog/2019/seo-tips-for-beginners matches /blog/beginner-seo-tips with a high score, so it goes straight into the redirect list; low-scoring pairs are reviewed by hand.

Limitations and things to watch

• String matching compares characters, not meaning, which is why it suits URL mapping better than tasks like internal linking. Similar slugs can describe different content, so check titles or content too.
• Redirect only to genuinely equivalent pages; Google treats irrelevant redirects to the homepage much like soft 404s.
• Keep redirects in place long term (Google recommends at least a year for site moves) and update internal links to the new URLs.
• Thresholds are judgement calls. Start strict and loosen with review.

Learn it on MLforSEO

• 404 and Redirect Mapping with Fuzzy Matching in Google Colab (Python)
• What Fuzzy Matching Is, and Where It Fits in SEO
• Automated Redirect Mapping with Triple Fuzzy Matching for Site Migrations (Notebook)
• Mapping 404 URLs to Live Pages with Fuzzy Matching (Guide)
• Fuzzy Matching for SEO Use Cases (Google Sheets Template)
• Introduction to Machine Learning for SEO (course)