Key takeaways
- A10 weighs sales velocity and conversion, not backlinks. Rank what converts, not what reads well.
- Indexing field weight: title > bullet 1 > bullets 2-5 > description > backend.
- British-English variants index separately from US spellings — "colour" and "color" are two different keywords.
- Validate any SEO change with 14 days of held-constant data on unit session percentage.
Amazon SEO is one of the most misunderstood disciplines in e-commerce. Marketers arrive from Google SEO and assume that backlinks, content depth, schema and authority are the ranking factors. They are not. Amazon's A10 algorithm ranks the listings most likely to convert a query into a sale, weighted by sales velocity, keyword relevance, conversion rate, in-stock rate and a basket of customer behaviour signals. Optimising for that is a different discipline.
How A10 actually ranks
A10 is the current iteration of Amazon's organic ranking algorithm. The exact weightings are not published, but the order of importance is consistent across every dataset we have ever seen on UK listings:
- 1Sales velocity for the keyword — how often this listing converts when shown for this term.
- 2Keyword relevance — does the listing actually contain the term in indexed fields.
- 3Click-through rate from the search results page — does the title and main image earn the click.
- 4In-stock rate — out-of-stock ASINs are deprioritised even after they restock.
- 5Customer behaviour — verified reviews, return rate, customer service feedback.
What A10 explicitly does not care about
Backlinks. Domain authority. Off-Amazon traffic (except as a sales-velocity input via Brand Referral Bonus). Word count. Reading time. Keyword density beyond indexing.
Indexing field weight — where keywords actually count
All five indexable fields are not equal. A keyword in the title carries multiples of the weight of the same keyword in the backend. A common failure mode is stuffing backend with terms that should have been in the title — they get indexed but rank weakly. The hierarchy:
- 1Title — strongest weight; first 60 characters strongest of all.
- 2Bullet 1 — second strongest; treat as a continuation of the title.
- 3Bullets 2-5 — moderate weight, declining slightly with position.
- 4Description / A+ Content — indexed but at lower weight.
- 5Backend search terms — 249 bytes total; for terms that genuinely cannot fit elsewhere.
Read: Amazon Keyword Research for UK Sellers — Practical Methodology →
Read: Amazon Title Optimisation 2026 →
British-English is its own keyword universe
Amazon UK indexes "colour" and "color" as different keywords. The same applies to "organise/organize", "trousers/pants", "hoover/vacuum", "nappy/diaper", "pram/stroller". Listings written in US English may rank for British buyers searching the US spelling, but they will lose ground to competitors targeting the British variant directly. Use British spellings throughout, with high-value US variants only in backend if budget allows.
Mobile-first conversion is part of SEO
Over 70% of UK Amazon traffic comes from mobile. The main image, first 60 characters of the title, price and Prime badge are all the buyer sees on the search-results page. Conversion at this point feeds directly back into A10 ranking. SEO that ignores mobile presentation will rank well briefly and then decay as conversion data lands.
Read: Amazon Main Image Compliance 2026 →
How to validate an SEO change without losing rank
Amazon does not allow A/B testing on titles via Manage Your Experiments for most ASINs, so the only safe validation method is rolled-out comparison: change one variable, hold everything else constant for 14 days, compare unit session percentage and impressions. If unit session percentage moves more than ±0.8 points and impressions are stable, the change worked. If impressions move and unit session percentage does not, you changed indexing without changing conversion — which is rarely the goal.
SEO is phase two of the wider growth model:← Back to the Amazon Growth pillar
