A9 Algorithm

The A9 algorithm is Amazon’s product search ranking system, named after the retail subsidiary that built it. It decides which listings appear — and in what order — when a shopper types a query into the Amazon search bar.

How the A9 Algorithm Ranks Products

  1. Amazon matches the query to indexed keywords across your listing.
  2. It scores relevance based on title, bullets, description, and backend terms.
  3. It weighs performance signals: click-through rate, conversion rate, and sales velocity.
  4. It factors in price competitiveness, availability, and Prime eligibility.
  5. Results reorder continuously as new session data arrives.

Ranking Factors A9 Prioritizes

Factor Why It Matters
Keyword relevance Matches shopper intent to indexed listing terms
Conversion rate Amazon rewards listings that turn clicks into sales
Sales velocity Fast sellers rank higher for competitive terms
Price Competitively priced listings earn more visibility
Reviews and rating Higher star ratings signal buyer trust
Fulfillment method FBA and Prime-eligible listings often surface first
Image and copy quality Better assets lift CTR, which lifts rank

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