Reviewed by the SEOPointz team · Last reviewed June 2026. Amazon never publishes its ranking formula, so we describe only mechanics that current seller documentation and field-tested practice support — and flag where the “A9 vs A10” debate is informal naming rather than official terminology. SEOPointz may earn a commission from some links; it never changes what we recommend.
Most Amazon sellers chase the wrong thing. They obsess over stuffing keywords into the title and forget that Amazon’s entire business is built on showing shoppers the product most likely to be bought and kept. Get a listing indexed for the right terms and then prove it converts, and ranking follows. This guide explains how Amazon’s search engine — commonly called A9, with sellers using “A10” to describe its newer, more buyer-focused behaviour — actually decides who shows up first.
From A9 to “A10”: what really changed
“A9” is the long-standing name for Amazon’s product search algorithm, and early on it leaned heavily on two things: keyword matching and raw sales velocity — the more you sold, the higher you ranked. The shift sellers now label “A10” isn’t an officially announced product; it’s shorthand for a smarter, more customer-obsessed version that weighs relevance and satisfaction, not just volume. In practice that means conversion quality, organic engagement and seller reliability count for more than they used to, and brute-force PPC counts for relatively less.
Conversion rate is the factor that moves the needle
If you optimise one thing, optimise the percentage of clickers who buy. Conversion rate is the strongest lever in the modern algorithm, because it directly tells Amazon that shoppers searching a term are satisfied by your product. A listing with a 12% conversion rate will out-rank a heavily advertised listing converting at 4% for the same keyword, often while spending less. Price competitiveness, a clean main image, review count and rating, and Prime eligibility all feed conversion, which is why they show up on every ranking-factor list — they’re upstream of the metric Amazon cares about.
Indexing comes before ranking: the technical fields
You cannot rank for a keyword Amazon hasn’t indexed you for, so the listing fields do real work:
- Title — up to 200 characters in most categories, but mobile often shows only the first ~70–80. Lead with brand and the core keyword phrase a shopper would type, then qualifiers.
- Bullet points — typically five at up to 500 characters each, though only roughly the first 1,000 bytes across all bullets are indexed for search. Front-load benefits and secondary keywords; keeping each bullet under ~200 characters also prevents mobile truncation.
- Backend search terms — the US limit is strictly 249 bytes, measured in bytes, not characters. Go one byte over and Amazon can silently de-index the entire field, so use it for synonyms, misspellings and alternate phrasings — never repeat words already in your title.
The 2026 emphasis: organic and external traffic
The clearest modern shift is that Amazon rewards demand it didn’t have to pay to generate. Organic sales tend to lift rankings more than the equivalent PPC sales, and traffic you send from Google, social media, email or influencers signals that the product has real pull. Driving qualified outside traffic to a listing that then converts is one of the few ways to break a new product out of the cold-start problem — just make sure the external clicks actually buy, or you depress the conversion rate you were trying to build.
Seller authority quietly gates everything
Account health is a ranking input, not just a compliance checkbox. Strong feedback scores, a low order defect rate, reliable fulfilment and responsive customer service all support visibility, while late shipments, defects and policy strikes can suppress it. Reviews matter here too — both their count and their quality — alongside engagement signals like time on the page. None of these replace a good product and a competitive price, but they decide whether a good listing reaches its ceiling or gets capped below it.
Where to spend your attention first
| Lever | Primary effect | Notes |
|---|---|---|
| Main image & price | Conversion / CTR | Biggest, fastest impact on the metric that ranks you |
| Title keyword placement | Indexing + relevance | Brand + core phrase first; mobile shows ~70–80 chars |
| Backend search terms | Indexing reach | 249-byte hard limit; over it de-indexes the field |
| External + organic traffic | Ranking lift | Weighted above equivalent PPC if it converts |
| Account health | Visibility ceiling | Defects and late shipments suppress rankings |
Frequently asked questions
Is the “A10 algorithm” an official Amazon update?
No. Amazon calls its search system A9 and has never announced an “A10.” Sellers coined A10 to describe its evolution toward conversion, organic traffic and seller reputation. The behaviour is real; the name is community shorthand, so treat any source quoting exact “A10 weights” with healthy scepticism.
Does running more PPC improve my organic rank?
Indirectly and temporarily. Ads create sales velocity and visibility that can kick-start a listing, but the durable ranking comes from conversion and organic demand. PPC that drives poorly-converting clicks can actually hurt by dragging down your conversion rate.
How many keywords should I put in the backend search terms?
As many distinct, relevant terms as fit inside 249 bytes — and not one byte more. Skip words already in your title, drop commas (they aren’t needed), and fill the space with synonyms, misspellings and alternate phrasings.
Amazon is one surface; the same product can and should rank on your own store in Google too. To carry these principles to your site, read our guide on how to rank individual product pages in Google, and to sharpen the titles that drive clicks on every channel, see product title optimization and naming conventions.
