A9

Amazon & D2C glossary · Harpy Media

A9 is the search-and-ranking algorithm that decides what a shopper sees when they type something into Amazon. It matches the query against catalog data — your title, bullets, backend terms, attributes — and then orders the matches by how likely each one is to actually sell. Relevancy gets you into the race; performance wins it.

What is A9?

A9 is the search-and-ranking algorithm that decides what a shopper sees when they type something into Amazon. It matches the query against catalog data — your title, bullets, backend terms, attributes — and then orders the matches by how likely each one is to actually sell. Relevancy gets you into the race; performance wins it.

Everything organic on Amazon runs through this machine. Rank well and your customer acquisition cost collapses, because traffic arrives free. Rank on page two and you either pay for ads forever or don’t get found at all. That’s why A9 isn’t an SEO curiosity — it’s the rent on your entire storefront.

The two pillars: relevancy and performance

Before A9 can rank you, it has to understand what you are. It reads your listing text and structure to index you against queries — miss the language your buyers use and you’re invisible no matter how good the product. Once you’re relevant, the ranking race is performance: sales velocity, conversion rate, price competitiveness, fulfilment speed. A9’s job is maximizing revenue per search, so it promotes listings that convert shoppers into buyers.

A conceptual ranking model

Nobody outside Amazon knows the exact weightings, but operators work from a useful approximation:

Fulfilment quietly moves the whole curve

FBA listings carry the Prime badge, and Prime converts — faster shipping, easier returns, more trust. Because A9 rewards conversion, the fulfilment advantage compounds: FBA listings convert better, so they rank better, so they sell more, so they rank better again. FBM sellers aren’t locked out, but they need to be excellent everywhere else — imagery, price, reviews — to neutralize the badge advantage.

The honeymoon window

For roughly the first 30–45 days after a new ASIN goes live, A9 has no performance history on it — so it gives the listing an artificial boost to gather data. Every sale in that window is weighted heavily. Passive launches waste the window; focused launches — exact-match keywords, aggressive but disciplined PPC, full inventory — use it to bank the early velocity that carries rank for months.

In practice

A brand launching a stainless-steel garlic press loads the title and bullets with the exact phrases buyers search, launches aggressive exact-match PPC on day one, and keeps stock deep for the full honeymoon window. Two weeks of concentrated sales register as strong velocity and conversion; A9 promotes the listing onto page one for its main term, and organic orders start arriving at a cost of zero.

How Harpy Media helps

Ranking is our core work: keyword architecture written from real search data, listings engineered for conversion, and launch sequencing that uses the honeymoon window instead of mourning it. If you’re stuck on page two, this is the problem we solve.

A9 FAQ

How does the A9 algorithm work?

It matches queries to listings through text relevancy, then ranks matches by performance — sales velocity, conversion, fulfilment speed, price — to maximize revenue per search.

How do I rank higher on Amazon?

Write listings in the language of real searches, drive early velocity with focused PPC, convert well with strong images and price, keep stock deep, and deliver fast — FBA makes the last part easy.

What is the difference between A9 and A10?

“A10” is industry slang for A9’s evolution — heavier weighting on external traffic, seller authority, and organic (non-ad) conversions. Amazon still calls the system A9.

Does price affect my ranking?

Indirectly but powerfully — price drives conversion, and conversion drives rank. A premium price without premium differentiation bleeds conversion and drags the listing down.