Amazon’s A9 Algorithm And Everything You Need To Know

A9 originally operated as a traditional search engine conducting web search results but also product search results on Amazon.
Written By Laura Meyer
Published on July 11, 2019   |7 minute read

Amazon: The Search Engine

To the average consumer, Amazon is a retailer. To the experienced seller, Amazon is the largest e-commerce search engine. Understanding Amazon’s A9 Algorithm, what influences a product listing appearing on the first page vs the fifth page, is the most important element to selling.

According to emarketer, “46.7% of US Internet users started their product searches on Amazon,” in comparison to the 34.6% who went to Google first. In order for a brand to properly utilize Amazon, its products must be visible for all relative search queries.

A9 Background

A9 originally operated as a traditional search engine conducting web search results but also product search results on Amazon. When A9 debuted in September 2004, Google had only been incorporated for six years. Needless to say, search engines were still a very new concept. 

Today, A9 still operates as a subsidiary of Amazon. However, instead of conducting web searches, the power of the algorithm all product searches and advertisements served on Amazon. 

What is Amazon’s A9 Algorithm

Amazon’s A9 algorithm is a ranking system influencing product placement on the search engine results page (SERP) for a given keyword phrase. 

In 2003, Amazon created an independent company aimed at producing technology for searching and advertising. Contrary to popular articles, Amazon’s A9 Algorithm is not just a single algorithm powering the retail beast. Developed by Ph.D.’s and seasoned professionals, the A9 Algorithms are designed for customers to feel like it’s reading their minds. 

Amazon puts a strong emphasis on the customer experience. Therefore, the algorithm is designed to link relevance between a customer’s query and the indexed products. The relevancy score has a twofold effect:

  • Where a product is ranked organically,
  • Impressions served through paid advertising.

The A9 Algorithm indexes millions of products worldwide, and reflects price and inventory changes in real-time to return relevant results in milliseconds. The result: indexed products presented to customers the Algorithms think they need or will purchase.

The Four Key Influencers to rank Organically on Amazon 

The four key influencers to organically rank on Amazon are Text Match Relevancy, Price, Inventory, and Sales Velocity. 

While these four elements hold the most weight in Amazon’s organic rank, this isn’t to say other factors don’t contribute as well. 

Text Match Relevancy 

A strong keyword strategy is arguable, the most important element to gaining traction on Amazon. Without a keyword strategy and implementation, a brand/product will not get the most out of Amazon.

For example, consumer A searches, “Head and Shoulders” and purchases their dandruff shampoo. The brand was able to capture that sale because of brand influence driven outside of Amazon. Now, consumer B searches, “dandruff shampoo,” and opts to purchase Head & Shoulders. The sale is much more powerful and incremental than a brand-driven sale. 

The point is: that established brands can still have strong sales on Amazon without a keyword strategy. However, if those same brands were to implement a strong keyword strategy their sales would grow exponentially. 

How To Improve Text Match Relevancy:

  1. Research what customers are searching to discover your product or one like it. At Envision Horizons, we use subscription software tools to identify monthly search volumes, the number of competing products, and PPC cost. However, there are plenty of free software tools sellers can use as well. 
  2. Input target keywords into the product title, bullet points, description and backend keywords. According to our experts, the product title holds the most weight for improving the visibility of a keyword. 
  3. Double-check that the product is indexed for all the target keywords. While Envision Horizons use subscription software for this as well, the easiest free way to check is by manually searching the ASIN with the keyword or phrase on Amazon. 


Envision Horizons works with a number of luxury brands and this element can sometimes get a bit tricky. Amazon has a misconception about being a discount retailer. Realistically, the Amazon customer shops for value, not price.

If a customer searches for face cream, the algorithms are going to show competitively priced products. A La Mer face cream (2oz retails for $325) will never be on the first page for a generic search like face cream. This is because the price doesn’t appeal to the average consumer.

Where a higher price is expected for products that can be categorized as luxury pricing, we strategize very specific keyword phrases. In the example of beauty, we highlight specific ingredients such as “hyaluronic acid face cream” or the target customer “anti-aging face cream for women.”  

Another price strategy we often employ for products with variations is to promote the lowest price variant. For example, if a protein bar sells in six packs and 12 packs, we exclusively push the 6 pack. Then, we use the product detail page and value pricing as an opportunity to upsell. 


If a product goes out of stock, it will no longer show up in the SERPs until replenished. The A9 algorithms will punish a product until it has consistent inventory health. 

The best way to combat inventory health issues is by monitoring daily and weekly sold averages. Envision Horizons experts use automated software to monitor daily, weekly, and month average units sold to compare what we have in stock.

Sales Velocity

In order to achieve strong sales velocity, you have to sell quality products people need and are searching for. Outlined are the contributing factors to a product’s conversion rate. 

ImagesDepending on the category we recommend each product detail page has five images and a video that is under 30 seconds. A 2015 press release from Amazon, states nearly 70% of Amazon customers placed an order on a mobile device. There is no question this number has increased and on the mobile experience, the images are the biggest selling point. Images should tell the brand story, highlight key features/ingredients, and how to use the product and lifestyle. Read more about how to make your imagery stand out on Amazon here.

EBC/A+ Pages: Similar to imagery, EBC/A+ content becomes more important as mobile shopping continues to become more prevalent. According to Amazon marketing material, EBC/A+ content can increase a product detail page’s conversion rate by three to five percent.

Customer Reviews: A product must have 15 reviews averaging above a 3.5 average star rating in order to be considered “retail-ready”. However, studies suggest 70% of Prime customers will NOT buy a product below 4.5 stars if there is a similar product with a higher rating. 

External Traffic

Amazon rewards product detail pages that send external traffic to Amazon. Major publications and influencers use Amazon’s affiliate program. Typically, they’re paying those partners up to 10%, making selling a product into a gift guide or listicle very lucrative. 


Similar to external traffic, utilizing Amazon Advertising is going to increase visibility and sales velocity. When launching a new brand or product we build out a time period where we aggressively gain momentum through advertising. During this time, we operate at a slim margin in exchange for gaining a strong organic rank. Our experts have seen firsthand the advantages of keeping high-volume keywords live, even if the ACoS is above goal. The idea of this is that the exposure increases overall ranking. Additionally, Envision Horizons has a dummy account where we’re able to put these theories to the test. This is where our hypothesis proved correct.


In sum, there are a variety of factors that make up the algorithms. While experts may never fully understand all of them, the four influencers are a great place to start. 

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