Amazon A9 Algorithm: complete guide & SEO Tips

Amazon's A9 algorithm seems like a big mistery for Amazon Sellers as there's not much official documentation on how it works. My goal with this guide is to demystify keyword relevance, sales velocity importance and conversion rate optimization in relation to A9, which are the key factors for rankings. I'll delve deep into SEO optimization components that you can leverage for your benefit for better natural rankings plus more golden nuggets based on Amazon A9's official patents.

Understanding A9

This algorithm also known as A10 is the cog that powers Amazon's search engine and on-page recommendations. It decides which products appear when a customer types in a keyword and, more importantly, in what order or ranking they appear.

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If you've got your sights set on prime ranking positions, then knowing how this beast works is crucial. A9 doesn't just focus on keywords but takes into account several other factors as well. High-performing ASINs are prioritized over those stuffed with irrelevant keywords. But remember – conversions are king here; the more relevant an item is to a search query (read: converts better), the higher it will rank.

Mastering this algorithm isn't easy. It's all about optimizing various components from titles and bullet points to descriptions and backend terms and, of course, generating more sales than your competitors in the same time frame. Conversion Rate is also key, so you need to be optimizing your listing every now and then. One strategy that usually works for my clients are AB tests, aka Amazon Experiments.

Now that we've unraveled some of its mysteries, let's delve into one of its key aspects – keyword relevance and sales velocity – where picking the right words can be your gateway to success on Amazon.

amazon experiments

Keyword Relevance

It's crucial to understand that stuffing your product listings with irrelevant keywords can do more harm than good. And, on the other hand, stuffing them with the same keywords won't make you any favour. As A9 was based on Google's core code (“The company licensed the Google search index but built on top of it” Brad Stone on The Everything Store) , it follows some Google's patents such as the reasonable surfer or behaviours and metrics such as pogo sticking, bounce rate or exit rate.

And, of course, it follows Google's indexing process: crawling, extracting keywords, indexing keywords for and ASIN and ranking those keywords.

amazon a9 indexation process

So, as Google does, A9's a ruthless gatekeeper; it swiftly penalizes those who attempt to game the system. Hence, ensure every keyword you use resonates with your product and its features. Actually, as the A9 team itself discusses in some papers, they have their own method to discover feature interactions on products: “Gradient boosted trees are our method of choice in ranking because they can discover complex feature interactions” (check Amazon Search: The Joy of ranking products, by Daria Sorokina, Erick Cantú-Paz)

Remember, Amazon prioritizes high-performing ASINs over keyword-stuffed ones. What does this mean for you? Your power lies in choosing relevant keywords and strategically placing them in your title, bullet points, description, and backend search terms. This not only improves your overall ranking but also increases conversions as customers are able to find exactly what they're looking for. As vital as keyword relevance is though, don't forget there are other components influencing your ranking on Amazon – like sales velocity. For more insights on keyword relevance, check out these best Amazon keyword tools.

Sales Velocity Importance

Let's shift gears and talk about sales velocity, a crucial metric that can make or break your product's ranking. This dynamic factor is the rate at which your product sells over a given time period on Amazon. It's not merely about how many units you sell; it also takes into account the speed of those sales. If you want to learn more about Sales Velocity, here’s an in depth video about this topic.

😱 How to RANK TOP 1 ON AMAZON with Sales Velocity

Here is an eye-catching table to give you a clear picture:



High Sales Velocity

Higher Ranking

Low Sales Velocity

Lower Ranking

Consistent Sales

Stable Rankings

Fluctuating Sales

Unstable Rankings

To dominate in this arena, you must maintain a high and consistent sales velocity. The algorithm favors products that consistently perform well over time, not just one-hit wonders. Consider running sponsored advertising campaigns to increase your sales velocity and also external Amazon campaigns, especialy on social high converting sites such as TikTok or Instagram.

Sales Velocity and rankings change every hour and are represented using Best Seller Rank, a ranking metric first used on 2016 on the patent Increases in sales rank as a measure of interest

,As we've discussed, mastering the A9 Algorithm isn't just about keywords – it's also about performance metrics like sales velocity. But don't stop here; there are other important components to consider for improving your ranking on Amazon. Next up: Conversion Rate Optimization – another game-changing element in the world of Amazon SEO.

Conversion Rate Optimization

Next on our radar is the all-important concept of Conversion Rate Optimization, a critical player in your product's success story. This is where the power comes into play. You need to take command of every single component of your listing and optimize it for maximum conversions. Your title, images, bullet points, and description – they all need to be honed with precision to convert browsers into buyers.

Let's not forget about reviews either. They carry enormous influence over purchasing decisions and, according to the 2021 patent Indexing and presenting content using latent interests are also used for keyword extraction and relate those keywords to the ASIN.

Systems and methods are disclosed for a system to provide an interface that is dynamic and that provides selectable links in response to a query for products in an electronic marketplace , where the selectable links are titled with the query and portions of reviews for products associated with the query

Make sure you're actively encouraging satisfied customers to leave positive feedback (both review feedback and Seller feedback).

And what about the price? Pricing is key and it needs careful consideration to strike the perfect balance between attracting buyers and maximizing profit margins. That's why I also recommend my clients to use an Amazon repricer, even when they're Private Label.

Don't underestimate inventory availability either; nothing turns customers away faster than an ‘out of stock' message blinking at them from their screens.

Finally, backend keywords are your secret weapon, helping Amazon connect your product with potential buyers searching for related items.

SEO Optimization Components

First of all, you need to know that Amazon A9 uses Google's information extracting techniques (we already discussed that at the beggining of this post) so that means there's a hierarchy. So the first extraction goes to the title of the product. This means the title is the most important SEO element. Then Bullet Points. Then Description and, finally, the backend keywords.


Long story short: start with your product title; make it compelling and packed with relevant keywords.

Images (for conversion, not SEO)

Images are equally crucial (for Conversion Rate, not SEO), so they should be high-quality and showcase different angles of your product.

Bullet Points

Your bullet points are not to be overlooked: they must clearly highlight key features while incorporating vital keywords.

Description / A+ / Enhanced Branded Content

The description or A+ content is an opportunity for storytelling: use this space wisely to inform customers about every aspect of your product. Introduce less relevant keywords and remember: A+ content is not extracted nor indexed by A9.

Pricing (for conversion, not SEO)

Price your products competitively, without compromising on profits.

Inventory (for conversion, not SEO)

Ensure inventory availability as consistent stock levels indicate reliability which Amazon values highly.

Backend keywords

Finally, backend keywords offer another chance to boost ranking by capturing additional search terms.

Reviews (for conversion, not SEO)

Fuel this power-driven optimization process with reviews that vouch for the quality of your products because nothing speaks louder than satisfied customers in the world of e-commerce.

Actually I've got this theory about reviews. They're not used for ranking, as you can find products with less reviews or even 0 reviews ranking on the first positions. That means that it all comes to Sales Velocity, as usual. Check this SERP for “cordless drill” and you'll find a 18 reviews cordless drill ranking better than others with as much as +5000 reviews

cordless drill seo

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Using Relevant Tools

As an Amazon seller, you have a wealth of resources at your disposal to optimize your listings and boost their visibility on search results. These tools provide invaluable insights into keyword relevance, sales velocity, conversion rates, among other crucial factors that influence ranking. Consider using:

  • Helium 10: Offers a suite of powerful tools to improve product listing optimization.
  • Jungle Scout Extension: A tool that estimates the number of sales needed to reach high rankings.
  • SellerApp: Provides comprehensive SEO optimization solutions tailored for Amazon sellers.
  • AMZScout Pro Extension: An all-in-one toolkit providing data analytics and insight into competition

Remember to consistently monitor performance metrics as they're key indicators of how well your products rank. And, please, don't shy away from tweaks and adjustments, it's part of the game! You're now better equipped than ever before and ready to conquer the world of e-commerce with confidence. The power lies within grasp; seize it!

Final Thoughts

Mastering Amazon's A9 algorithm is vital for your product's success. It prioritizes keyword relevance, sales velocity, and conversion rates over keyword stuffing. Enhancing your SEO components and using relevant tools like Jungle Scout Extension or Keyword Scout can significantly improve your ranking.

If you want to stay up on the game, I'd read the official A9 patents and, of course, experiment and AB test a lot. Read other experiments by other Sellers, keep an eye on the community, for example on the Amazon Reddit community and also the Twitter community.

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About the author

Avatar of Jordi Ordonez
Jordi Ordonez
Amazon and ecommerce Consultant at JordiobDotCom | Website

I work as an independent eCommerce and Amazon consultant.

Estrella Damm, Intersport, Bella Aurora, Lladró, Textura Interiors, Nice Things Palomas, Castañer, Due-Home and many other clients.

Lecturer & Teacher
I teach and have been a speaker at: Meet Magento, Prestashop, Prestashop Day, SEMRush, Cambra de Comerç Barcelona, ​​ClinicSEO, Ecommbeers, Ecommbrunch,, Ecommfest, EOI, ESIC-ICEMD, Foxize, Generalitat de Catalunya, Inesdi, Quondos and The Valley. In addition, I have done in-company trainings for brands such as Orange and Adidas.

I collaborate writing articles for Helium 10 blog, Shopify, SEMRush, La Vanguardia,, Marketing4ecommerce...

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