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Amazon’s A9 Algorithm: How to Optimise For It & What Makes it Tick!

If you’re interested in how to rank products in Amazon and haven’t heard of A9 before, you’ve landed in the right place.

When it comes to ranking a product in Amazon, we are at the mercy of A9 so understanding how it works is one of the most powerful bits of knowledge you can have.

Even if you’re already experienced at selling on Amazon and have ranked products before, this will still be a worthwhile read as we’re going into what A9 looks for, which is a powerful insight when it comes to optimising your products.

First, for the beginners:

What is an Algorithm?

The definition of an algorithm is:

a process or set of rules to be followed in calculations or other problem-solving operations, especially by a computer.

In other words, it’s a set of instructions that software follows in order to solve problems or reach desired outcomes.

Ok, got it?

So with that in mind:

What is the Amazon A9 Algorithm?


A9 is what Amazon calls their search algorithm.

If you want to simplify things further, you could call it the Amazon search engine.

This is the system that sorts all of the products on Amazon, prioritises them based on a variety of factors, and then offers them up to customers.

When you search for something on Amazon, the order in which the results are displayed is decided by A9 based on the search term you used, and what previous data suggests are the most relevant, attractive products for that search term.

It’s important to remember that Amazon is a business that wants to make money, and A9 will almost always throw up the results that have the best chance of making money for Amazon.

Essentially, the “instructions” for this particular algorithm are ranking factors, all of which are taken into account for every product, in order to allow Amazon to display the products in the correct order.

Keeping this in mind will make it a lot easier to understand why A9 makes the decisions it does and will help you to act accordingly.

Despite Amazon being one of the wealthiest companies in the world, they don’t put anywhere near the effort into updating and upgrading their search algorithm as Google do.

Why is this?

The simple answer is they don’t need to.

Google needs to be all things to all people, no matter whether you’re searching for products to buy, academic journals, niche blogs, or which episode of the Simpson’s that joke was in that you can’t seem to get out of your head.

This makes things get very complicated in terms of searcher intent, but Amazon has none of those problems since they already know your intent.

If you’re searching a keyword in Amazon, you’re looking to buy it, it’s that simple.


This means Amazon has less motivation to invest huge amounts of money into updating A9, and while regular tweaks are possible, (and nothing is technically impossible), we are less likely to see any huge, sweeping changes to how everything works than we are with Google.

Now that you know what A9 is and the factors it takes into account, let’s break down each of those factors and how to make the most of it:

Amazon A9 Direct Ranking Factors

First let’s take a look at the factors that have a direct and immediate impact on your ranking:

Availability (Current Stock Levels & OOS History)

This one is pretty obvious.

Amazon doesn’t want to rank products with inconsistent stock highly, because they have a higher chance of being out of stock at any given time, which means less sales overall.

Even worse, a user who searches, finds a product and tries to buy it but finds it’s out of stock, may never try again.

Serving up products with good stock levels and lesser past cases of stock running out means more orders for Amazon (and you!).

Action to Take

Consistency is key here so there are no immediate actions you can take, but we would recommend keeping a close eye on your stock levels and ordering more as early as possible.

A steady stock level and a lack of orders being cancelled due to stock issues is the only thing that will score you well here.

If you have a bad history of running out of stock, you will need to consistently avoid this for a while to get your rank back to how it should be.


Relevance is simply a question of how appropriate your product is for the keyword that has been searched.

Amazon is constantly collecting data on this, learning more and more about what users want with every search.

The most effective way for them to learn about this is sales.

If you’re trying to sell Vitamin C, but have also optimized your product to come up for the search term Vitamin B, nobody is going to buy your product simply because that isn’t what they’re looking for, and so it will quickly fall out of the search results.

In the same way, if a user searches a particular keyword, then purchases your product, your ranking for that keyword will go up as this order is telling Amazon your product is relevant to that search term.

Keyworx is the most reliable rank tracking software in the world and will make tracking this automatic, allowing you to easily and accurately rank multiple products at once.

Action to Take

Once your product is showing up on the first page; as long as it’s relevant, well optimized and priced well, this will take care of itself to an extent.

However, if you’re launching a new product, you may well be 10 pages back or more in the search results, which means you aren’t going to get any sales no matter how relevant your product is. When this is the case, Amazon sponsored products can help you get some appropriate orders and boost your ranking.

If you want a quicker approach, you can also purchase keyword focused sales from certain reliable Amazon SEO Consultants.

This involves real, unique people searching the keyword you want to rank for and purchasing your product, making it the quickest and most reliable way to rank a new product in the current A9 setup.


Image Source

Since Amazon want to make as many sales as they can, they try to offer users the most competitively priced products.

Not only will pricing your products too high have a negative effect on your ranking, but your sales will then decrease, making A9 think your product is less relevant and lowering the rank even more in a nasty circle of pain you want to avoid.

Action to Take

The obvious answer is to keep your pricing as competitive as you can. Keeping your price slightly below the average for the product type should not only keep you safe with this ranking factor, but make your products more attractive for buyers too, boosting your rank massively.

If you have too many products or too little time, you may find using a pricing automation tool helps, allowing you to set limits and then automatically updating your prices when necessary.

Those are the three direct ranking factors, but what about the indirect ones?

Let’s take a look:

Amazon A9 Indirect Ranking Factors

In addition to the above factors, the below indirectly affect your rank, but directly affect sales, which means, if you’re trying to maximize your rank and do everything you can to improve your position, for all intents and purposes these are just as important as the direct factors listed above.

Let me explain:

Selling Speed & Performance

All of the indirect ranking factors are focused on how quickly and how well your products sell (duh).

A good way to think of it is to think about conversion rates.

While conversion rates aren’t strictly a factor and there is no evidence A9 takes them into account, Amazon wants to offer it’s users the products with the best chance of selling, so optimizing your products for the best possible conversion rates can only increase your sales and therefore your ranking.

Action to Take

Taking the time to optimize your product descriptions, enhanced brand content, product titles, doing in-depth keyword research, and anything else you can do to make your product listings convert better will translate directly into additional sales and help your product to rank better in A9.

Unfortunately this one doesn’t come with a solid answer except “do everything right”, but the rest of the indirect ranking factors will all help to boost your sales, so continue onward and make sure you’re taking notes:

Review Quantity & Quality


This is perhaps the most self-explanatory of all of the factors besides relevance.

The more customers that have purchased your product and been happy with it, the more confident Amazon is about offering it to others.

Makes sense right?

It’s not just about having the best star rating, but the actual number of reviews matter too.

If Product A has one review at 5 stars, and Product B has 1,000 reviews for an average of 4 stars, product B will likely rank better since there is more reliability and social proof there.

Of course, social proof is one of the most reliable conversion techniques too, so this directly aids your selling speed and performance as well.

Action to Take

The obvious first step is to make your product the best quality it can be and ensure it is the solution your customers are looking for.

Negative reviews on your competitor’s products are a great place to learn more about what your customers are looking for and what makes them unhappy.

You can then use this knowledge to improve your product and avoid getting those same negative reviews.

Another great way to get reviews on Amazon is to send automated email follow-ups and/or include leaflets in the package that ask politely that customers leave a review if they’re happy, and request they get in touch first if they have any issues so that you can put them right (therefore cutting down on negative reviews as a knee-jerk reaction).


Once again, this comes back to Amazon maximizing their profits.

Amazon FBA products (or products that are stored in Amazon’s warehouse and fulfilled by them) are the products that make Amazon the most profit (outside of their own products).

Because of this, they get a ranking boost over products that are fulfilled by the merchant.

Action to Take

You should weigh up all your fulfilment options and never be afraid to fulfil your products yourself if it seems right to you.

After all, each seller is different and operates best with a slightly different set up.

However, if you want to maximize all of your ranking factors and get the highest possible rank you can, you should give Amazon what they want, and at least send some of your products in for them to handle.

It may seem unfair for this to be a factor, but it’s Amazon’s marketplace, and what they say goes.

Now, on to the last of the indirect ranking factors:


The better and more effective your imagery, the higher you will rank and the higher you will convert, both of which tie straight back into the selling speed rank factor.

There are two aspects to this, one is your regular Product Images.

The other is Enhanced Brand Content, which is a little different but just as important.

So what do you need to do to maximize the effectiveness of your images?

Action to Take

Your product imagery needs to be as clear and well photographed as possible, with good lighting, photos of all of the important features, and text stressing the benefits of these features, and the benefits of these benefits.

Find a good guide on photographing products and look at some of the most successful examples and you’ll be well on your way.

But what about enhanced brand content?

This is a feature that lets sellers fill in their product details section with images:

Looks a lot more convincing than a plain text product description, right?

Enhanced brand content has been found to increase conversions, and allows you to communicate a lot more information about your product to those who are willing to read it.

We will be bringing you a fully detailed guide to enhanced brand content very soon, but the key principles are the same as the product images:

  • Clarity
  • All features
  • Benefits of those features
  • Well photographed
  • Brand storytelling and alignment

Keep all of those in mind while creating your EBC, and you can’t go far wrong!

Keyworx Rank Tracking Software

After reading this article, you should have a solid understanding of what makes your products rank in Amazon.

We will be bringing in-depth guides to each of these factors, along with deeper dives into how you can use Keyworx’s browser-based automatic rank tracking features to grab hold of the first position and keep it.

Keyworx is the most powerful and easy to use rank tracking software for Amazon bar none, allowing you to automate rank tracking for all of your products and receive constant, immediate updates and insights on how to boost your revenue.