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How the Amazon A9 Search Engine Works

The number of businesses selling on Amazon is growing at warp speed. A massive shift occurred during the global Covid health crisis, when many brick-and-mortar sellers were forced to embrace an ecommerce business model. But that’s not the only reason. Amazon has a very low barrier to entry and features all the tools that sellers need to not only get started, but also develop their brand. It’s a fantastic, all-round platform. 

It’s not surprising that Amazon has become the biggest online marketplace ever. 

For sellers, Amazon’s size and popularity is bittersweet. On the one hand, the larger the platform, the larger the potential customer pool. On the other hand, the more sellers that are competing for visibility, the harder it is to get the right products in front of the right eyes. It can sometimes feel impossible to rank higher in the search results. 

However, as we all know, ranking and visibility are essential. After all, a customer cannot purchase your product if they can’t find your product. That’s why it’s so important for Amazon sellers to understand how to get their products seen. And key to that is exploring Amazon’s search engine, and the technology it’s powered by. 

The Importance of the Search Function

Search functionality has always been important to Amazon. However, it’s becoming increasingly vital today, at a time when the platform is undergoing a major transition.

This transition is being driven by changes in how sellers are using the platform. A few years ago, it was clear that Amazon was very much a sales platform. Today, however, more and more sellers are using it for awareness. In fact, research suggests that over half of all Amazon sellers are now using the platform to improve awareness and familiarity of their products, rather than just to sell them.

And so, the importance of the search function has been elevated. Amazon’s search feature now not only has to support users at the end of the buyer journey – at the decision stage – but also at the start of their journey, at the awareness stage. This means that Amazon can’t afford to take any risks. As such, the company has developed its own search engine, powered by industry leading A9 technology. 

What is the A9 Search Engine?

A9 is the name for the underlying technology that’s used to power Amazon’s own search engine. So, if you’ve ever typed anything into the Amazon search bar, then you will definitely have already used A9… you just may not have realized it! 

The A9 search engine is named after a leading US-based search and SEO company, A9.com, which was once part of the Amazon family. Even though it’s no longer Amazon-owned, A9 still plays a massive role in how the marketplace operates. 

Ultimately, what A9 does is very simple. When a potential buyer wants to find a product amongst the millions of products being sold on the platform, they enter their search queries into the field. A9 then works to analyze these search terms, and display products that it believes the user wants to see. The analysis part – the ‘how it works’ part – is a little more complex. We often think of search engines working by matching user search terms with keywords, but Amazon is a bit more complicated. 

How the A9 Search Algorithm Works

Algorithms are often kept under wraps. And so, while much of the A9 algorithm is shrouded in mystery, it’s generally accepted that it works in three different ways:

  1. By analyzing data
  2. By monitoring trends and traffic over time
  3. By indexing text across Amazon products

Using these three pillars, A9 assigns a ‘score’ to each product when a search query is made. This score determines two things: whether the item should be displayed for that given search, and where in the search results pages it should be, whether that’s right at the top of the first page, or further down the list on subsequent pages. 

The Amazon Search Results Page

The Amazon search engine results pages, or SERPs, are what you see when you type in a search query and hit the button; it’s a list of what Amazon determines to be the products that are most relevant to what you’ve asked to see. The SERPs are almost exclusively shaped by the A9 algorithm. Amazon’s end goal is, of course, to provide the very best experience for its customers. A happy customer spends money. And so making sure your products can be recognized by A9 is absolutely the key to success. 

Sponsored Products

There is only one way to ‘game’ the system, and that’s by using an Amazon PPC (pay-per-click) campaign like Sponsored Products. Sponsored Products ads are built on an auction model, which means sellers can bid to have their ads displayed in prominent and high-profile positions within the SERPs – and across other places – without having to tick all the A9 boxes. Imagine you’re selling a garlic press. A9 may determine your product to be the 50th most relevant product for that search term. But Sponsored Products is essentially a paid ‘fast pass’ to the front of the queue. 

However, sellers can’t rely on paid efforts alone. Every seller needs to ensure they’re paying enough attention to their organic efforts; those efforts that are going to naturally get them into highly visible positions in the SERPs, with the help of A9. 

Search Filters

It is important to remember that Amazon was built for buyers. Not sellers. Of course, it can’t be denied that Amazon’s seller interface and built-in sales tools are extraordinary. But at the end of the day, Amazon has one goal: to sell products to buyers. That means there must be tools for buyers to easily find what they want. Enter search filters. Filters allow buyers to drill down to what they want. Not just a garlic press say, but a chrome garlic press. Or a black garlic press. A9 needs to be able to take those filters and then hunt through products on sale to find the most relevant.

For sellers, building a deeper understanding of Amazon’s A9 algorithm is a fast track to developing a good SEO strategy that ticks all the boxes. 

The relationship between a search query and a URL

Amazon is smart. So are sellers. Some sellers figured out that ‘super URLs’ can help them game the system. A super URL is one which has key words at the end of the address and links directly to a product page. The clever bit is that this URL is shared around the web in order to make Amazon think that the clicks all came from the search results, thus giving the product in question a boost in the SERPs. The bad news? A9 is smart, too. It knows that some sellers use ‘Super URLs’ to get better rankings so all those clicks could actually get you banned, not boosted. 

What is Amazon SEO?

‘SEO’ stands for ‘search engine optimization’, so ‘Amazon SEO’ simply means to optimize products and processes for Amazon, and for its A9 search algorithm. 

‘Optimizing’, in terms of SEO, means to take measures to help your chosen search engine recognize and understand your offering, whether that offering is a product, a piece of content, or anything else. When the search engine understands what you have, it’s in a better position to deliver this to the most relevant, high-quality users. 

SEO is probably something you’ve encountered before. But due to how A9 works, Amazon SEO is a little different to Google SEO. It all comes down to user intent. 

SEO & User Intent

User intent is exactly what it sounds like: it’s the intent or goal of the user. Now, when a person uses the Google search engine, their intent could literally be anything. To go back to our previous example, if they were to type in ‘garlic press’, they could be wanting to buy one. They could be wanting to learn how to use one. Or understand how to clean it. They may want to know when it was invented. Google users have very diverse intentions. But can we really say the same for people using Amazon?

Not really. 

While Amazon is increasingly making a name for itself in the awareness space, it’s still not the ‘go to’ place for those who are only just discovering that they have a problem that needs resolving. They are, however, the ‘go to’ place for those who have an idea of how to solve their problem and want to purchase a solution. 

Of course, they may not even know what that solution is just yet. But it seems reasonable to assume that, if they’re searching Amazon, they’re in the market to buy. And so, Amazon SEO is heavily commercial; it’s rooted in the concept of sales. 

This means that developing an SEO strategy for the sales based A9 algorithm looks a lot different to developing an SEO strategy for practically any other search engine. 

That’s why we’ve created this helpful guide, making it easy to understand the most powerful and effective ways to optimize your approach for the A9 search algorithm.

Amazon Ranking Factors

Earlier on, you may remember that we mentioned how search engines are typically closely associated with keywords. We often think of search engines working by matching user search terms with relevant keywords. But due to A9’s sales-focused nature, Amazon is different. Amazon considers a wide range of ranking factors when calculating a product’s SERPs ‘score’, which can be broken down into 2 categories:

  1. Performance factors
  2. Relevance factors

So… let’s dig a little deeper…

Performance Factors

A9 cares about performance because Amazon cares about sales. Amazon naturally wants to sell products, so it’s keen to prioritize products that are likely to sell – or have already demonstrated an ability to sell – when assigning a SERPs score for products. 

Some of the biggest performance-related ranking factors include…

Sales performance history

Statistically speaking, products that have performed well in the past are likely to perform well in the future. Therefore, A9 closely considers sales velocity when determining rank. Quite simply, the more products you sell, the more ‘points’ you get from the A9 algorithm. There is one small frustration with this: that it’s difficult to earn those ‘points’ when you’re dealing with a new product. In this instance, it can be worth running some PPC campaigns or signing up for schemes like the Amazon Early Reviewer program to get some sales under your belt in a very short period. 


Price is a huge consideration for A9. Set your price too high, and you’re setting up a big obstacle that gets in the way of people purchasing your product, which has a knock-on effect on your sales performance history. Set your price too low, and customers may question the quality of the product, again imparting overall sales. Pricing is a tricky line to walk. The best thing to do in this instance is to conduct a competitor analysis, find other brands like yours, selling similar products, and see how they’re pricing their products. Remember: when it comes to ranking, it’s all relative. 

Product availability

This may sound obvious, but it’s something a lot of sellers overlook you can’t sell – and you can’t achieve high levels of performance – if your products are never in stock! When you run out of stock, potential customers turn elsewhere, improving the sales history of your competitors, and helping them climb the ranks. If you struggle with stock, it’s worth considering the Fulfilled by Amazon scheme, or Amazon FBA. Signing up for this program means you send stock to Amazon in advance, and they manage sales, shipping, and inventory on your behalf. It’s worth a look. 

Product reviews

Reviews don’t have a direct impact on performance. But they do have a huge effect on how potential buyers perceive your brand and, therefore, the likelihood that a potential customer will buy. So, they can be thought of as a performance-related ranking factor. Peer-generated content such as reviews have become a ‘go to’ source of information for buyers thinking about making a purchase. And they’re pretty powerful. If your review profile isn’t quite as populated as it could be, working to generate more feedback is a smart move. 

Product images

In terms of A9, product images are handled in much the same way as customer reviews; they don’t have a direct impact on performance, but they do have an impact on customer perception and, subsequently, on motivation to buy. Product images – especially the image you select as your main image which is displayed in the SERPs – also have an impact on clickthrough rates, which is a metric that supports performance. Always add product images to your listings. And where possible, add multiple images to help potential buyers understand your item more. 

Relevance Factors

A9 cares about relevance because, at the end of the day, it’s still a search engine! Performance metrics matter for the commercial side of A9. But A9 is still a search engine, and ultimately it wants to deliver results which are most relevant to the user. 

Some of the biggest relevance-related ranking factors include:


The most obvious relevance-related factor is, of course, keywords. Both long tail and short tail. Keywords are at the very heart of SEO. As a seller, you need to make sure that the search terms your audience are likely to use are the same keywords that you are incorporating into your product listings, in your titles, descriptions, and more. For example, back to the garlic press, customers may be using terms such as ‘press’, ‘crusher’, or even ‘masher’. By using ‘press’ alone, you’re preventing yourself from being displayed for those using other search terms; you’re missing out on visibility. 

Backend keywords

Backend keywords are every seller’s secret weapon. The type of keywords we’ve looked at above are what’s known as ‘frontend’ keywords; they’re the keywords that are added into places where your customers can see them. Backend keywords are added into your listing settings and are not visible to customers. This makes them ideal for SEO. It means you can provide A9 with deeper information, even if you don’t necessarily want your customers to see that information. Anything relevant that doesn’t fit into your customer-facing content can be added to the backend. 

Product title

As already discussed, the A9 algorithm analyzes data when it’s assigning a ‘score’ to each product for ranking. The data it uses is found all across your product listing, including the title. Therefore, it’s important that your title not only attracts potential customers, but also accurately informs A9 about what your product is. Titles should be keyword-rich, and where possible contain your brand name. However, Amazon recommends that titles should be around 60 characters only, so you’ll need to find that happy middle ground between being concise and being descriptive. 

Product Description

Once again, product descriptions can be used to provide the A9 algorithm with information about your product. However, with a description, you have much more opportunity to present this information than you would with a limited character title. The challenge with descriptions, though, is that you need to walk the fine line between writing for people – your target customers – and writing for machines – the A9 algorithm. It’s important to write in a way that engages your customers, answers their questions, and motivates them to buy, but which also efficiently informs A9. 

Product features

When listing an item on Amazon, you have the option of adding bullet points into the listing. These are separate from your description, and act as a way of highlighting a few specific features or functions to catch the eye of buyers who may just be scanning the information. However, they can also be used to catch the ‘eye’ of the A9 algorithm, too. By adding strategic keywords into your bullet points, you can once again inform A9, and help it to make the best product ranking decisions, prioritizing your listing for searches that most closely align with what you’re offering. 

The Flywheel Effect

The flywheel effect occurs when you put effort into achieving something, which then itself drives more power into achieving that thing again, and again, and again. Once the wheel is in motion, the results continue to be generated. That’s exactly what happens when you combine performance and relevance-related factors. 

What we mean by this is that, when you focus on optimizing relevance-related ranking factors, you’re naturally improving visibility in the SERPs, and therefore generating more click throughs and, subsequently, a better conversion rate. And, as we know, the more you sell, the better A9 considers your performance to be.

At the same time, the more you sell – the higher your sales velocity – the more you generate customer reviews, and the more you’re able to demonstrate a connection between your brand and your customers. And, as we already know, these are things the algorithm looks for, rewarding you with greater visibility and a prominent position. 

One powers the other. And they keep on powering each other. 

Final Thoughts

If you’re keen to gain – and maintain – a strong position in the Amazon SERPs, and keep improving conversion rates, it’s essential you understand A9; what it is, what it does, how it works, and how to build an Amazon SEO strategy that’s optimized for it. 

This guide should help you achieve just that. However, one thing to keep in mind is that A9 is an ever-evolving technology. It’s constantly being updated to ensure that Amazon is always delivering the most relevant results – and most positive experience – to its customers. SEO isn’t a one and done kind of deal. You’ve got to be prepared to stay on top of it and keep working away at it for maximum impact. We’re here to help. Reach out if you’d like to chat about how we can help. 

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