How the Amazon A9 Search Engine Works


If you’re selling on Amazon, then you’ve probably already realised that you’re not the only one to have that idea. The Amazon platform is the biggest online marketplace in the world, and there are – quite literally – millions upon millions of products available to purchase through the website. Some of them are from Amazon themselves, and others are from third party sellers just like your business. 

Such a massive digital environment simply couldn’t exist without a search bar. Imagine trying to find a specific cushion on Amazon through browsing alone. Could it be done? Yes. Would it be frustrating working your way down – manually – through each subcategory until you found what you were looking for? Yes. Search is vital. 

The Importance of the Search Function

The most important thing to understand about search is that it’s not just the concept of search itself that’s critical; it’s about the overall quality of the search function. That’s because search is quite complex, and there are two sides to it: there’s the customer-facing side of search, and there’s the business-facing side of search. 

From a customer perspective, the search function must be able to make it easy to find a product. From a business perspective, the search function has got to go some way towards building – and maintaining – customer relationships, satisfaction, and loyalty. It does that by creating a positive experience. That comes from delivering the best results. 

So, it’s clear that Amazon search can’t afford to be anything less than perfect. And that’s exactly why Amazon uses its own custom search engine, known as ‘A9’. 

What is the A9 Search Engine?

The A9 search engine is Amazon’s own algorithm that is designed to achieve the two business critical tasks discussed above: helping customers find products easily, and delivering the best, most relevant results to meet needs and expectations. 

A9 is named after a search technology leader once owned by Amazon. 

On the surface, A9 is much like other search engines such as Google Search or Microsoft Bing. Ultimately, it’s designed to determine which products are displayed for what search queries, based on the product ranking algorithm built into the technology. 

That’s the simple explanation. But there’s a bit more to it, as we’ll explore below. 

How the A9 Search Algorithm Works

Asking how the A9 search algorithm works is a little like asking how the Google ranking algorithm works. The companies are remarkably tight-lipped over the precise ins and outs of the calculations they use, and the degree of importance assigned to each possible ranking factor. Staying mum prevents users from playing the system. 

We can, however, assume that the A9 algorithm isn’t quite as complex as Google’s. It simply doesn’t need to be. Google handles queries from shoppers at all stages of their journey, whereas Amazon primarily handles queries from those ready to buy. We’ll talk more about that later when we take a closer look at Amazon SEO as a whole. But for now, we can use this to get more of a feel for the A9 algorithm. 

We can also assume that the A9 algorithm impacts numerous factors across the Amazon website. The four biggest areas where its efforts are likely seen include:

1. The search result page

Amazon’s A9 algorithm works to determine which products are featured on the search results page for a particular query. It also decides where each product ranks in comparison to other products that also made the cut. Essentially, A9 is responsible for the ordering of the products. 

2. Sponsored Products

A9 is also understood to be responsible for the placement of products being advertised through a Sponsored Products campaign. It determines whether Sponsored Products are at the top of the page or combined with organic results. 

3. Search Filters

A9 will also work to determine the most suitable Amazon ranking and search results position for products, based on various search filters which may be applied by the user. This could be anything from colour and size to brand name, review, price, and more. 

4. The Relationship Between a Search Query and a URL

When you think about a product page’s URL, you might not think that it has much to offer. However, Amazon URLs tell Amazon a lot about the page. The URL will often contain keywords which signpost what a product is about. That insight can be applied on top of all the other information already gathered to ensure shoppers are being shown products they are actually searching for. 

Really, the A9 algorithm works by assessing whether an Amazon product should rank higher – or rank lower – than a competitor product. This decision is based on what that particular user is looking for. It determines whether a listing is worthy of a first page position, or if it’s not. 

However, the underlying driver of the A9 algorithm is, of course, Amazon SEO. Without SEO – without Amazon sellers optimising their listings and feeding vital information to the tool – A9 can’t do its job. So, it’s really all about Amazon SEO. 

What is Amazon SEO?

Amazon SEO is simply search engine optimisation through the Amazon platform. 

Search engine optimisation means optimising or fine-tuning your product listings and backend campaign settings to ensure that the A9 algorithm has access to all the vital information and data it needs to rank your products accurately and effectively. 

Search engine optimisation is, at the end of the day, the key to forming that all important connection between what your target customers want, and what you’re offering. It’s also the key to ensuring those customers can find your products quickly. 

If you have your own business website, or if you’ve been selling your products online through other channels, then SEO probably isn’t an entirely alien concept to you. You’ve probably come across the need for SEO when improving your Google rank. 

But Amazon SEO is different. 

Amazon Ranking Factors

As we briefly touched on earlier, Google handles queries from across all stages of the buyer journey. It’s there at the awareness stage, when customers are only just realising that they have a problem that needs to be solved. It’s there at the consideration stage when customers are evaluating the options available to them. And it’s there at the decision stage when customers are selecting a solution. 

Amazon isn’t like that. It’s certainly a consideration platform. And it’s definitely a decision platform. And while the Amazon of today is much more of an awareness platform than it once was – especially with the introduction of new awareness features like enhanced Store pages and ‘Posts’, for example – it’s still not the first place that a customer is likely to head to when they want to carry out research. 

So, unlike Google, Amazon SEO isn’t rooted in search intent. We already know what that intent is: to buy. Amazon SEO is more rooted in the commercial side of things. But that being said, it’s not just commercial keywords that the algorithm considers. 

A9 & Keywords

Keywords are the heart of SEO, and naturally play a huge role in how the A9 search engine works. After all, SEO is about matching a user’s search term with the search terms that are used to describe a product. Naturally keywords are going to have a part to play here. This means that, as a seller, you’ll need to ensure that you’re incorporating relevant keywords across various parts of your descriptions and campaigns. 

Conducting keyword research to better understand what your target customers are searching for is important. And it’s equally important to conduct research into what your target customers are searching for at the decision-making stage. This will be different to what they’re searching for at the awareness stage or at the consideration stage. 

The general advice here is different to the general advice you may get when adding keywords for Google. Commercial keywords and sales keywords have a place. When you’re selecting keywords for Amazon, don’t overlook the importance of long-tail keywords, or high purchase intent keywords. Don’t stick to short-tail keywords alone. 

Looking Beyond Keywords

Up until this point, with the exception of the sort of keywords that should be used, you’re probably thinking that Amazon’s A9 algorithm sounds pretty similar to Google’s algorithm. And overall, it is. But there’s one massive, hugely significant difference between the two. And this is where a lot of Amazon sellers fall flat. With A9, keywords are important. But they’re just one part of the overall story. 

Of course, Google isn’t just keyword based, either. If you search for ‘Google ranking factors’, the general consensus is that there are over 200 different elements that are taken into account. Keywords, however, are at the top of the list. 

With A9, keywords don’t have quite the same power. They’re still important. But A9 places quite a bit of importance on other non-keyword factors. This is because Amazon isn’t just about getting the right products in front of users eyes; it’s about encouraging them to buy. That’s how Amazon earns a healthy profit, after all. 

If a user searches for ‘shower gel’, for example, Google’s goal is to provide that user with as much information about shower gel as possible. To do this, it relies heavily on keywords. It gives a better ranking to websites featuring the keyword ‘shower gel’. 

Amazon’s goal is different. Amazon’s goal is to get that user to purchase shower gel. Keywords alone aren’t enough. If keywords were the only factor – or the most valuable factor – then almost equal importance could be assigned to two shower gel products: one that was very likely to sell, and another that was unlikely to sell. 

This is detrimental to Amazon. The platform obviously doesn’t want to waste prime search engine results page space promoting an item that, while containing the right terms, no one wants to buy. It’s not efficient, from a financial perspective.

That’s exactly why A9 considers a whole host of other ranking factors.

And one of the biggest factors is undoubtedly sales performance history. 

Sales Performance History

The clear starting point for A9 to consider after keywords is sales performance. If Amazon wants to promote products that are statistically most likely to sell, it seems natural that A9 will have been developed to prioritise those products with the strongest sales performance. 

It is likely that A9 will place more importance on products with a high conversion rate and high sales than with high conversion rates and low sales. This can make it tricky to get a new listing into a prominent position organically, but Amazon does offer several campaign types that can help.

There are also other ways to help improve the sales velocity of your products. One of the best ways is to fully optimise your listings. This can be done by:

Product Titles

Sales are the ultimate goal. But the next best thing is awareness. If a user doesn’t convert now, awareness of a product may make it easier for them to take action in the future. This makes your product titles hugely important. 

As mentioned earlier, there are millions of products available on Amazon. And while not all of them will show up for a given search query, most searches still have an overwhelming number of results. Your title is key to standing out. If a user is scrolling through the list, your product title is one of the things that’s going to make them click… or not. 

Product Description

There are lots of things that impact customer behaviour, and which can either encourage them to act or make them question their decision. One of the biggest factors is how much information is provided about the product. 

Imagine you’re selling a reusable water bottle, for example. An important feature for a customer may be that it’s dishwasher safe. Or a certain size. If your product description is too vague and doesn’t answer customer questions, it won’t sell. Use your product description as a chance to support your buyer’s journey. 

Product Features (Bullet Points)

Carrying on from what we said above about the importance of a good, thorough product description, it’s also important to remember that every shopper’s time is precious. While some will be willing to sit and read through a description with a nice cup of tea, others simply want quick facts. That’s where Amazon’s product features capabilities can come in handy. The product features element of a listing allows you to cherry-pick a few important aspects of your product, and highlight them using quick, easily scannable bullet points. It can be great for boosting sales. 

Product Images

Product images, product features, and product descriptions all go hand in hand. While descriptions and features are designed to help create a fuller story, product images are designed to help potential buyers get more of a feel for what you’re offering. 

To increase sales, and therefore influence the A9 algorithm with a strong sales history and performance, it’s often recommended to include a variety of images which show your product from different angles. You should also use images to highlight or clarify specific aspects of the item. Be sure to check Amazon’s image requirements. 

Other Amazon Ranking Factors

So far, we’ve looked at keywords and sales performance history as major factors that the A9 algorithm looks for, and major factors influencing position in the SERPs. But there are several other elements that are very likely to play a role, too. Of them, there are four specific factors that we think every Amazon seller should know:

1. Backend Keywords

When we walk about ‘keywords’, we’re usually referring to frontend keywords. These are the keywords that you incorporate into your customer-facing content, such as your product titles. 

But there’s another form of keyword, too: backend keywords. 

Backend search terms can’t be seen by your customers, but they can be seen by Amazon’s A9 search algorithm. They can help you to better inform A9 about what your product is, and who it’s for, without needing to publish that information. 

For example, you may be keen, for consistency, to refer to your product by one specific name, e.g., ‘shower gel’, but you could add ‘shower scrub’ as a backend keyword for ranking purposes. 

2. Price

Optimising a product listing, as we’ve looked at above, is about getting people excited and prepared to buy your product. All, of course, with the end goal of improving sales figures and, subsequently, improving rank. 

But there’s one final hurdle that many Amazon sellers overlook: price. Even with the best titles, best descriptions, and best images, you can still fall at the final hurdle if your pricing isn’t competitive. So, pricing matters. And the A9 algorithm knows it. It knows that products priced beyond budgets – or products priced so low that questions are raised about quality – are deterrents. And it will lose you some big A9 marks. 

3. Product Availability

Like price, product availability is another ‘final hurdle’ sort of factor. Again, a customer may be excited and ready to buy thanks to your optimisation. They may also be impressed with your product’s price point. But when it actually comes down to it, if you don’t have any stock, there’s really nothing that the customer can do.

That’s why good inventory management is so critical when it comes to sales, and when it comes to the A9 algorithm. 

Amazon FBA (Fulfilled by Amazon) can be a useful service here, as it delegates order management to Amazon itself. They’ll contact you when inventory hits a low threshold, so you can send more stock. 

4. Customer Reviews

Amazon reviews are a key park of Amazon’s algorithm that will determine how high your organic rank will be. It’s important to have a high percentage of positive customer reviews for your product. It’s also important to have honest reviews and to respond to negative reviews.

We could have discussed customer reviews as part of listing optimisation because a finely tuned review profile can have a big impact on sales. Instead, we think it’s important to consider product reviews from a brand engagement standpoint. 

Brand engagement – interactions between a brand and customer beyond a mere transaction – is important to the A9 algorithm. It shows the technology that this isn’t just a brand that sells things, but a brand that has a deeper relationship with its customers. That’s something that Amazon values. Any sort of relationship markers that Amazon A9 can track, analyse, and utilise, it will. 

Final Thoughts

Throughout this guide, we’ve covered a great deal. We’ve looked at what Amazon A9 is, how it works, what it does, and how sellers can influence it and get the most value from the technology. But that’s far from the end of the story. 

The truth is that the A9 algorithm is constantly changing. Just like Google’s algorithm, it’s always being updated and tweaked to ensure users are getting the most relevant results, every time. 

That’s why Amazon Search Engine Optimisation can never be a one-time thing; that’s why we’re always here with new guides, supporting you on your journey to Amazon success. 

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