Amazon A9 Algorithm: How Amazon Search Works in 2024

As an Amazon seller in 2024, you know just how fierce the competition is on the world's largest e-commerce platform. 

But have you ever wondered how Amazon decides which products to show when a person searches for a keyword? Enter the Amazon A9 algorithm — the search engine system behind Amazon's search results.

In this article, we'll cover the basics of the A9 algorithm and explain how it works. We'll also cover some of the top A9 ranking factors and how to optimize each factor to boost product rankings and sales.

What is the Amazon A9 algorithm?

The Amazon A9 algorithm is a complex system that powers Amazon’s product rankings and determines which products appear in Amazon's SERPs (search engine results pages).

The A9 algorithm considers keyword relevance, sales performance, and conversion rates to decide where products should appear in Amazon search results.

Optimizing for the algorithm—SEO (search engine optimization)—is a key technique sellers focus on to boost organic visibility and sales.

How the Amazon A9 algorithm works

The A9 algorithm was developed by Amazon's subsidiary A9.com, which began developing search engine and advertising technology in 2003.

Initially, the algorithm heavily relied on keyword relevance and still does, but over time, refinements were made, placing more weight on customer behavior and incorporating more advanced machine learning techniques more recently.

Over time, the algorithm has become more holistic, considering a wider range of factors to provide customers with the best search experience possible.

The Amazon A9 algorithm uses a two-step process to match and rank product results — relevance and performance.

Step 1: Relevance

The A9 algorithm first matches products to search queries based on keyword relevance.

The algorithm analyzes the keywords in a product listing (title, bullet points, description, and backend keywords) for relevance. It matches these keywords with a customer's search query to determine the most relevant product.

For example, when one searches for "leather writing journal," the top results include close variations of that keyword in the product titles (for example, "leather journal writing notebook" or "leather bound journal").

Naturally, including relevant keywords isn’t the sole factor the algorithm considers when determining a product’s position in search results, but it’s a crucial first step.

Step 2: Performance

The next step is for the algorithm to rank matched products using machine learning models that look at performance factors like sales performance (total sales volume, recent sales volume), conversion rates, and reviews.

Products that sell well and that customers love will naturally rank higher, as Amazon’s goal is to maximize sales and provide customers with the best products at the best price.

A9’s algorithm also considers factors like product availability and fulfillment methods (with preference given to Prime-eligible items).

Continuous learning and adaptation

The A9 algorithm uses adaptive learning models that combine user preferences with actual search data to continuously optimize product rankings.

The aim of these models is to accurately determine user intent with context and refine each search result to fulfill the buyer intent for each unique search query.

The A9 algorithm constantly learns and evolves to improve and provide more accurate customer search results. This means that optimizing for the algorithm isn't a "set it and forget it" task for sellers.

Maintaining top-ranking positions requires ongoing optimization efforts, including keeping listings up-to-date, maintaining competitive pricing and stock levels, and ensuring strong sales performance.

Top Amazon A9 algorithm ranking factors 

1. Keyword relevance

Keyword relevance is a crucial factor in the A9 algorithm that drives traffic and sales, directly impacting how a product matches a search query.

A product listing that uses relevant keywords in the title, description, bullet points, and backend will show higher search results than a product that does not, assuming all other things are equal.

How to optimize:

• Conduct detailed keyword research using Amazon seller tools to identify relevant keywords with sufficient search volume.
• Include keywords in your product title, bullet points, description, and backend.
• Avoid "keyword stuffing"; focus on natural language use and incorporate keywords where appropriate.
• Analyze top-performing products for your target keywords to identify what the algorithm is rewarding.
• Use long-tail keywords to target specific customer searches that might be less competitive.
• Assess the keywords in listings based on search trends and adjust as needed.
• Evaluate keyword performance and update as necessary.

2. Conversion rate

Conversion rate is important in the A9 algorithm because it reflects a product's performance and relevance to search queries.

A product with a high conversion rate signals to Amazon that it is a good match for specific search queries. 

This creates a positive feedback loop where rankings improve as conversion rates increase, driving more sales.

How to optimize:

• Track your "Unit Session Percentage" in Amazon Business Reports (measures the probability of a user buying after viewing a product).
• Write compelling copy for product listings to build trust and convert.
• Add engaging, high-quality images to your product listings.
• Ensure that your pricing structure is competitive.
• Offer promotions and deals to incentivize purchases.
• Use A+ content (if available) to provide more detailed product information.
• Prioritize responding promptly to any customer questions and address potential concerns.
• Consider using Amazon PPC (pay-per-click) advertising to drive relevant traffic and increase conversion rates.

3. Product reviews and ratings

Product reviews and ratings are essential for the A9 algorithm because they influence customer trust and purchase decisions.

A product with a high average rating and many reviews (e.g., 4.8/5 stars from 500+ reviews) signals that it is high-quality and satisfies buyer intent.

Reviews also include additional content that provides context about a product in relation to search queries.

How to optimize:

• Directly request happy customers to leave reviews through follow-up emails.
• Use Amazon's "Request a Review" button whenever possible to maximize the number of reviews.
• Respond promptly to all negative reviews in a professional manner.
• To prevent negative reviews, clearly address common concerns in the product listing.
• Aim to maintain an overall rating of at least 4.5 stars or above.
• Consider using Amazon's Early Reviewer Program to gather initial reviews.
• Consider using paid ads to get initial sales and reviews.

4. Click-through rate (CTR)

The A9 algorithm values click-through rate (CTR) because it reflects a product's relevance and customer appeal.

If a high percentage of people click on a product listing after searching for a query, the algorithm understands it made a "good" decision in showing that product and will push it higher because of its relevance.

How to optimize:

• Create compelling, keyword-rich titles that accurately describe your product and compel clicks.
• Use high-quality images for products that stand out in search results.
• Optimize your product listing preview to include price and desired features.
• Use every image slot available to showcase your product from multiple angles.
• Consider A/B testing various titles and images to find which combination of copy and images has the highest CTR.
• Maintain a 4.5+ average review rating and gather multiple reviews to build trust.
• Maintain competitive pricing to drive clicks.

5. Sales performance

Sales performance matters greatly for Amazon's algorithm because it shows a popular product and happy customers.

A strong and consistent sales history, and ideally, an upward sales velocity, signals to Amazon that a product is in high demand and meets customer expectations. More sales equals better rankings.

How to optimize:

• Focus on various strategies to increase sales volume, such as creating special promotions.
• Maintain a consistent inventory to avoid stockouts, which can cause inconsistent sales.
• Optimize product listing copy to increase click-through and conversion rates.
• Use Amazon advertising to quickly boost initial sales and visibility.
• Request reviews and aim for a high average review rating.
• Consider bundling products and/or offering variations of products to appeal to a wider audience.
• Analyze sales data regularly to find trends and opportunities to increase sales.

6. Product listing quality

The A9 algorithm rewards high-quality product listings, which attract more clicks, engagement, and sales.

A "quality" listing can be defined as one that accurately describes a product, uses compelling and engaging images, has detailed information, and has clear pricing.

Don't allow poor listing quality to ruin the sales of a great product.

How to optimize:

• Create high-quality product descriptions that accurately describe a product.
• Ensure that your product listing is accurately categorized.
• Utilize A+ content when possible to provide detailed information.
• Keep listings up-to-date with the latest product information (algorithms love updated content).
• Use bullet points in the product description to improve user experience and highlight key features and benefits.
• Include relevant product specifications and dimensions.
• Incorporate call-to-actions in the product description.
• Look at multiple top-ranking products and identify commonalities to understand what's working. Then, apply that knowledge to your listing.

7. Seller performance

Seller performance, not to be mistaken for sales performance, is your general status as an Amazon seller.

When ranking products, the algorithm considers metrics like order defect rate, shipping times, and customer responsiveness.

A9 seeks to promote Amazon sellers with a strong and reliable track record of fulfillment, prompt shipping, and customer service.

How to optimize:

• Maintain a high "seller rating" by providing prompt, polite, and helpful customer service.
• Minimize order defects by partnering with good suppliers.
• Minimize late shipments and cancellations by ensuring inventory is well-stocked to avoid stockouts.
• Ensure your logistics/shipments are organized to avoid late shipments and order cancellations.
• Consider using Fulfillment by Amazon (FBA) to provide the fastest shipping speed and reliability.
• Regularly monitor your seller metrics in Amazon Seller Central to see what needs improvement.

FAQs

​​How often does Amazon update its A9 algorithm?

Amazon's A9 algorithm is constantly learning, changing, and improving. Amazon does not frequently publicly disclose changes, and there is no set schedule for updates. 

However, what is clear is that the algorithm is continuously improving search relevance and user experience.

Rankings are updated hourly, but new rankings can take several days to appear in search results.

Does the Amazon “A10” algorithm exist?

No, there is no such thing as the Amazon "A10" algorithm. Amazon has not officially used this term, and there is no reason to believe an entirely new algorithm exists.

Amazon's A9 algorithm has seen significant changes, especially post-2020, that appear to prioritize listing performance and relevance over keyword stuffing.

These changes are what some claim to be A10, but these changes simply reflect an updated A9 algorithm.

How does Amazon’s A9 algorithm compare to Google’s search algorithm?

Both Google's search and Amazon's A9 algorithms use keywords to determine relevance.

The key difference is that Google's algorithm also focuses on fulfilling search intent for non-product-related queries, while Amazon focuses specifically on fulfilling buyer intent to drive sales.

Google's algorithm is also significantly more complex, with over 200 ranking factors presumed to exist based on experiments, Google patents, and more.

Are there any tools or services that can help with A9 optimization?

Amazon seller tools allow you to research keywords, find search volume, analyze competitors, and utilize various other features that help with listing optimization.

Some of the most popular options include Jungle Scout, Helium 10, and AMZScout.

Additionally, agencies offering Amazon SEO services will have specialists who know how to best utilize these tools and can help optimize your product listings to improve rankings and drive sales.

The bottom line

The Amazon A9 algorithm boils down to keyword relevance plus performance. Find the right keywords, create optimized listings, sell high-quality products, and provide excellent customer service.

Do that, and you’ll do just fine. You don’t need to become a machine learning expert to rank higher and sell more products.

Remember, A9 isn't just looking for keywords; it's hunting for products that match shoppers' wants. So, focus on crafting listings that speak to your customers, not just the algorithm.

At the end of the day, the fundamentals of Amazon’s algorithm won’t change anytime soon, so focus on the basics, and you’ll see results.