Bol.com

How does the bol algorithm work and how do you become easier to find?

Lars Hurkmans·Co-founder·10 November 2023·Reading time 11 minutes

For every search, the bol algorithm shows the most relevant products and ranks them by popularity: the number of clicks and sales. You become easier to find by strengthening your category position and your keyword relevance, above all with a title that matches how consumers search. This is part 1 of our four-part series on findability on bol.

This is part 1 of a four-part series on the findability of your products on bol. We start with how the algorithm works, the foundation for the rest of the series. After that we cover tools such as bol Search Trends, Bollify and MarktMentor to improve your findability, followed by sponsored products to increase your visibility with paid placement. Finally we show you how to measure and adjust the effectiveness of these approaches. For the full overview of findability, see also findability on bol.

How do consumers find products on bol?

Consumers find products in two ways: through external traffic that is led to bol, and through the search and navigation options within bol itself. The bol algorithm is designed to show the most relevant products for every search. To understand that, we first look at how consumers navigate and find products on bol.

How does external traffic end up on bol?

External traffic reaches bol through Google Shopping and through content such as blogs, YouTube videos and social media. Bol actively uses Google Shopping to promote products that perform well on the platform. These products have proven to generate high conversions, which makes them attractive for external ads. Bol invests in these products because advertising on external platforms costs money, so the return on that investment matters.

Sellers have no direct influence on which products bol chooses to advertise on Google Shopping. The key to being included lies in strong product performance on bol itself, which results in high conversions.

Besides Google Shopping, consumers also find products through channels such as blog posts, YouTube videos and social media. Sellers can directly influence their findability outside bol by creating content themselves or by engaging parties that produce content, often on an affiliate basis. This is an important element in increasing the overall visibility and appeal of your products.

How does a consumer discover a product within bol?

Within bol, a consumer discovers a product through offer pages, the category tree or a direct search. Each method presents products in its own way:

• Offer pages: these pages show products that are promoted by bol, often based on popularity, seasonality or special campaigns.
• Category tree navigation: consumers who want to search more specifically can explore product groups through the category tree.
• Direct searches: the most direct method is using keywords. Products are then shown based on their relevance to the search terms entered.

Once a consumer is on a category or keyword page, they can filter the products further. With these filters, the consumer refines the search based on criteria such as brand, colour or price range.

How does the bol algorithm work?

The bol algorithm connects consumers to the products they are looking for by showing the most relevant products in a prominent place. It is designed to create both a smooth shopping experience for the customer and a successful sales platform for sellers. The goal is a balance in which the products most relevant to the customer's search appear prominently. That contributes to customer satisfaction and to sales opportunities for sellers.

What determines your category position?

Your category position is primarily determined by two factors: clicks and sales. The category rankings are the backbone of how products appear in the search results. Products that are clicked and sold more often get a higher position. For bol, that is an indication that a product is popular and relevant to consumers. Recent actions weigh more heavily than actions further back in time. Products can also climb faster through momentum, which means they have sold many units in a short period.

How do category position, buy box and conversions relate to each other?

Direct product attributes such as price, delivery promise, seller performance and conversions do not influence the category rankings directly. They have a more indirect influence by increasing a product's appeal to the consumer.

• Category position: a product's category position on bol is a direct reflection of its popularity, determined by the frequency of clicks and sales. A high category position means a product is viewed and bought more often, which indicates that it meets consumers' needs and preferences. This position is crucial, because it gives products better visibility and increases the chance of further sales.
• Buy box position: the buy box position refers to a product's place within the buy box on a product page, the area where customers actually make the purchase. Factors such as the product's price, the promised delivery time and the seller's historical performance play a direct role in this position. These elements influence the customer's buying decision. A competitive price, fast and reliable delivery and a strong seller reputation can improve the buy box position and increase the chances of a sale.
• Conversions: conversions may have no direct influence on the buy box or category position within bol, but they are very important for the promotion of products on external channels such as Google Shopping. Products that consistently show high conversion rates are seen by bol as more valuable for external promotion. That is because such products represent a greater chance of a sale, which justifies the investment in external advertising. A strategy focused on raising the conversion rate can therefore not only improve internal performance on bol, but also increase the visibility of products on external platforms.

How does bol determine your keyword position?

Your keyword position is determined by keyword relevance: how well a product matches a user's search. Bol determines that relevance through several levels of matching:

• Category matching: when a keyword directly matches one of the categories within bol, products in that specific category get increased relevance. The algorithm then recognises that these products are probably what the consumer is looking for. If a user searches for 'running shoes', for example, products in the category 'Sports & Leisure > Shoes > Running shoes' are automatically considered more relevant. This direct category matching is particularly effective, because it considerably increases the chance that a product appears high in the search results for that specific search.
• Specification matching: products with specifications that match search terms get a higher relevance score. Take the example of a search for 'blue running shorts'. Running shorts with 'blue' as the colour specification score higher in the search results, because colour is one of the attributes indexed by bol. That increases the chance that consumers find products that match their wishes exactly. While specifications such as brand, colour and material are often indexed, that is not true for all attributes, such as sustainability labels. This distinction matters for sellers, so they understand which attributes contribute to higher keyword matching and can therefore improve the findability of their products.
• Title matching: for keywords that do not directly match categories or specifications, the words in the product title are what mainly count. When searching for 'gift for Father's Day', a term that does not fall under a specific category or product specification, including 'Father's Day' in the product title largely determines findability. Products with titles that contain this search term, such as 'Father's Day Gift - Personalised Mug', score higher in the search results. For specific themes or occasions, such as Father's Day, the strategic use of relevant terms in product titles is therefore crucial for findability.

These levels of matching help bol show users the most relevant products for their specific search. A product's relevance combined with its popularity position ultimately determines how high a product appears in the search results.

How are category and keyword positions connected?

A product's position in category and keyword rankings is closely connected. A strong category position can lead to more visibility and therefore more clicks and sales, which in turn can improve a product's keyword position. That improved keyword position increases the product's visibility within specific searches, which strengthens the category position again. This cyclical effect makes a holistic approach to findability on bol essential. The position you see in the search results is not always purely organic, by the way; how to tell organic and combined positions apart is explained in rankings on bol: organic versus combined.

How does the algorithm respond in practice?

In practice, the algorithm runs through a fixed sequence for every search: first it looks for a category that matches the search term, then for specifications, and then for the product title. We make this concrete with the search 'marten repeller'.

How does bol match categories and titles?

Bol matches a search first against the categories and then against the product titles. Suppose a consumer searches for 'marten repeller'. The algorithm first searches the database to determine whether a category exists that matches this search term, such as the marten repellers category or related categories such as ultrasonic repellers. The products that fall into these categories and have 'marten repeller' in their title are shown first because of their high relevance score. This matches what we see in the image below.

Products that do not fall directly into the specific category but do have 'marten repeller' in the title are shown next. The popularity position of each product, determined by clicks and sales, then determines the order among these similarly relevant items. Within the group of products with similar relevance scores based on the match with the search, the popularity position is therefore decisive.

How do specific attributes refine the results?

As soon as a consumer makes the search more specific, for example 'marten repeller green', the algorithm refines the results on product specifications. It checks which products are labelled with the colour green as a product specification. These products are shown, as we see in the image below. Products that have 'green' both in their specifications and in their title get a higher relevance score, although it is not necessary to include the colour in the title. Here too, the popularity position determines the order among these specific green products.

How does bol adjust the filters to your search term?

Bol adjusts the available filter options based on the search term and the product category. The filters that appear, and their order, are meant to show the most relevant options for the consumer. For 'marten repeller green', filters appear that are relevant to the specific green marten repellers, such as how often other consumers have used those filters.

What happens with a search term that does not exist as a category or specification?

For a search term that does not exist within the category on bol, such as 'marten repeller gold', the algorithm applies an 'or' condition. That leads to a broader range of products that are either marten repellers or contain the colour gold in the title or specifications, which results in a diverse selection, as shown in the image below. This 'or' condition reveals an important aspect of keyword use and title optimisation on bol.

How do you build your product title strategically?

You build an effective product title by determining, for each keyword, whether bol recognises it as an attribute. Creating product titles on bol is guided not only by creativity, but also by a good understanding of the algorithm and of consumer search behaviour. A thorough analysis of how specific keywords are used within bol, and whether or not they are classified as product attributes, can significantly influence a product's visibility.

When a keyword denotes a specific attribute within bol's system, such as 'green' in the search 'marten repeller green', products with that attribute get priority in the search results. If a product does not have that attribute, adding such a specific keyword to the title is not always useful.

If a keyword is not directly linked to an attribute on bol, such as 'gold' in the search 'marten repeller gold', adding this keyword to the product title can actually set the product apart within a broader set of search results. That is especially beneficial when the algorithm combines different product attributes in an 'or' condition, which increases the chance of being discovered by consumers.

It is therefore important that sellers carefully weigh the interaction between keywords, product titles and bol's specifications. Strategically using relevant keywords in product titles, especially those that are not recognised as standard specifications, can increase findability and with it the chances of a sale. At the same time, avoid irrelevant specifications that can harm the user experience and conversion chances. Read more about building a strong, keyword-rich listing in optimising your listing on bol.

Which separator do you use in your product title?

Use the hyphen (-) if you want your product to be found for combinations of keywords. How you separate keywords in the product title determines how the algorithm interprets them and can influence a product's findability. There are two common ways to separate keywords: with the hyphen (-) or with the vertical bar (|).

• Using the vertical bar (|) in titles: the vertical bar is interpreted by the bol algorithm as an 'or' sign, which means it treats the keywords as separate entities. That can affect combination searches. In a title such as 'Marten Repeller | 2 Pieces', the algorithm sees 'Marten Repeller' and '2 Pieces' as separate elements. As a result, the product does not appear in the search results for the combination 'Marten Repeller 2 Pieces'.
• Using the hyphen (-) in titles: unlike the vertical bar, the horizontal separator provides better findability for combination searches. The hyphen is seen as a connection between the keywords, which makes the product findable for combinations of these terms. In a title such as 'Marten Repeller - 2 Pieces', 'Marten Repeller 2 Pieces' is treated as a combined search term, which increases the product's findability for this specific search.

It is therefore advisable to use the horizontal separator if you want your products to be found for combinations of keywords. That is especially important for products that are relevant to multiple search terms, where findability for specific keyword combinations can increase the chances of a sale.

What does the next part of this series cover?

The next part is about how you use keywords to increase your findability on bol. We now have a clear picture of how the bol algorithm works, with the role of category positions and keyword findability in the online sales landscape. These elements are the foundation for improving the visibility and appeal of your products on the platform.

In the next article we focus on how you use keywords to increase your findability on bol. We go deeper into strategies for effectively using both organic and sponsored keywords, with the aim of generating more clicks and sales. That helps not only with improving your position in categories and keyword results, but also with raising your overall sales performance.

To tackle this professionally and effectively, you use specialised keyword tools focused on bol. We look at tools such as bol Search Trends, Keyword Discovery by Bollify and the Keyword Guide by MarktMentor. These tools help you identify the most relevant and effective keywords for your products.

Follow us in the next part of this series, where we explain these strategies and guide you in using these tools to maximise your findability and sales potential on bol.

Summary: what to pay attention to

• Category position: determined by clicks and sales; recent actions weigh more heavily and momentum can make a product climb faster.
• Buy box position: determined by price, delivery time and seller performance, separate from the category position.
• Keyword relevance: built up through three levels, from category matching via specification matching to title matching.
• Popularity is decisive among products with a similar relevance score.
• Title: put a keyword in the title if bol does not already recognise it as an attribute, or to set your product apart within an 'or' condition.
• Separator: use the hyphen (-) for combination searches, not the vertical bar (|).