Top-of-Search Optimizer (TOSO)

Understanding the importance of Top-of-Search on Amazon and how to use Perpetua's TOS Optimizer with your keyword boosts

Andrea Mamone avatar
Written by Andrea Mamone
Updated over a week ago

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What is Top-of-Search?

Top-of-Search, or simply TOS, is the placement where your ads (Sponsored products) appear on the search results page on Amazon. TOS refers to the first row on the first page of search results, and you will be able to spot these placements by seeing the “Sponsored” tag appearing just below the product image.

Why is Top-of-Search Important?

When your ads gain the Top-of-Search placement of the search results page on Amazon, you maximise the visibility of your ads and increase the chance of converting.

The Top-of-Search results on Amazon are considered important for several reasons:

  1. Visibility: The top search results receive the highest visibility and exposure to potential customers. Being at the top increases the chances of your product being seen and clicked on by users, which can lead to higher sales.

  2. Credibility and Trust: Shoppers often associate top search results with popular and reliable products, which can give a sense of credibility and trust to potential customers. They may perceive your product as being of high quality and popular among other buyers, increasing the likelihood of them making a purchase.

  3. Increased Sales: Higher visibility and credibility translate into increased sales potential. When your product ranks at the top, it is more likely to attract organic traffic and conversions. More people seeing your product can result in more clicks, which can lead to more sales.

  4. Competitive Advantage: The Amazon marketplace is highly competitive, with numerous sellers offering similar products. Achieving a top ranking can give you a competitive edge over other sellers in your category. It allows you to stand out from the competition and capture a larger share of the market. Customers often compare products and make purchasing decisions based on the search results, so being at the top increases your chances of being chosen over competitors.

  5. Algorithmic Factors: Amazon's search algorithm considers various factors when determining search rankings, such as relevance, sales velocity, customer reviews, and conversion rates. Higher search rankings lead to more exposure and sales, which, in turn, can improve your product's overall performance in the algorithm. This creates a positive feedback loop, where higher rankings can lead to more sales, and more sales can lead to higher rankings.

What is Top-of-Search Optimizer and When to Use it?

The Top-of-Search Optimizer (TOSO), refers to the practice of optimizing your advertising campaigns to appear prominently at the top of search engine results pages (SERPs).

With Perpetua, TOSO is the KPI Prioritization that can be enabled via launching a Keyword Boost (KB) if you are a Pro or Enterprise user (find out more about our subscription here).

In Perpetua, keyword boosts are a feature used to prioritize and bring more attention to selected keywords in your Sponsored Product goals by launching them in a separate campaign with a dedicated target ACoS and budget. Please find out more about Keyword boosts from this other very helpful article.

🚨Please note: TOSO can only be applied to Keyword Boosts with a single EXACT match keyword in it. The option to add more keywords will be greyed out.

By selecting TOSO as the KPI within your Keyword Boost, you prioritize the optimization towards Top-of-Search placement, rather than Target ACOS. Perpetua will then launch a separate campaign that will isolate that single keyword (used to launch the KB), to reach Top-of-Search (TOS) placements, by using Stream data to track and predict the best CPC for TOS (as well as ROS). This means that bids will change to maintain TOS with the lowest bid possible. Bids are updated twice a day. TOS bids are applied using a TOS multiplier.

🚨If you are not already subscribed to Stream, you will be the day after activating Top-of-Search Optimizer. The Optimization will start then. If otherwise, please reach out to our team.

Find out more about Stream from our Perpetua Ad school lessons here. 🎓

You can view the TOS multiplier and the bids by navigating through the Keyword Boost campaign > Targets Tab:

As explained above, the ToS Engine works by overriding keyword bids and the Top-of-search multiplier. The keyword bid override will show up in the activity stream as “Target Updated” by with the bid value rounded to 0 decimal places as shown in the screenshot below:

How to Enable Top-of-Search Optimization?

Enabling this feature is only a few steps away:

  1. When setting up your Keyword Boost (How to here), assigned a name to the campaign:

  2. Go to the “KPI Prioritization” section and select the “Top of Search” option:

  3. When TOSO will be selected, enter the Daily Budget value:

    🚨You may expect your budget to run out quickly since the day of launching your KWB with Top-of-Search Optimizer enabled, as the bids might be high in order to reach top of search. However, you will never spend more than the assigned daily budget.
    The Optimizer will perform bid shading in order to reach and maintain top of search for the lowest cost possible over time.

    🚨Please note that “Going Dark Mitigation” does not apply to Top-of-Search Optimizer. Going dark is a phenomenon that happens in the other KPI Prioritization (Target Acos). When the budget is very tight on the campaign, going dark scales back engine target ACOS and the bid is reduced for all keywords throughout the day in order to conserve the budget to last for the whole day. When TOSO will be selected for your KWB, the engine will not apply the above, meaning that the bids will not vary in order to save on budget.

  4. Click on the purple “Boost Keywords” button to launch the campaign. It will be listed in the “Campaigns” tab inside the goal, and in the “Keyword Boosts” from your “Experiments” tab.

Best Practices

  • Use Exact Match Keyword: Using an EXACT match is the cleanest way we could optimize for the top of search. Using PHRASE and BROAD match types could lead to some wasted spend due to the larger bracket of search terms that it would cover.

  • Name your campaign based on the name of the actual keyword you are optimizing. This will highlight the campaign among the campaigns’ list within the goal it was launched from.

  • Use TOSO if your strategy aims to increase your conversion rate (CVR). TOSO will increase your bids in order to reach the Top-of-Search placement, by leveraging Stream data. This could lead your brand to gain a better organic rank and Share of Voice (SOV) over time.


  • When you have multiple ASINs in the goal where you launched the KWB with the TOS optimizer, do we aim for full TOS coverage?
    For a given campaign, only a single ASIN gets selected to be shown if the keyword wins the bid. Hence for a selected campaign, we only target one slot which we are able to get with the minimum CPC.

  • How do we know that we reached TOS through the Stream data?
    We get hourly placement data using stream. If in a given hour we see a record of the ad within the TOS Optimized campaign appearing in Top-of-Search for that keyword, we consider that hour. Out of the 24 hours in a day, for how many hours did we see ToS Placement for the ToS optimized campaign is what the daily ToS percentage metric shows.

Article last updated June 2023. If you find this information to be out of date, please contact

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