August 24 2023

3 minutes of reading

Custom Bidding, tailor-made scoring


Aleksander Chim

In this article, you will learn about:

  • What Custom Bidding is and its potential applications.

  • What an example of a custom script can be like.

  • The limitations of Custom Bidding and when conventional strategies may be better.

  • Goal Builder as a simpler alternative.

What is Custom Bidding, and how can you apply it?

Display & Video 360 platform offers several options for buying advertising space that focus on:

  • Brand building (e.g. maximizing ad viewability).

  • Website traffic (e.g. maximizing clicks).

  • Conversions (e.g. maximizing the number of conversions).

Built-in solutions tailored to campaign goals can help clients build their business. However, what if we have additional insights from Google Analytics or other proprietary databases?

If that is the case, a custom script may turn out to be a better solution. It allows us to define key objectives based on Floodlight data, Google Analytics, and available targeting within DV360. Basic knowledge of the Python programming language will surely come in handy when you want to effectively create solutions within a custom script. With Python and predefined metrics, we can bring our insights to life.

Custom bidding jest narzędziem, które umożliwia nadawanie odpowiedniej wagi wybranemu zdarzeniu, związanego z emisją reklamy (gdzie się emitowała, jak długo, gdzie, itp.), lub ze stroną (wizyta, przeglądana kategoria, zakup). 

Example scenarios and solutions:

Example 1

The client aims to generate sales with a value over PLN 1000, as set as their ROAS target.


We collect sales information using the built-in method (total_conversion_value) and assign a point whenever this value exceeds PLN 1000.

Source: Custom Bidding section as part of DV360.

Example 2

Our insight indicates that smartphones are crucial touchpoints. Additionally, the client wants our ad to be visible on the page for at least 10 seconds.


We can use the built-in max aggregate function as the highest-weighted scenario. We assign 50 points for smartphone impressions lasting at least 10 seconds, while for other devices with sufficiently long ad views, we assign 10 points.

Source: Custom Bidding section as part of DV360.

If you want to explore all possible metrics and available features, I invite you to visit the DV360 documentation under “Custom Bidding Script Reference.”

Limitations and when conventional strategies may be better

Custom scripts can offer numerous benefits when based on insights or data. However, if we create complex rules without clear justifications, we run the risk of making errors and having poorer performance in basic campaign KPIs. Additionally, Custom Bidding is currently unavailable for audio ad inventory, YouTube, or guaranteed deals.

Another important consideration is the quantity of available signals. For a defined strategy to work, our rules must occur frequently enough for the system to identify the appropriate pattern. Otherwise, the campaign will not execute, or the results may be worse than expected.

Goal Builder: a simpler alternative to custom scripts

If you prefer not to write your own code, there is an alternative called goal builder, a built-in tool for creating custom algorithms.

Source: Custom Bidding section as part of DV360.

Thanks to Goal Builder, you can select floodlight or analytics conversions and assign weights to specific events. However, you only have control over the weights between events and not within them. For example, you can assign 1 point for website visits and 5 points for purchases, but you cannot score specific pages or product categories.

Additionally, you cannot rely on media campaign signals such as targeting strategies, devices, locations, etc.

If these limitations have not discouraged you, it is worth testing this solution as well.


Armed with the right knowledge and insights, you can use Custom Bidding as a tool to more effectively achieve your client’s KPIs by leveraging signals from various sources (DV360, Floodlight, GA). Avoid unnecessary complexity unless there are clear justifications. For example, if there is no solid reason to prioritize a specific day of the week, it is best not to do so as it may be counterproductive. However, in capable hands, a well-created custom script can elevate campaign optimization to a whole new level.

Do you have any questions?

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