Clarification on Conversion Deduplication When Using GTM and Google Ads API (uploadClickConversions)

[Linh Luong Thi]

Hello Google Ads Support,

We are currently tracking conversions using:

• Google Tag Manager (GTM) with the “Google Ads Conversion Tracking” tag on the client-side

• Google Ads API (uploadClickConversions) from our backend server

We would like to ensure that when both methods are used, conversions are not counted twice.

Questions:
1. If we fire a GTM conversion tag with a transaction_id, and also send the same conversion via uploadClickConversions with the same orderId, will Google automatically deduplicate and count only one conversion?
2. In case transaction_id / orderId is not present, does Google fallback to deduplication based on gclid, conversion_action, and conversion_time?
3. Are there any required conditions or best practices to ensure deduplication works reliably when using GTM and API together?

We want to be confident that using both methods won’t result in duplicated conversions being reported.

Thank you for your support.

[Google Ads API Forum Advisor]

Hi,

Thank you for reaching out to the Google Ads API support team.

I understand that you are tracking conversions using GTM with the “Google Ads Conversion Tracking” tag on the client-side and Google Ads API (uploadClickConversions) in the backend. Please find the answers for your questions below:

1. If we fire a GTM conversion tag with a transaction_id, and also send the same conversion via uploadClickConversions with the same orderId, will Google automatically deduplicate and count only one conversion?

• Kindly note that, as per this article both the transaction Id and order id are same. The term "order ID" is used instead of transaction ID in the context of offline conversions, including offline conversion adjustments and enhanced conversions for leads. So, If you upload same conversion twice, Google ads recognizes and omits the duplicate if two conversions share the same ID. Based on the question asked, it seems like you are thinking that two conversions are uploaded when a transaction Id is fired and when you upload the conversions using Google Ads API. Kindly note that all this comes under the same process and the conversion is being uploaded only once.

2. In case transaction_id / orderId is not present, does Google fallback to deduplication based on gclid, conversion_action, and conversion_time?

• Yes, If a transaction_id or order Id is not present or is empty, Google Ads will indeed attempt to deduplicate conversions based on a combination of gclid, conversion_action and conversion_time. You can find the information about this in this FAQ.

3. Are there any required conditions or best practices to ensure deduplication works reliably when using GTM and API together?

• For the most accurate and reliable conversion tracking, you should always prioritize and consistently implement unique transaction_id/orderId values for every conversion. This ensures that real unique conversions are counted once, and other conversions with same ID's are ignored.

Thanks,
 

Google Ads API Team

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[2025-06-23 12:09:18Z GMT] This message is in relation to case "ref:!00D1U01174p.!500Ht01rfwVP:ref" (ADR-00315314)