Google Ads Developer Blog

The “What” and “Why” on Meridian: Ads DevCast E6

Thursday, May 28, 2026

Measuring the true impact of your marketing spend is complex, especially when you look across channels and mediums. In Episode 6 of Google’s Ads DevCast, "The 'What' and 'Why' on Meridian," we sit down with Product Manager Katie Munro and Developer Relations Engineer Jeff Li to explore Meridian, Google's open-source Marketing Mix Modeling (MMM) framework, and how it helps advertisers make data-backed strategic budget decisions. Watch the full episode Hear the full episode Here is a summary of the talking points from our discussion on what Meridian is, how the math works, and the newly announced surfaces to help you implement it. What is Meridian? Meridian is Google's open-source Marketing Mix Modeling (MMM) framework. It provides a holistic, privacy-safe view of marketing ROI by analyzing aggregated historical data across all channels (digital, TV, print) alongside non-advertising factors (seasonality, economic conditions). It helps you determine the incremental lift of your marketing (sales caused by ads) versus baseline sales (sales that would have happened anyway). The Core Math: Hill Curves & Adstock Meridian uses statistical models to capture the real-world behavior of advertising:

Hill Curves: Models diminishing returns, showing where you have room to increase spend (headroom) and where you have saturated a channel.

Adstock: Models the lagged effect and decay of advertising over time, capturing the delay between seeing an ad and making a purchase.

The Measurement Trifecta Meridian completes the modern measurement framework:

Attribution (GA4): For day-to-day tactical campaign tweaks.

Incrementality Experiments (Meridian GeoX): To test specific hypotheses in the real world.

MMM (Meridian): For macro-level, strategic budget planning.

New Meridian Releases from GML 2026 We discuss three major additions designed to make MMM more accessible and accurate:

Meridian in GA360: A turnkey, integrated MMM solution within Google Analytics 360 that uses existing behavioral data to provide cross-channel ROI insights without requiring a data science background.

Meridian Studio: A Google Cloud-based enterprise platform to build and scale models, featuring native agentic AI to automate data quality checks, suggest model health improvements, and assist in scenario planning.

Meridian GeoX: An open-source geo-based incrementality solution that acts as a calibration engine, allowing you to run geographic experiments and feed "ground truth" causation data back into your Meridian model.

Next Steps:

Watch the full episode on YouTube (or listen to it)

Try Meridian: https://goo.gle/try-meridian

Try Meridian Studio: https://goo.gle/try-meridian-studio

Try Meridian GeoX: https://goo.gle/try-meridian-geox

Check out the Meridian Developers website to read the documentation.

Join our developer community on Discord to ask questions and discuss.

Cory Liseno

Google’s Advertising and Measurement Developer Relations team

Display & Video 360 API will start supporting Demand Gen resources on June 10, 2026

Wednesday, May 27, 2026

Today we’re announcing the upcoming rollout of Demand Gen resource support to all Display & Video 360 API users starting on June 10, 2026. This feature will be rolled out to Display & Video 360 partners over two weeks. By June 24, the feature will be available to all partners. Ahead of June 10, verify that your API integration can handle the additional Demand Gen line items and ad groups that will be included in list responses once the feature is rolled out to your partner. What’s changing? Originally launched in closed beta on April 14, 2026, Demand Gen resource support includes management and retrieval capabilities for Demand Gen resources and their targeting. Demand Gen resources include the following:

LineItem resources with a lineItemType field value of LINE_ITEM_TYPE_DEMAND_GEN.

AdGroup resources with an adGroupFormat field value of AD_GROUP_FORMAT_DEMAND_GEN.

AdGroupAd resources using any of the following fields: demandGenVideoAd, demandGenImageAd, demandGenCarouselAd, demandGenProductAd. Demand Gen AdGroupAd resources are retrievable using Display & Video 360 API currently, but these fields will not be included in the retrieved object until full support is rolled out to your partner.

After these features are rolled out to your partner, the API will support get, create, delete, and patch requests for these resources. In addition, these resources will be included in advertisers.lineItems.list and advertisers.adGroups.list responses, alongside the line items and ad groups that are already supported. What actions do I need to take? If you are currently retrieving LineItem and AdGroup resources using advertisers.lineItems.list and advertisers.adGroups.list, update your integration by June 10, 2026 to support the Demand Gen resources that will be included in responses once the features are rolled out to your partner. The other features included in this rollout add support for Demand Gen resources that are explicitly identified when using new or existing methods. These changes only impact requests that would have previously returned an error, so no changes should be needed beforehand to ensure the stability of your integration. Once the features are rolled out to all partners after June 24, 2026, you can start explicitly retrieving, creating, and updating Demand Gen resources. See our existing guide for step-by-step instructions on how to begin serving Demand Gen ads using the Display & Video 360 API. We will make another announcement once this rollout begins. If you have any questions or want to discuss this post, please reach out to us on our “Google Advertising and Measurement Community” Discord server.

- Trevor Mulchay, Display & Video 360 API Team

Standardizing Reach Metrics with Total Co-view in the Google Ads API

Wednesday, May 27, 2026

Starting on June 2nd, 2026, the Google Ads API will transition reach metrics to a "Total Co-view" definition. This update aligns Google Ads reporting with offline media and third-party measurement standards, ensuring consistency across all reporting surfaces, including the Google Ads UI and Editor. The updated definition of the video view metrics will include all individuals who viewed the ad on connected TV devices, including cases where multiple people are watching YouTube together on the same TV screen. This change impacts the following reach metrics at the campaign level:

metrics.unique_users

metrics.average_impression_frequency_per_user

metrics.unique_users_two_plus

metrics.unique_users_three_plus

metrics.unique_users_four_plus

metrics.unique_users_five_plus

metrics.unique_users_ten_plus

Required actions No API version migration or code changes are required to see this new behavior, as it is a data definition change that will be applied automatically. However, developers and advertisers should be prepared for a potential change in reported reach and frequency values for dates beginning with the launch date. We recommend updating internal documentation or dashboards to reflect this shift in measurement methodology. If you have any questions or concerns regarding this update, please reach out via the “Google Advertising and Measurement Community” Discord server.

Mattia Tommasone

Google’s Advertising and Measurement Developer Relations team

Ads DevCast: Google Marketing Live 2026 bonus episode

Thursday, May 21, 2026

We're excited to bring you a special bonus episode of Google’s Ads DevCast! We’re going over a few of the bigger announcements and updates from Google Marketing Live (GML) 2026 that directly affect our developers and technical users, across Tagging, Data Manager, and Meridian. Watch it at goo.gle/watchadsdevcast Hear it at goo.gle/listenadsdevcast Key Highlights from the Episode

Tagging improvements: Discover the new Google tag gateway In-UI setup offerings (featuring GCP, Akamai, Cloudflare, and Fastly) and new CMS integrations. We also discuss Visual Tagging for troubleshooting purchase conversions, and how we are bringing GTM capabilities directly to the Google tag.

Data Manager API: Learn about the value of single ingestion and multi-feed, allowing you to flow first-party data to multiple Google products with a unified schema. We also touch on Confidential Matching for privacy-safe audience building.

Meridian (open-source MMM): Get an overview of the new Meridian offerings announced at GML, including Meridian in GA360, Meridian Studio (featuring native agentic capabilities), and Meridian GeoX for incrementality calibration.

Listen to the episode to get all the details and prepare for next week's deep dive into Meridian! Don't forget to take our Episode Survey to let us know what you think! If you have any questions or want to discuss this post, please reach out to us on our “Google Advertising and Measurement Community” Discord server.

Cory Liseno

Google’s Advertising and Measurement Developer Relations team

Changes to Offline Click Conversion Import Support in the Google Ads API

Friday, May 15, 2026

Starting on June 15, 2026, the Google Ads API will no longer accept new adopters of offline conversion imports, including enhanced conversions for leads. As with our previous announcements for session attributes and IP address, and Customer Match, Data Manager API is now the primary API for importing offline conversions. Developers who have not adopted offline conversion imports or Enhanced conversion for leads, or have not imported offline conversions between December 2025 and May 2026, will receive an error if they attempt to import offline conversions. Developers who have already adopted offline conversions or Enhanced conversions for leads can continue importing using the Google Ads API while they integrate with the Data Manager API. See our migration guide for Google Ads API users to start integrating with the Data Manager API. Technical details

Developers will be allowlisted by their developer token.

Once this change is rolled out, new adopters will receive the error CUSTOMER_NOT_ALLOWLISTED_FOR_THIS_FEATURE when attempting to use the ConversionUploadService.UploadClickConversions method.

See the documentation for integrating with the Data Manager API for offline conversion imports for Google Ads API users.

Reach out to the Google Ads API support or Data Manager API support channels if you have any questions. If you have any questions or want to discuss this post, please reach out to us on our “Google Advertising and Measurement Community” Discord server.

- Ben Karl, on behalf of the Google Ads API Team

Announcing expanded experiment functionality in Google Ads API v24.1

Thursday, May 14, 2026

We are excited to announce a significant expansion of the Google Ads A/B experiments feature set in the v24.1 release, launched yesterday, May 13, 2026. We know API functionality is critical for advertisers who manage large sophisticated accounts, and we want to give these advertisers the capability to better create and manage their A/B experiments at scale. This update broadens the platform's current scope, enabling advertisers to leverage the power of experiments for a broader range of testing scenarios to drive campaign performance. Direct experiment reporting One of the most requested enhancements is the ability to query experiment statistics directly through the API. Previously, you had to manually calculate statistics by querying campaign resources. With v24.1, we are exposing experiment arm-level and significance stats, including:

Control arm stats: The average value of metrics in the control arm.

Point estimates: The mean value of the difference between the control and treatment arms, calculated via the jackknife method.

Margin of error: The radius of the confidence interval.

P-values: Represents the calculated probability that the difference could have occurred by chance.

New experiment types We are expanding support for a variety of experiment types to help you find the best configurations for your business:

Feature-specific tests (AI Max and broad match): Test the impact of enabling AI Max or broad match keywords. These use an intra-campaign workflow, where the feature is tested within the original campaign shared by both the control and treatment arms.

Custom video experiments: Run custom experiments consisting of Video campaigns.

Performance Max replacement: Test how your Shopping campaigns perform compared to Performance Max.

Performance Max asset optimization: Specifically for Performance Max, you can test different variations of assets including text, images, and videos. This asset optimization workflow helps determine which creative combinations drive the best results.

While these updates cover a significant number of use cases, we are continuing to work on the platform and plan to introduce even more experiment types in future releases. Where can I learn more? Updated documentation and code examples are available on the Google Ads API Developer site. We also encourage you to join the discussion and share your feedback on our Ads and Measurement Community Discord server.

- Laura Chevalier, Google Ads API Team

Announcing v24.1 of the Google Ads API

Wednesday, May 13, 2026

Today, we’re announcing the v24.1 release of the Google Ads API. To use the new v24.1 features, you must upgrade your client libraries and client code. All the updated client libraries and code examples have been published. Come join us for a live walkthrough of this release in our "Google Ads API Release Highlights" event on Discord, our Ads Developers YouTube Live, or our LinkedIn Live event tomorrow (May 14 at 10a ET). This will also be recorded and posted on YouTube for those who can’t make the live events. If you have any questions or want to discuss this post, reach out to us in the #ads-api channel on Discord. New Features Mobile Device Platform Segment: Understanding where your traffic comes from is critical for campaign optimization. With v24.1, you can now segment campaign-level and customer-level reports using the segments.mobile_device_platform column. This field utilizes the new MobileDevicePlatform enum (supporting values like IOS and ANDROID), allowing you to cleanly isolate performance data and adjust bid strategies based on the user's mobile operating system. Classic images in DemandGen campaigns: As of v24.1, you can use the classic_display_images field of DemandGenMultiAssetAd to upload static image ads to serve on the Google Display Network (GDN) within your Demand Gen campaigns. These images are served as-is, without being combined with additional assets. This format provides full control over your creative branding. Refer to our help center for more information. Support for passkeys: Passkeys provide a simple and secure alternative to passwords. Google now requires some advertisers to use a passkey to authorize sensitive actions within their Google Ads account. The v24.1 introduces a new passkey_enabled field that indicates whether the user has a passkey enabled. Revamped support for Experiments: Experiments let you test the impact of your proposed changes. If you split the budget or traffic between the original campaign and experiment, you can easily compare the results over a specified time period. If the experiments produce better results, you can apply the experiment to the original campaign or replace the original campaign. The v24.1 introduces support for new experiment types: AI Max experiments, Video experiments, Demand Gen experiments (this and video are the same API type) and Performance Max experiments. You can now retrieve and compare detailed performance metrics (such as clicks, conversions, and impressions) across individual experimental arms. This makes side-by-side performance analysis easier and more transparent. Refer to our guide to learn more about experiment workflows. New Data Retention Policy for Google Ads: We recently announced that starting June 1, 2026, Google Ads and related measurement APIs will transition to a 37-month data retention policy for granular performance statistics (daily, hourly, and weekly). The V24.1 introduces a new DateRangeError.REQUESTED_DATE_GRANULARITY_NOT_SUPPORTED error code to support this change. The following resources can help you get started: