Reddit Ads API: Creating and Deleting Retargeting Audiences

What Is Retargeting in Reddit Ads?

On August 13, 2026, Reddit expanded its Ads API capabilities by adding support for creating and deleting Website Retargeting and Engagement Retargeting audiences. The update allows advertisers and developers to manage these audiences programmatically without having to use the Reddit Ads Manager interface.

The new functionality is particularly relevant to marketing agencies, large advertisers, and developers of automation platforms that manage multiple advertising accounts or regularly update their audience structures.

However, this does not mean that retargeting is new to Reddit. The update expands the capabilities of the Ads API rather than introducing a new targeting method.

How Retargeting Works in Reddit Ads

Retargeting allows advertisers to re-engage users who have already interacted with their brand, website, or advertisements. Reddit offers two primary types of retargeting audiences.

Website Retargeting

Website Retargeting audiences are built from events received from an advertiser's website through Reddit Pixel or the Conversions API (CAPI).

For example, an advertiser can create audiences of users who visited a website or a specific page, viewed a product page, added an item to their cart, interacted with a product but did not complete a purchase, or submitted a lead form.

These audiences can be used both to re-engage visitors and to exclude users who have already completed a desired action.

Website Retargeting supports a lookback window of 1 to 90 days, with 90 days as the default.

Building an audience requires accurate event transmission, compliance with user data requirements, and a sufficient number of matched users. Reddit's documentation specifies a minimum threshold of 50 users for Website Retargeting.

Engagement Retargeting

Engagement Retargeting focuses on users who have interacted with advertisements directly on Reddit.

Users can be included in an audience based on ad impressions, clicks, upvotes, comments, and video views.

For example, an advertiser can create an audience of users who watched at least half of a video ad but have not yet visited the website.

Engagement Retargeting does not require Reddit Pixel because the relevant interactions occur directly on the advertising platform. Reddit allows advertisers to use engagement history covering up to six months.

How It Worked Before

Before the August 2026 update, advertisers could create and use Website Retargeting and Engagement Retargeting audiences through Reddit Ads Manager.

In Audience Manager, advertisers could select a data source, define events, and configure the audience membership window.

The Ads API already supported certain Custom Audience operations, including managing Customer Lists.

However, the ability to programmatically create and delete Website Retargeting and Engagement Retargeting audiences specifically was limited.

This meant that even when campaign management was automated, some operations involving retargeting segments still had to be performed through the Reddit Ads Manager interface.

For agencies and advertisers working with large numbers of segments and accounts, this process created additional operational overhead.

What Changed in August 2026

Reddit added support for creating and deleting two types of retargeting audiences through the Custom Audiences API.

Website Retargeting uses the PIXEL_RETARGETING type, while Engagement Retargeting uses ENGAGEMENT_RETARGETING.

Developers can create audiences using the Create Custom Audience operation and delete them using Delete Custom Audience.

Depending on the audience type, the API allows developers to specify data sources, events, advertising campaigns, and lookback windows.

For example, Website Retargeting can use events such as PAGE_VISIT, VIEW_CONTENT, ADD_TO_CART, PURCHASE, or LEAD.

For Engagement Retargeting, available interaction types include CLICKS, IMPRESSIONS, UPVOTES, COMMENT_SUBMISSIONS, and different stages of video viewing.

As a result, Reddit has moved closer to the model commonly used by major advertising platforms, where audience management can be integrated into an agency's or advertiser's programmatic tools.

What Can Be Automated Through the Reddit Ads API?

• Creating segments using consistent rules. An agency can programmatically create standard retargeting audiences across multiple advertising accounts using predefined rules.
• Segmenting audiences by events. For example, separate audiences can be created for website visitors, users who added products to their carts, and purchasers.
• Managing lookback windows. Developers can set different audience membership periods depending on the audience type and advertising strategy.
• Creating segments based on ad engagement. Data on clicks, comments, and video views can be used to segment users by engagement level.
• Deleting outdated audiences. When campaign structures change, segments that are no longer in use can be deleted programmatically.

It is important to distinguish between creating an audience and populating it with users. Website Retargeting still depends on accurate event transmission through Reddit Pixel or CAPI. Creating an audience object through the API does not automatically populate it with users.

Additionally, the update does not mean that advertisers can upload arbitrary information about website visitors. The processing of user data remains subject to Reddit's requirements and applicable laws.

How the Update Relates to Automated Targeting

In 2026, Reddit also expanded its Automated Targeting capabilities.

Starting in August, the platform began rolling out automated targeting expansion for campaigns using Custom Audiences.

When this functionality is enabled, the advertising system may serve ads not only to users within the original audience but also to other users the algorithm considers promising prospects.

This is particularly important when evaluating the performance of retargeting campaigns.

An ad group using a Custom Audience with Automated Targeting enabled is not necessarily limited to users in the original segment.

Therefore, in experiments designed to evaluate the effectiveness of re-engaging a known audience specifically, advertisers should separately review targeting expansion settings and the actual options available for controlling audience reach.

Why the Update Matters for Performance Marketing

The expansion of the Reddit Ads API is primarily an infrastructure improvement.

For a small advertiser manually managing a few audiences, the change may have little noticeable impact.

However, for agencies, integrators, and large companies, it provides an opportunity to reduce manual operations and standardize retargeting management.

For example, an agency can develop a consistent set of segments for its e-commerce clients:

The creation of these segments can be partially automated through the Ads API without configuring each audience manually.

For B2B advertisers, a similar approach can be applied to audiences of service page visitors, users who engaged with video ads, and existing leads.

At the same time, the API does not change the underlying principles of audience targeting. It provides developers with a more convenient way to manage Reddit's existing advertising capabilities.

Limitations and Practical Risks

• Event quality. Website Retargeting depends directly on the correct implementation of Reddit Pixel and the Conversions API. Event tracking errors can result in incomplete or inaccurate audiences.
• Audience size. For smaller websites and narrowly defined segments, the number of matched users may be insufficient for effective ad delivery.
• Automated targeting expansion. When Automated Targeting is enabled, campaign reach may extend beyond the original audience. This must be considered in reporting and experiments.
• Privacy. The use of user events and identifiers must comply with applicable data protection regulations. Reddit specifically warns about restrictions associated with European regulations.
• No guaranteed performance improvement. The API simplifies operational processes, but it does not improve the retargeting algorithm itself or guarantee lower CPA or higher ROAS.

Conclusion

The August 2026 Reddit Ads API update expands programmatic management of retargeting audiences by introducing operations for creating and deleting Website Retargeting and Engagement Retargeting segments.

This is an important step in the development of Reddit Advertising as a platform that supports systematic campaign management through external tools and API integrations.

For marketing agencies and large advertisers, the update provides an opportunity to standardize audience structures, reduce manual operations, and integrate Reddit retargeting into their broader advertising automation infrastructure.

However, the update does not introduce a new targeting algorithm. Its value lies in making existing capabilities more accessible and easier to manage.

Sources

• Reddit Ads API: August 2026 Monthly Update
• Reddit Ads API: Version History
• Reddit Business Help: Custom Audiences
• Reddit Ads API: List User Custom Audiences