With the introduction of Apple's App Tracking Transparency (ATT) framework in iOS 14.5, users are now required to give explicit consent for apps to track their activity across other apps and websites for advertising purposes. This has resulted in a substantial decrease in the number of iOS users sharing their Identifier for Advertisers (IDFA), with estimates as high as 34%.

At YouAppi, we’ve innovated a data-driven strategy to reach a greater number of iOS users with a privacy-compliant dual approach that leverages both probabilistic and deterministic mobile data. By applying multiple layers of data to cast a wide targeting net, we’ve reached more than 50% of iOS users with retargeted mobile ads.

Read about our approach to learn privacy compliant strategies for filling the data gaps left by the deprecation of the IDFA.

What is Dual Opt-In?

The dual opt-in approach for App Tracking Transparency (ATT) refers to the requirement for users to opt-in twice for their data to be used for advertising purposes on another app: once from the advertiser and once from the publisher.

To scale growth despite the deprecation of the IDFA, many DSPs have found ways to blend deterministic and probabilistic data to target and customize ads. This dual opt-in approach buckets opt-in types based on whether a user has consented to share their IDFA on the demand side, supply side, or both.

A Step-by-Step Approach to Building a Dual Opt-in Strategy

#1: Launch an App Tracking Transparency (ATT) Consent Prompt 

Securing user permission to access their Identifier for Advertisers (IDFA) is a first initial step for an iOS retargeting campaign. This involves implementing an App Tracking Transparency (ATT) consent prompt.

The ATT prompt queries users on whether they permit the app to track their activities across different apps and websites. Despite the minimal customization options available for developers on this prompt, enhancing user understanding through pre-permission prompt can be beneficial. This preliminary prompt offers a more detailed explanation of opt-in benefits, enhancing consent rates.

Implementing a pre-permission prompt is advisable to elevate opt-in rates while adhering to Apple's guidelines, which include restrictions on the call-to-action (CTA) options and incentivization tactics.

Here are Apple’s requirements to keep in mind:

  • Pre-prompts are limited to one CTA like “Read More,” “I understand,” or “Continue.”
  • The CTA must directly open the system alert. This prevents developers from asking a user for their consent to share their IDFA more than once.
  • Apps are forbidden from offering incentives or compensation in return for ATT consent.

2. Adopt a Dual Consent Strategy

In the face of IDFA's declining availability, a strategy blending both probabilistic and deterministic data can be effective. This dual consent approach allows for precise ad targeting and customization.

This strategy distinguishes between users based on their consent level—whether it's on the demand side, the supply side, or both. Utilizing a mix of data signals based on the user's consent category enables more targeted ad campaigns.

At YouAppi, the data signals we use depend on which opt-in bucket the user falls into.

  • Dual Consent: When a user selects “Allow” to an advertiser tracking their activity on both the demand and supply side. Currently, the average dual consent opt-in rate is ~30%. These users can be retargeted with ads on both the supply and demand side using deterministic data.
  • Demand Side Consent: When a user selects “Allow” to an advertiser tracking their activity on the demand side but not on the supply side. Live demand side postbacks are collected from these users. From there, users are segmented and bid on programmatically using a mix of contextual and behavioral data signals. If we add demand-side to dual consent, we can reach a demand-side opt-in rate as high as 50%.
  • Fully Probabilistic: Users that have not opted-in to sharing their IDFA on either the demand or supply side.  Probabilistic data identifies and retargets ads to these users.

Layering Data Signals for Enhanced Scale 

To enhance advertisers' reach on iOS amidst the challenges posed by Apple's App Tracking Transparency (ATT) framework, YouAppi employs a layered data approach. By combining deterministic and probabilistic data, we cast a wide targeting net, in specific cases reaching over 50% of iOS users with retargeted mobile ads. This strategy involves leveraging dual consent, demand-side consent, and fully probabilistic data signals to categorize users based on their consent levels. Through this approach, advertisers can target users more precisely, maximizing the effectiveness of their campaigns.

For a real example of how we’ve used a layered data approach to scale our re-engagement of iOS users, watch our fireside chat with Playstudios at IMS 2023.

3. Embrace Patience and Conduct Thorough Testing

Achieving the revenue levels seen before the iOS 14.5 update demands patience and rigorous testing. Mobile marketers need to continually optimize and test various campaign elements to discover effective strategies that yield positive Return On Advertising Spend (ROAS).

Understanding and adapting to the distinct trends of iOS user behavior, as opposed to Android, is essential. Monitoring these trends carefully over time ensures that campaigns are moving towards increased efficiency and effectiveness.

4. Focus on Creative Enhancement

The shift away from IDFA has highlighted the importance of creative strategy in campaign optimization. In the absence of granular user data, compelling ad content has become increasingly crucial for engaging users.

Investing in creative development and conducting A/B testing on these creatives can maximize campaign performance. For brands lacking in-house creative capabilities, collaboration with a DSP that offers creative support is beneficial.

Employing these strategies has proven successful in increasing the reach and effectiveness of iOS retargeting campaigns, as demonstrated by significant user engagement improvements post iOS 14.5+.


Navigating the new landscape of iOS advertising requires a thoughtful and compliant approach. YouAppi's experience in leveraging both deterministic and probabilistic data within the constraints of Apple's App Tracking Transparency framework has effectively reached 50% of users on iOS platforms:

  1. Dual Opt-In Efficacy: The dual opt-in strategy bridges the gap left by the deprecation of IDFA, enabling precise ad targeting and customization while respecting user privacy. This approach not only complies with Apple's requirements but also opens up new avenues for engaging with iOS users.
  2. Creative Engagement: With IDFA access restricted, the emphasis on creative strategy has never been more critical. Investing in engaging, high-quality ad content and conducting thorough A/B testing are pivotal to capturing and retaining user interest.
  3. Patience Pays Off: Adapting to iOS 14.5's changes is a long-term endeavor. Commitment to testing, optimization, and adapting strategies based on evolving user trends is key to achieving sustainable growth and a positive return on advertising spend.
  4. Maximizing Opt-In Rates: Implementing a pre-permission prompt alongside the mandatory ATT prompt can significantly enhance opt-in rates. This provides a foundation for more targeted and effective retargeting campaigns.

By focusing on these areas, marketers can navigate the challenges introduced by ATT and IDFA deprecation, ensuring their campaigns continue to reach and resonate with iOS users.


Ready to elevate your iOS retargeting strategy? Reach out to our team to maximize your reach on iOS today!