What are postbacks?

A postback is the exchange of information between servers to report a user’s action on a website, network, or app. In the context of the mobile app ecosystem, a postback is a ping to the ad network when any app install or in-app conversion event is detected. Postbacks enable marketers and advertisers to measure campaign performance and optimize their strategies.

Mobile measurement partners (MMPs) will typically notify advertisers of specific event data via postbacks. Branch also triggers postbacks for specific subsections of events, and these postbacks can be filtered by link data, user data, or event properties. For example, if a user clicks on a mobile ad and later installs the advertised app, the MMP may send a postback to the advertiser, providing information about this conversion event, including when and where it occurred.

Types of postbacks

Advertisers tend to focus on two types of postbacks:

  • Install postbacks which notify the ad source when a user installs a mobile app after clicking on an advertisement, allowing for the attribution of app downloads to specific marketing campaigns.
  • In-app event postbacks which notify the ad source about an in-app event once the app has been installed. In-app events can include purchases, registrations, add to cart events, checkouts, content views, and more.

Why do postbacks matter?

Postbacks are crucial because they provide a valuable feedback loop for advertisers and marketers to optimize their ad campaigns in real time:

  1. Campaign attribution: Postbacks help verify data across devices, ad networks, and other MMPs accurately and effectively, enabling advertisers to attribute specific user actions to the appropriate channels or campaigns.
  2. Budget efficiency: By improving the verifiability of attribution data, postbacks support more accurate CPI-based billing and help optimize ad spends and improve ROAS on paid channels.
  3. Optimization: Advertisers use postback data to be more data-driven in their decision-making, identifying the most effective strategies and reallocating resources to maximize ROI.
  4. User insights: With improved visibility into post-install activity, postbacks help advertisers and marketers understand user behavior.
  5. Retargeting: By analyzing postback data, advertisers can drive successful retargeting campaigns by honing in on users who are more likely to engage and convert.

How do postbacks work?

Postbacks work by facilitating communication or notifications between an advertiser’s MMP or ad network and the app’s server. The feedback loop typically follows this flow:

  1. A user engages with an ad by clicking on it, and the MMP records the action.
  2. The MMP generates a unique postback URL containing information about the user’s action and the ad campaign, which is then sent to the app’s server.
  3. The app’s server processes the data in the URL, which often includes details about the ad sources, the user, and the specific action.
  4. Based on this data, the app’s server triggers a postback, sending information back to the MMP to confirm the action (or conversion). This postback data is used for attribution, campaign measurement, and reporting.

Postbacks and SKAdNetwork (SKAN)

To ensure advertising operations are compliant with the privacy policies of leading mobile platforms, savvy advertisers today must keep abreast with ever-evolving technicalities and best practices around the kinds of data that is shareable within postbacks.

For example, SKAdNetwork, Apple’s framework developed to protect user privacy while still allowing advertisers to measure campaign performance, severely limits the amount of data shared with advertisers. Instead of sharing granular user data, SKAN sends aggregated data about campaign performance to protect user’s identities. This approach is intended to comply with Apple’s App Tracking Transparency (ATT) framework. Released as a part of iOS 14.5, ATT effectively split the entire postback mechanism governing iOS campaigns into two buckets: those from consenting iOS users and those from non-consenting iOS users.

As privacy-centric measurement becomes an industry requirement, advertisers and app developers need to adapt their tracking and attribution methods to comply, while still leveraging postback data to make data-driven decisions about their campaigns. Luckily, MMPs like Branch bridge the gap between user-level postback data and aggregated SKAN data, providing advertisers with usable insights about their campaigns.