Postback

Server-to-Server (S2S) integration refers to the direct communication between two backend systems without any client-side (browser or app) intermediary. In mobile app monetization and marketing, S2S integrations are used for real-time data exchange between a developer's backend and third-party services such as attribution providers, analytics platforms, payment processors, and ad networks. Common use cases include sending purchase events from a web checkout server to an MMP for attribution, forwarding subscription lifecycle events (renewals, cancellations, refunds) from a billing provider to an analytics platform, and transmitting conversion signals from a payment processor to advertising platforms for campaign optimization. S2S integrations are more reliable and privacy-compliant than client-side tracking methods because they don't depend on user-side factors like ad blockers, browser cookies, or SDK availability. For web-to-app flows, S2S architecture is particularly important — it enables the web payment system to communicate subscription status to the app's backend, which then provisions access for the user regardless of which platform or device they use.

A Mobile Measurement Partner (MMP) is a third-party analytics platform that provides independent attribution, analytics, and measurement services for mobile app marketing campaigns. MMPs track which ad clicks and impressions lead to app installs and post-install events, providing a unified view of marketing performance across multiple ad networks and channels. Major MMPs in the mobile ecosystem include AppsFlyer, Adjust, Branch, Singular, and Kochava. MMPs play a neutral intermediary role — since they are independent from both the advertiser and the ad networks, their attribution data is considered unbiased. Core MMP capabilities include last-touch attribution, multi-touch attribution, fraud detection, deep linking, audience segmentation, SKAdNetwork management, and cohort-based analytics. In the post-ATT landscape, MMPs have evolved to offer probabilistic modeling, predictive analytics, and aggregated measurement solutions that work within Apple's privacy constraints. For subscription apps, MMPs provide critical insights into which channels and campaigns deliver subscribers with the highest LTV, enabling marketers to shift budget toward the most profitable traffic sources.

SKAdNetwork (SKAN) is Apple's privacy-preserving attribution framework for measuring the effectiveness of advertising campaigns that drive app installs on iOS. Introduced as an alternative to IDFA-based tracking after ATT severely limited user-level tracking, SKAN provides aggregated, anonymized attribution data directly from Apple's servers — without revealing any information about individual users. Under SKAN, when a user clicks an ad and installs an app, Apple validates the install and sends an attribution postback to the ad network after a delay, containing limited information: the ad network ID, campaign ID, and a conversion value set by the developer. The conversion value (initially 6 bits allowing 64 possible values, expanded in SKAN 4.0 with coarse and fine values) is the developer's only mechanism for encoding post-install user behavior into the attribution signal. This means developers must carefully decide which events to encode — such as whether the user started a trial, made a purchase, or reached an engagement threshold — within a constrained time window. SKAN's design prioritizes user privacy through delayed, aggregated reporting with built-in noise, which makes campaign-level optimization significantly more challenging than traditional attribution methods.

Mobile attribution is the process of connecting app installs and in-app actions to specific marketing campaigns, ads, or channels that drove them. It enables marketers to understand which advertising efforts deliver results, optimize ad spend across channels, and make data-driven decisions about user acquisition strategies.

Event-based attribution is a method of crediting marketing channels or campaigns based on specific post-install events that a user completes, rather than attributing value solely at the point of install. While traditional mobile attribution focuses on which ad or campaign drove the app install, event-based attribution goes deeper by tracking downstream actions like free trial starts, subscription purchases, in-app purchases, or reaching a specific engagement milestone. This approach is particularly valuable in the post-ATT landscape where install-level attribution data is limited. By shifting focus to post-install events, marketers can better evaluate which channels drive high-quality users who actually convert and generate revenue, rather than just volume of installs. Event-based attribution works in tandem with SKAdNetwork's conversion value framework, where developers can encode specific post-install events into the limited conversion value bits available. It also enables more sophisticated optimization of ad campaigns, since platforms like Meta and Google can optimize toward deeper funnel events when provided with conversion signals tied to revenue-generating actions.