What is Privacy Sandbox?
Privacy Sandbox is Google's multi-year initiative to replace third-party cookies and cross-app identifiers with new privacy-focused APIs. These technologies aim to support advertising use cases like targeting, measurement, and fraud prevention while limiting individual-level tracking.
The initiative spans both Chrome (web) and Android (mobile), representing the largest shift in digital advertising infrastructure in decades.
Privacy Sandbox APIs
| API | Use Case | How It Works |
|---|---|---|
| Topics API | Interest-based targeting | Browser assigns user to ~350 interest topics |
| Protected Audiences (FLEDGE) | Remarketing | On-device auctions without server tracking |
| Attribution Reporting | Conversion measurement | Aggregated attribution without user IDs |
| Private Aggregation | Cross-site reporting | Aggregate data with differential privacy |
| Shared Storage | Cross-site data | Limited storage with privacy protections |
Android Privacy Sandbox
For mobile apps, Android Privacy Sandbox introduces similar concepts optimized for the app ecosystem:
Key Android APIs
- Topics: Returns user interests based on app usage (not individual apps)
- Protected Audiences: Custom audience targeting without cross-app tracking
- Attribution Reporting: Install and post-install attribution with privacy
- SDK Runtime: Isolated SDK environment for privacy
Industry Impact
Privacy Sandbox represents a fundamental shift in how advertising works. MMPs, DSPs, and advertisers must adapt their technology stacks and measurement strategies to the new reality.
Topics API Deep Dive
The Topics API is the primary interest-based targeting mechanism:
- Topic Assignment: Browser/device assigns user to topics weekly
- Topic Selection: Up to 5 top topics per user per week
- Topic Retrieval: Advertisers get 1 random topic per site/app
- Privacy Noise: 5% chance of random topic for privacy
- Epoch Reset: Topics recalculated weekly
Attribution Reporting API
| Feature | Event-Level | Aggregate |
|---|---|---|
| Data Detail | Limited conversion data | Aggregate statistics |
| Privacy | Noisy, delayed | Differential privacy |
| Use Case | Optimization signals | Campaign reporting |
| Timing | 2-30 day delay | Batched reports |
Pro Tip: Start Testing Now
Privacy Sandbox APIs are available for testing. Start integrating and learning now—advertisers who adapt early will have a significant advantage when third-party cookies fully deprecate.
Preparing for Privacy Sandbox
- Audit Current Reliance: Identify where you use third-party cookies/GAID
- Build First-Party Data: Strengthen owned data assets
- Test New APIs: Participate in Privacy Sandbox origin trials
- Update SDKs: Ensure your tech partners support new APIs
- Develop New Strategies: Plan for aggregate measurement
- Educate Teams: Train on new concepts and limitations
Privacy Sandbox vs. SKAN
| Aspect | Privacy Sandbox (Android) | SKAdNetwork (iOS) |
|---|---|---|
| Platform | Android | iOS |
| Approach | New APIs, gradual rollout | Immediate enforcement |
| Targeting | Topics API available | No targeting API |
| Attribution | Event + Aggregate | Postbacks only |
| Industry Input | Collaborative development | Apple-defined |