What is the difference between a real-time and a persistent identity graph?

How does a real-time identity graph resolve identities differently?

A real-time identity graph resolves identities at the moment of interaction, matching incoming signals such as email addresses, device IDs, or cookies against a broader identity graph to recognize an individual instantly. This happens in milliseconds, without requiring prior knowledge of that specific user stored in your own system.

Rather than relying on pre-built customer records, a real-time graph queries live connections across a network of identity data sources the moment a signal arrives. This makes it particularly powerful for recognizing anonymous or partially known visitors the instant they land on a website, open an app, or engage with an ad.

The practical benefit is immediacy. When a user arrives with only a hashed email or a device identifier, a real-time identity graph can connect that signal to a broader profile and return enriched insights before the page even finishes loading. This enables personalization, fraud detection, and audience targeting without waiting for a batch process to catch up.

What is a persistent identity graph and how is it maintained?

A persistent identity graph is a continuously maintained, long-term record that links all known identifiers for an individual into a single, unified profile. Unlike a real-time lookup, a persistent graph accumulates and updates identity connections over time, building a comprehensive view of each person across their digital and offline touchpoints.

Maintaining a persistent graph requires ongoing data ingestion and reconciliation. As new identifiers appear, such as a new device, a changed email address, or an offline purchase, the graph must update existing records and merge or split profiles accordingly. This process relies on several key identity graph data sources:

First-party data collected directly from customers

Offline data such as purchase history or loyalty program records

Cross-device signals that connect mobile, desktop, and connected TV activity

Authenticated identifiers like email addresses and phone numbers

A well-maintained persistent identity graph becomes more accurate over time, making it the foundation for long-term customer intelligence, segmentation, and audience building across channels.

Which type of identity graph is better for personalization?

For personalization, the most effective approach combines both types. A persistent identity graph provides the depth of customer knowledge needed to deliver relevant experiences, while a real-time identity graph ensures that knowledge is applied at the exact moment it matters most. Neither alone delivers the full picture.

A persistent graph tells you who someone is based on their history. A real-time graph ensures you can act on that knowledge instantly, even when the person arrives through an unfamiliar identifier or an anonymous session. Together, they power a cross-device identity graph that recognizes people consistently whether they are logged in or not, on mobile or desktop, in-store or online.

For identity graph marketing, this combination means you can greet a returning customer with a relevant offer the moment they arrive, rather than treating them as a stranger simply because they switched devices or cleared their cookies.

How FullContact helps with building an identity graph

We built our Resolve platform specifically to bridge real-time recognition and persistent identity in a single, privacy-safe solution. Our identity graph spans over a decade of authenticated and behavioral data, enabling businesses to recognize individuals instantly while maintaining a rich, continuously updated profile for each person. Here is what that means in practice:

Real-time API responses in under 150 milliseconds for live identity resolution

900+ personal and professional attributes appended to customer records

Persistent identity profiles that connect online and offline data sources

Privacy-safe architecture that never requires you to share your customer data

Whether you are trying to personalize at the moment of arrival or build smarter long-term audience segments, we can help you put the right identity infrastructure in place. Contact us to explore how our identity graph can work for your business.