First-Party vs Second-Party vs Third-Party Data (2026)

First-party data is information a company collects directly from its customers — website visits, purchases, app usage, and CRM records. Second-party data is another organization’s first-party data shared through a partnership. Third-party data is aggregated from external sources by data brokers. Understanding the differences between these three data types is essential for building a privacy-compliant, accurate customer data strategy.

Key takeaways:

• First-party data is the most accurate and valuable because you collect it directly with customer consent
• Second-party data extends your audience reach through trusted partner relationships
• Third-party data offers scale but carries higher privacy risk and lower accuracy
• Zero-party data is a subset of first-party data that customers proactively volunteer
• Privacy regulations and the deprecation of third-party cookies are making first-party data the foundation of modern data strategy

First-Party vs Second-Party vs Third-Party Data Comparison

The core difference between first-party, second-party, and third-party data is the relationship between the data collector and the customer. First-party data comes directly from your customers, second-party data comes from a partner’s customers, and third-party data comes from unknown sources via aggregators. This distinction determines data accuracy, privacy compliance, and strategic value.

First-Party Data

First-party data is the most valuable data type because you collect it directly from your customers and can verify its accuracy, relevance, and privacy compliance. It comes from interactions on your own channels — your website, mobile application, CRM, support systems, and marketing programs. Examples of first-party data include demographics, purchase history, website activity, email engagement, sales interactions, support calls, customer feedback programs, interests, and behaviors.

It’s not hard to collect first-party data. All our customer-related systems collect some customer data. The challenge is that they all gather, store, and manage it differently, leading to inaccurate and inconsistent data in some systems. The best way to ensure your customer data is consistent across all your systems is to leverage a central platform, such as a customer data platform, to consolidate, standardize, and make it available to all systems regardless of where it was first collected.

Second-Party Data

Second-party data is essentially another company’s first-party data, shared with you through a direct partnership or data marketplace. In most cases, you know the partner, which means you know the data quality and accuracy. You also know the data is relevant because it comes from a partner with whom you have a mutually beneficial relationship.

Equally important, your partner also complies with data privacy regulations like the GDPR and the CCPA, so you can be confident the information was collected with the permission of the consumers in the dataset.

You can also buy second-party data by connecting with partners through data marketplaces. When you acquire data this way, you can discuss the data with the partner and select only the information you want. If you decide to go this route, you can be sure the marketplace is trustworthy, the partners you are connected with are reliable, and their data is collected and managed correctly.

There are a few benefits to using second-party data:

• It enables you to scale by connecting with new audiences that match your own audience data.
• You can combine it with your first-party data to build improved predictive models. This is especially true when you don’t have a lot of customers from which to develop predictive models.
• You can develop better audience insights by analyzing a more extensive audience group. Combining your first-party data with second-party data may help you find new ways to reach your audience or find new audiences to reach out to.

One example of second-party data is the data media publishers sell to advertisers. Another example is a grocery store selling its customer loyalty data to a credit card company.

Collecting second-party data is straightforward; you get it from the partner. Once you have it, you need to manage second-party data the same way you do first-party data, which means you need to store it securely and make it available through the same methods to your systems. You should also validate and clean your second-party data the same way you do your first-party data, to ensure it’s accurate and relevant.

Third-Party Data

Third-party data is purchased from data aggregators who compile information from multiple external sources without a direct relationship to the individuals described. Data aggregators do not collect data directly but obtain it from other companies and compile it into a single dataset. As a result, the data can come from many different data sources, some large, others small, and there’s not always a clear definition of the audience that data comes from.

Most third-party data is purchased through a DSP (demand side platform) or a DMP (data management platform) for advertising. There are also many third-party data marketplaces, including Acxiom, Nielsen, and OnAudience.

There are several reasons you might want to purchase third-party data:

• It helps you reach a broad audience for your advertising programs.
• When combined with your first-party data, it can help you improve targeting.

Third-party data is bought and sold programmatically, and it’s usually very large datasets. The biggest concern with this data is that you do not know where it came from, so you can’t ensure its reliability or accuracy. You also can’t be sure it was collected according to privacy regulations. Therefore, when you select a third-party data provider, you must do your research and understand where and how the data was collected.

What Is Zero-Party Data?

Zero-party data is information that customers intentionally and proactively share with a brand, such as preferences, purchase intentions, and personal interests. Coined by Forrester Research, zero-party data is defined as “data that a customer intentionally and proactively shares with a brand, which can include preference center data, purchase intentions, personal context, and how the individual wants the brand to recognize her.”

Examples of zero-party data include data a consumer explicitly provides, such as communication preferences or the types of information they want to receive. Interests are another example, with a consumer explicitly telling you what things they are interested in, such as craft beer, products for toddlers, or things to do on road trips.

Not everyone believes we need another data type, especially not one that suggests an even more direct source to the customer. Still, it’s a term we hear increasingly often, and therefore, it’s one you should understand.

Zero-party data is a component of first-party data and must follow all the rules around managing it. It also provides the same benefits as other data, including enabling you to create personalized, relevant experiences.

How Privacy Regulations Are Reshaping Data Collection

Privacy laws and the end of third-party cookies are accelerating the shift toward first-party data as the foundation of customer strategy. Companies that rely heavily on third-party data face growing regulatory risk, while those that invest in first-party data collection gain a durable competitive advantage.

Privacy Becomes Even More Important

Consumers are tired of being bombarded with irrelevant content and advertising. Many are choosing not to provide their data to companies because they don’t understand how their information is being used and if it’s properly (and securely) managed.

Privacy regulations like GDPR in the EU, CCPA in California, and dozens of state-level and international privacy laws mean that it is becoming increasingly important that companies collect customer data appropriately and are transparent on how that data will be used. They also need to follow through on how they use data to improve customer experiences.

The Cookieless Era and Its Impact on Data Strategy

Third-party cookies are no longer a reliable data source. Major browsers have restricted or eliminated third-party cookie tracking, and Apple’s App Tracking Transparency gives consumers the ability to opt out of cross-app tracking on iOS devices. This shift fundamentally changes how companies collect and activate customer data.

Companies need to prioritize alternative approaches: asking people to register and identify their preferences and interests, leveraging progressive profiling to slowly grow your customer dataset, creating highly targeted advertising on social media platforms, and investing in contextual advertising that does not rely on individual tracking.

Building Your First-Party Data Strategy

A strong first-party data strategy is the foundation of every effective data program — second-party and third-party data supplement it, but cannot replace it. The first step is to understand your requirements for customer experiences across the entire organization. Once you know what you want to do, you can figure out what types of data you need to implement those experiences.

Next, you need a way to bring all your data together — first-, second-, third-, and zero-party data — so it can be validated, cleansed, standardized, and compiled to make available to everyone who needs it. A customer data platform provides the data unification layer that makes this possible.

It’s also time to start planning alternative approaches to data that you may soon have no access to. The key will be to develop new strategies to get first-party (and zero-party) data.

Finally, it’s critical to be testing and measuring the impact of your data constantly. This will never be a “set-it-and-forget it” situation. You will always need to think of new ways to collect and update data, stop collecting specific data, start collecting others, integrate new source systems, and more.

Want to learn more about how to choose the right customer data platform for your organization? Our comprehensive guide explores the key steps needed to create a successful CDP evaluation and selection process — from the capabilities to consider, to the questions you should ask prospective vendors to make sure you’re making the right decision. Access your copy of our guide here.

FAQ

What is the difference between first-party and third-party data?

First-party data is collected directly from your customers through your own channels, making it highly accurate and privacy-compliant. Third-party data is purchased from aggregators who compile information from multiple external sources, resulting in lower accuracy, unknown consent status, and limited relevance to your specific business. The key distinction is the direct relationship with the customer.

Why is first-party data more valuable than second-party or third-party data?

First-party data is the most valuable because you collect it directly from your customers with verified consent. You can confirm its accuracy, relevance, and compliance with privacy regulations. Unlike second-party or third-party data, it reflects actual interactions with your brand and does not require trust in an external party’s data collection practices.

What is zero-party data and how is it different from first-party data?

Zero-party data is information that customers intentionally and proactively share with a brand, such as communication preferences and purchase intentions. While it is technically a subset of first-party data, the distinction is that zero-party data is explicitly volunteered by the customer rather than observed or inferred from their behavior. The term was coined by Forrester Research.