Zero-Party vs First-Party Data: The Differences and Why It Matters for Consent

A customer tells you they want to hear about running shoes. Your website later records that they viewed several pairs of hiking boots. Both interactions give you information about their interests, but one is deliberately provided, and the other is observed.

The distinction sounds simple, but it matters when you decide how to use the data. A preference someone has chosen to share is different from an interest you've assumed from their behavior. Even if both are stored in the same customer profile, they were collected in different ways. Knowing how each piece of information was collected helps you understand what data you hold and assess the requirements that apply to its use.

This guide explains how zero-party and first-party data differ, where they overlap, and what to consider for consent, disclosure, and retention.

What Is Zero-Party Data?

Zero-party data is information a person intentionally and proactively shares with a business. Rather than learning something from their behavior, you ask them.

For example, a customer might select their preferred clothing size, answer a product quiz, or choose which topics they want to hear about. In each case, the information comes directly from the person, provided deliberately.

The important distinction is how the information is collected, not what the information is about.

For instance, if you ask a customer what kinds of recipes they like and they choose “vegetarian,” that is zero-party data. You know their preference because they told you directly. This gives businesses a more direct way to understand what customers want. Instead of relying only on what someone clicks on or buys, they can use the preferences customers have chosen to share.

What Is First-Party Data?

First-party data is information your business collects directly from customers or website visitors through your own website, app, or other channels.

For example, when a customer creates an account and makes a purchase, your business may collect their account details and record what they bought. If they return to your website, you may also collect information about which pages they visit or which products they look at. All of this is first-party data because it comes from your business’s own interactions with the customer.

First-party data can include information customers deliberately provide, such as answers on a form, as well as information you observe, such as pages viewed or items purchased.

Zero-Party vs First-Party Data: What Are the Key Differences?

The main difference between zero-party and first-party data is how the information is obtained. Zero-party data is intentionally shared by an individual, while first-party data is collected directly through customer interactions and observations. Zero- and first-party data are not mutually exclusive. Information that someone deliberately provides through your website can be both.

The two labels describe different things. Zero-party data describes how information was provided: The person chose to share it. First-party data describes where it was collected: through your own direct relationship with the customer.

Here’s how zero-party and first-party data compare, and what to consider before using each.

Neither zero-party nor first-party data comes with automatic permission for every use. For example, if a customer shares a preference to receive product recommendations, that doesn’t mean you can use it for unrelated marketing. The same applies to information collected through your website. Collecting it directly does not mean you can use it however you want.

Before using customer data, make sure the intended use is consistent with what the customer was told and with any applicable consent or legal requirements.

How Does Consent Apply to Zero-Party and First-Party Data?

Consent is not determined by whether information is labeled zero-party or first-party data. What matters is how the data is collected and used, and which privacy laws apply.

Under the General Data Protection Regulation (GDPR), consent is one possible legal basis for processing personal data, but it's not the only one. Which one a business may be able to rely on depends on the circumstances.

However, tracking cookies and similar tracking technologies generally require prior consent under the ePrivacy Directive, even when the information they collect is first-party data.

In the U.S., most state privacy laws use an opt-out model rather than requiring prior consent for most data collection, though for some data types, such as sensitive data or data belonging to children, prior consent is usually required.

For zero-party data, the important question is what the person understood when they provided the information. If someone answers a product quiz to receive a recommendation, that does not automatically mean they have agreed to receive marketing emails or have their answers used for unrelated purposes.

Under many privacy laws, if you want to collect or use data for a new purpose, you need to obtain new consent, as existing consent only covers the active purposes the customer was notified when they agreed.

The same principle applies to first-party data. Collecting information through your own website does not give you unrestricted permission to use it. For example, if you use analytics or advertising technologies, you need to know what they collect and whether consent is required before they operate. If consent is required, visitors must be able to make that choice before the relevant tracking begins.

What Must Businesses Disclose About Zero-Party and First-Party Data?

Businesses should explain what personal data they collect, how they collect it, why they use it, and, where required, the legal basis for that use.

Whether information is deliberately provided or collected through your own interactions, customers need to understand how their personal data is being used. Someone may know what they have chosen to share, but not how you intend to use it. Information collected through website tracking may be less obvious still, which is why your disclosures need to reflect how each type of data is collected and used.

Disclosing Zero-Party Data Collection

When someone fills out a form or answers a product quiz, they can see what information they are providing. But that doesn't mean they know everything you intend to do with it.

For example, if you ask customers about their preferences to provide product recommendations, explain whether you also intend to use those answers for other purposes, such as email campaigns or advertising. The fact that someone chose to share a preference does not remove the need to explain how it will be used.

Disclosing First-Party Data Collection

When you collect first-party data through website activity, the collection itself may be less visible. A visitor may not realize that analytics tools are recording their activity or that an advertising pixel is sending information to another company.

Your privacy policy should therefore explain what data is collected and how it’s used, including relevant tracking and data sharing. If your website uses cookies or similar technologies, the information shown alongside visitors’ choices should also explain what those technologies do.

Data privacy regulations also typically include requirements for disclosures and user notifications. Under the GDPR, businesses must provide information about their processing of personal data, including its purposes, its legal basis, and how long the data will be kept or the criteria used to decide.

Under California law, businesses must also disclose how long they keep each category of personal information, or the criteria used to decide, and may not keep it longer than reasonably necessary for the disclosed purpose.

It’s important to know what laws apply to your business so the information provided to visitors and customers can be accurate.

How Long Can Zero-Party and First-Party Data Be Retained?

There is no fixed retention period for zero-party or first-party data. How long you can keep each depends on why it was collected and the data privacy laws that apply. Under the GDPR, personal data must not be kept longer than necessary for the purposes for which it is processed.

The retention period should therefore reflect the data's purpose, not its category. For example, a customer’s stated preference may be kept while it’s needed to provide personalized recommendations. Purchase records may need to be retained for accounting or legal purposes, while browsing activity collected for analytics may only be needed for a shorter period.

When data is no longer needed for the purpose it was collected for, delete or anonymize it, unless a legal requirement, such as accounting rules, or another purpose you have already disclosed still applies. Data counts as anonymized only if individuals can no longer be identified. Pseudonymized data is generally still personal data.

Consent withdrawal is another trigger. If you rely on consent for a use and the person withdraws it, you generally need to delete the data held for that use unless another legal ground applies.

A simple retention schedule that lists each data type, its purpose, and when it will be reviewed makes these decisions easier to apply.

How to Make Informed Decisions About the Data You Collect

Knowing whether data is zero-party or first-party gives you useful context about how it was collected. But the label alone doesn’t tell you how that information should be handled.

Consider what the person understood when the data was collected and how you plan to use it. This can help you determine whether consent is required, what needs to be disclosed, and how long the data should be kept.

Those decisions depend on knowing what data your website collects. Data obtained via forms and preference centers are easy to identify because visitors interact with them directly. Cookies and other tracking technologies can be harder to keep track of as your website changes.

This is where a consent management platform (CMP) can help. Cookiebot™ CMP scans websites to identify the cookies and trackers in use. Knowing what's running on your site makes it easier to spot gaps, keep your disclosures accurate, and give visitors the right consent choices.