Zero-Party Data vs First-Party Data for Ecommerce

Every zero-party data article on page one was written as a response to “the death of the third-party cookie”. Then Google changed course. In April 2025 it said it would keep its current approach to third-party cookies in Chrome rather than roll out a new opt-out prompt (Google Privacy Sandbox blog). If cookies were the only reason to care, the topic would be over.

They were never the main reason for an ecommerce brand. Zero-party and first-party data matter because they are what your email and SMS programme runs on. This guide covers what each one is, how they differ, and how to collect them through quizzes, sign-up forms and preference centres.

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What is zero-party data?

Zero-party data is information a customer intentionally and proactively shares with you: their preferences, goals, purchase intentions and how they want to hear from you. Quiz answers, preference-centre choices and survey responses are the classic examples. Because the customer chose to tell you, it is the most accurate personalisation data an ecommerce brand can hold.

The term was coined by Forrester analyst Fatemeh Khatibloo, who described it as data a customer proactively shares, often in the expectation that it will be used to give them a better experience. That expectation is the important part. Zero-party data comes with an implied deal: “I told you what I want, now use it.”

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First-party vs zero-party vs second-party vs third-party data

Type	What it is	How you get it	Ecommerce examples	Main use
Zero-party	What customers tell you on purpose	Asking: quizzes, forms, preference centres, surveys	Skin type, fitness goal, flavour preference, “email me about launches only”	Personalisation, routing, product recommendations
First-party	What you observe on your own channels	Your store, email, SMS, site, support	Orders, products viewed, carts, clicks, returns, reviews	Segmentation, triggers, prediction
Second-party	Another company’s first-party data, shared with you	A direct partnership agreement	A co-branded giveaway’s opt-ins, a retail partner’s shared insights	Audience expansion with a known source
Third-party	Data compiled by companies with no direct customer relationship	Data brokers, ad networks	Inferred interests and demographics for ad targeting	Prospecting in paid media

Many practitioners treat zero-party data as a subset of first-party data, since both are collected directly. The distinction that matters in practice: first-party data tells you what someone did; zero-party data tells you what they want and why. A customer who bought a magnesium supplement might want better sleep, less muscle cramping or lower stress. Their order history cannot tell you which. One quiz question can.

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What is first-party data?

First-party data is information you collect from your own audience on channels you own. For a store, that means:

• Transactional: orders, products, variants, order value, discount codes, refunds, subscription status.
• Behavioural: product and category views, site searches, cart and checkout events.
• Engagement: email and SMS clicks, sign-up source, form interactions.
• Service: support tickets, returns reasons, reviews.

It is the backbone of ecommerce retention. Every flow trigger (placed order, started checkout, viewed product), every customer segment and every predictive field in Klaviyo is built on it.

Why first-party data matters more than the cookie debate suggests

Third-party cookies are still blocked by default in Safari and Firefox, so a large share of shoppers on Apple devices were never trackable that way. Apple’s Mail Privacy Protection makes email opens unreliable. Ad platforms reward advertisers who send them better first-party conversion signals. And privacy law in the EU, UK, Australia and many US states keeps tightening the rules on data you did not collect directly.

None of that stopped when Google kept Chrome’s cookies. For a DTC brand the conclusion is the same as it was: the data you own is the data you can rely on.

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Zero-party data examples for ecommerce

• Supplements: health goal (sleep, energy, gut health, recovery), dietary requirements, capsule or powder preference, flavour.
• Skincare and beauty: skin type, concerns, sensitivities, routine length, shade.
• Apparel: size, fit preference, style, who they shop for.
• Food and coffee: roast, brewing method, allergies, household size.
• Pet: species, breed, age, dietary needs.
• Communication: preferred channel, frequency, topics (“launches only”, “recipes”, “sales”).
• Purchase intent: “buying for myself or a gift”, “shopping for an event on a date”, “what made you look today”.

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How to collect zero-party data

1. Product quizzes

The richest collection point. A good quiz asks five to eight questions, recommends a product or routine, and captures an email (and optionally a phone number) before or alongside the result. Every answer becomes a profile property you can segment and personalise on. We cover quiz design, tools and supplement and skincare examples in quiz funnels for list growth.

Quiz tools such as Octane AI integrate with Klaviyo and pass answers across as custom profile properties, plus a quiz-completed event you can trigger flows on (Octane AI help centre).

2. Multi-step sign-up forms

You do not need a separate quiz tool to start. Klaviyo’s sign-up forms support multiple steps, so the first step captures the email and the second asks one question: “What are you shopping for?” with three or four buttons. Keep it to one or two questions; every extra field costs conversions. Our pop-up best practices guide covers timing and offers.

3. The welcome series

Ask in the first or second welcome email: “Tell us what you’re after and we’ll send the right things.” Each button click sets a property or adds the profile to a segment. This catches everyone who skipped the second form step.

4. Post-purchase surveys

Right after the first order, ask how they heard about you and what they are hoping the product does for them. The first answer helps attribution; the second powers product onboarding and the post-purchase flow.

5. Preference centres

A preference page lets subscribers choose topics, frequency and channels instead of unsubscribing outright. In Klaviyo, options added to a list’s subscribe and preference pages are saved as profile properties you can segment on (Klaviyo Help Center, consent pages). Link it from every email footer and from your sunset flow.

6. Account and replenishment moments

Account creation, subscription sign-up and reorder reminders are natural moments to confirm or update preferences: “Still on the vanilla? Want to try chocolate this month?”

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A zero-party data question bank

A starting template. Pick one or two questions per collection point, never all of them.

Question	Where to ask	What it powers
What are you shopping for today?	Sign-up form step two	Welcome branch, first product featured
What’s your main goal? (sleep, energy, recovery…)	Quiz, welcome email	Product recommendation, education content
What’s your skin or hair type?	Quiz, sign-up form	Routine recommendation, cross-sell
Any dietary requirements or sensitivities?	Quiz	Exclusions: never recommend what they can’t use
Buying for yourself or as a gift?	Sign-up form, post-purchase	Gift reminders versus replenishment
How did you hear about us?	Post-purchase survey	Attribution sense-check
What do you hope this product does for you?	Post-purchase survey	Onboarding flow, review request timing
How often do you want to hear from us?	Preference centre, sunset flow	Frequency caps, fewer unsubscribes
Which topics interest you? (launches, recipes, sales)	Preference centre	Campaign segment membership
Email, SMS or both?	Preference centre	Channel routing

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Building a zero-party data strategy in five steps

1. Start from the decision. List the messaging decisions you would make differently if you knew something about the customer: which product to feature, which welcome branch, whether to send SMS. Only collect what changes a decision.
2. Choose the collection points. Map each question to the moment the customer has a reason to answer: browsing (form or quiz), just bought (survey), about to leave (preference centre).
3. Standardise the properties. Decide the property names and allowed values once (“goal” = sleep, energy, recovery) so segments do not break when a form is edited. Free-text answers are hard to segment; use buttons.
4. Wire the data to flows before launch. A quiz answer that no flow uses is wasted. Build the welcome branches and segments at the same time as the form.
5. Refresh it. Preferences change. Ask again at natural moments (a year on, at a subscription milestone, in the sunset flow) and let the most recent answer win.

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How to use it once you have it

Collecting zero-party data and then sending everyone the same email breaks the implied deal. Put it to work in four places:

1. Welcome routing. Branch the welcome series by stated goal or type, so the first emails feature the right products and proof.
2. Segmented campaigns. Launches go first to the people who said they care about that category.
3. Dynamic content. Swap hero products, tips and testimonials inside one campaign based on the property.
4. Frequency and channel. Respect “launches only” and “email not SMS”. It lowers unsubscribes and protects deliverability.

Combine it with first-party behaviour for the most useful segments: “said their goal is sleep and bought once and is 10 days past their expected reorder date” is a message that practically writes itself.

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Consent and sensitive data

Zero-party data is volunteered, but it is still personal data. Three rules keep you on the right side of customers and regulators:

• Say why you are asking and use it only for that purpose.
• Keep marketing consent separate from the quiz or survey itself. Answering a quiz is not consent to email; the opt-in has to be explicit.
• Be careful with health data. For supplement and wellness brands, questions about symptoms or conditions can count as health information. Under UK and EU GDPR, data concerning health is special category data with stricter conditions (ICO guidance), and Australia’s Privacy Act treats health information as sensitive information (OAIC key concepts). Ask about goals (“better sleep”) rather than conditions (“insomnia diagnosis”) unless you have the legal basis and safeguards to handle the latter.

This section is general information, not legal advice.

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How to tell whether it is working

• Completion rate of each question or quiz step, and conversion to opt-in.
• Share of active profiles with at least one zero-party property.
• Revenue per recipient of personalised versus generic sends to the same segment.
• Unsubscribe and complaint rates after introducing preference options.
• Second-purchase rate for customers routed by stated goal versus not.

If profiles are filling up but nothing downstream changes, you have a data project, not a marketing one.

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Where to start

Add one question to the second step of your main sign-up form, and route the first two welcome emails on the answer. It is a one-afternoon build and it tells you quickly whether your audience will share more.

If you want help designing the collection points and the flows that use them, our list growth team builds forms, quizzes and lead magnets that grow a list of buyers rather than bystanders, and our retention marketing work turns that data into repeat orders. Or start with a free Klaviyo audit.

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Sources

• Google Privacy Sandbox, next steps (April 2025)
• Klaviyo Help Center, getting started with consent pages
• Octane AI Help Center, personalising Klaviyo with Octane AI data
• ICO, special category data
• OAIC, APP guidelines chapter B: key concepts