First-party vs third-party data in 2026: what changed, and what to do about it

Who this is for: marketers, founders and agencies deciding what data to build their marketing on.

What you'll learn: the difference between first-party and third-party data, what actually happened to third-party cookies, why first-party data still matters more, and how to start collecting it from your own website.

For years the story was simple: third-party cookies are going away, so build your own data before they do. Then, in 2025, Google changed course. Chrome kept third-party cookies, and Google retired the Privacy Sandbox, its planned replacement. So is first-party data still worth the effort?

Yes, and for better reasons than a deadline.

In short: Third-party data is information about people collected by someone else and sold or shared with you. First-party data is what you collect yourself, from your own website, forms, customers and conversations. Chrome still allows third-party cookies, but Safari and Firefox block them, a large share of people use ad blockers, and the data you rent from a platform is its data, not yours. First-party data is the part you own, it describes your own buyers rather than an average audience, and it gets more valuable the longer you collect it. Bread & Butter turns your website into a first-party data source: every visit recorded from the first one, joined into one journey per person, scored, and attached to the lead the moment they tell you who they are.

The difference

Third-party data is collected by a company you have no relationship with, then sold, shared or rented to you. Audience segments from a data broker, interest categories from an ad platform, and contact lists from a database are all third-party data. It's broad and quick to buy, but it isn't about your buyers, and you can't check where it came from.

First-party data is what you collect directly: who visits your website and what they do there, who fills in your forms, who opens your emails, who buys. It's narrower, but it's about the people who actually engage with you, and you control it.

Zero-party data is a subset of first-party data that someone gives you on purpose, such as preferences in a sign-up form or answers to a quiz.

What happened to third-party cookies

In April 2025, Google announced it would keep its current approach to third-party cookies in Chrome and would not roll out the standalone choice prompt it had planned. In October 2025, it retired the Privacy Sandbox technologies that were meant to replace them.

So third-party cookies still work in Chrome. That doesn't mean they work everywhere:

  • Safari and Firefox block third-party cookies by default.
  • Safari keeps adding protections. Link Tracking Protection strips tracking parameters from links in Mail, Messages and Private Browsing, and from iOS 26, Safari's advanced fingerprinting protection is on for all browsing, not just private windows.
  • Ad blockers are common. GWI's data for the second quarter of 2025 puts ad blocker use at 29.5% of internet users worldwide.
  • Consent laws such as GDPR in Europe and state privacy laws in the US keep narrowing what can be collected and shared without permission.

The reprieve in Chrome means third-party data didn't disappear overnight. It still covers less of the web every year.

Why first-party data matters more anyway

It's about your buyers. A third-party segment describes an average audience that looks roughly like your customers. First-party data describes the people who actually came to your site, read your pricing page and bought.

You own it. The audiences an ad platform builds are its data, not yours. It can change what you see, what it costs, or whether you see it at all.

It compounds. Every visit, every conversion and every closed deal adds to what you know. A contact list is at its best on the day you buy it; your own data gets better the longer you collect it.

It's cheaper over time. Acquisition costs keep rising for most teams. First-party data helps on both sides: it shows which campaigns bring buyers, so less is wasted on the ones that don't, and it helps you keep the customers you already have, because you know what they came back for.

It's easier to defend. Data people gave you directly, on your own site, under your own privacy policy, is simpler to explain to a customer and to a regulator than data bought from someone you've never met.

Where first-party data usually falls short

Most websites already collect some first-party data, but it's scattered. Analytics counts sessions but doesn't know who anyone is. The form captures an email but none of the visits before it. The CRM has the contact but not what they read. Nobody has the whole story.

The gap is the time before someone fills in a form. For most buyers that's most of the journey: several visits, from several sources, over days or weeks.

How Bread & Butter turns your website into a first-party data source

Every visit, from the first one. Bread & Butter records each visit on your site and joins them into one journey per person: the pages they read, the order they read them in, how long they stayed, how far they scrolled, and what brought them each time.

Attached to the lead when they tell you who they are. When someone fills in one of your existing forms, subscribes or signs in, their whole history arrives with them. See How Bread & Butter works with your existing forms & subscribe widgets

Scored. Focused Score ranks every visitor 1 to 10 against the others on your site, so you can see which ones are serious before they convert. See What is Focused Score and how does it evaluate my traffic?

Yours. The journeys recorded on your site belong to you, and we don't resell them. See Who owns the data I collect, and do you resell it?

Sent where you work. Leads go to your CRM, Slack, email tools or anywhere else through Zapier or a webhook, with their journey attached. See Integrations and Automation: what you can send, where, and when

Where to start

  1. Collect what you already have a right to. Your own website visits, forms and customers come first.
  2. Join it up. A visit, a form and a CRM record that describe the same person should be one profile, not three.
  3. Be clear about what you collect and why. Keep your privacy policy current and make opting out easy.
  4. Use it to spend less, not only to target more. The biggest early win is usually cutting the campaigns that bring traffic but no buyers.

Common questions

Are third-party cookies gone?

Not in Chrome. Google decided in 2025 to keep them. Safari and Firefox already block them by default, and ad blockers and privacy settings remove more.

Is first-party data the same as first-party cookies?

No. First-party cookies are one way a website remembers a visitor. First-party data is everything you collect directly, including forms, purchases and conversations.

Does Bread & Butter replace Google Analytics?

It doesn't have to. Analytics counts traffic. Bread & Butter tells you which visitors were serious, joins their visits into one journey, and attaches that journey to the lead. Many teams run both.

Sources

Did this answer your question? Thanks for the feedback There was a problem submitting your feedback. Please try again later.