What is first-party data in marketing?

First-party data is data your own business collected: purchases, sign-ups, email addresses, subscription status, support history, on-site behavior. You own the relationship it came from, which is what separates first-party data from data bought or borrowed from someone else. Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. The shoe workshop owns a customer's checkout email, the customer's $180 order, the customer's size, and whether the customer bought a second pair. That is first-party data.

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

First-party data comes from your direct relationship with the person. Third-party data was collected by another company and made available to advertisers, historically through cookies and data marketplaces. Browser and platform changes have made the third-party version far less usable.

Glossary

First-party data

First-party data is information you collected yourself from your own customers and visitors, with their consent, such as emails from checkout, order history, and account details. It is yours. Third-party data is information a different company collected elsewhere. First-party data is what you still have when browsers stop sharing cookies (small files that follow people across other companies' sites).

Theodor Lindfors, Founding Marketer · September 14, 2026

What counts as first-party data

Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. Almost everything the shoe workshop already stores about a customer is first-party data, as long as the customer gave it in the relationship with the shoe workshop, not via a list the shoe workshop bought.

Transactions: orders, refunds, subscription status, plan tier. A customer's $180 pair, and the return of a too-narrow size.
Identity you were given: email, phone, account details.
Behavior on properties you own: site, app, product usage. Which product pages a customer opened.
Stated preferences: survey answers, preference centre choices.
CRM records (customer relationship software): pipeline stage, close date, deal value. More typical for a sales-led company, still first-party data.

Why first-party data matters

Advertising measurement used to lean on identifiers shared across the web. That layer has thinned out, and what remains is the data each business collected for itself. That is why enhanced conversions and Conversions API both ask you to supply it. Google and Meta want a shoe workshop's hashed emails (fingerprints of addresses, not the raw emails) because they can no longer follow a customer around the internet as easily.

First-party data is also better data. First-party data knows margin, refunds, repeat purchases, and LTV (lifetime value: how much a customer spends over their life with you). A platform pixel (a snippet of code in the browser) knows a conversion fired. A shoe workshop's records know a customer came back six months later for a second pair.

How to use first-party data

Two jobs. Feed first-party data back to platforms for matching and optimization, so bidding chases the customers you actually want. And use first-party data internally to judge campaigns on real revenue instead of the platform's version of events. A shoe workshop can tell Google to look for people like its repeat buyers, not like one-time window shoppers.

Consent has to travel with first-party data. Collected with permission for one purpose does not mean usable for every purpose, and that constraint is a compliance matter before it is a marketing one. An email given so the shipping confirmation can arrive is not automatically an email you may upload as an ad audience.

Common first-party data mistakes

Owning a lot of first-party data and never connecting it to ad platforms or reporting.
Uploading customer lists without checking the consent basis.
Leaving first-party data scattered across a shop, a billing tool, and a warehouse that never speak.
Treating an email list as a substitute for measurement. An email list is an input, not an answer.

Lemonado

How Lemonado helps with first-party data

First-party data (information you collected from your own customers) is useful when it sits next to ads. Lemonado connects CRM (customer relationship software), commerce, and ad accounts so lifetime value, repeat rate, and paid results can be asked in one place.

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