First-Party vs Third-Party Cookies: A Guide for Website Owners

Cookies are small text files that websites store in your visitors' browsers. They have been a fundamental part of how the web works since the mid-1990s. But the way cookies are treated by browsers, regulators, and users has changed dramatically in recent years.

If you own or manage a website, you need to understand the difference between first-party and third-party cookies. Not because it is an interesting technical topic, but because it directly affects your analytics, your advertising, your legal obligations, and how your website functions.

This guide explains the difference in plain terms, covers the browser changes that are reshaping the cookie landscape, and gives you practical steps for adapting your website.

What Is a First-Party Cookie

A first-party cookie is set by the website the visitor is currently on. When someone visits your website at yourdomain.com, any cookie set by yourdomain.com is a first-party cookie.

First-party cookies serve essential functions:

Session management. When a visitor logs into your website, a first-party cookie keeps them logged in as they navigate between pages. Without it, they would need to re-enter their password on every page.

Preferences. If your site lets visitors choose a language, a theme, or a display preference, a first-party cookie remembers that choice.

Shopping carts. E-commerce sites use first-party cookies to track what is in a visitor's cart as they browse products.

Analytics. When you use a first-party analytics tool, it sets a cookie on your domain to distinguish between new and returning visitors. Google Analytics 4, for example, sets the _ga cookie on your domain.

Form data. Some forms use cookies to save partially completed information so visitors do not lose their progress.

First-party cookies are generally considered less problematic from a privacy perspective because they only work on your site. The cookie set by yourdomain.com cannot be read by anotherdomain.com. The data stays within the relationship between your website and your visitor.

That said, first-party cookies are not exempt from privacy regulations. Under GDPR, you still need consent for non-essential first-party cookies, such as analytics or personalization cookies. Only cookies that are strictly necessary for the site to function - like session cookies for a login system - can be set without consent.

What Is a Third-Party Cookie

A third-party cookie is set by a domain other than the one the visitor is currently on. When someone visits yourdomain.com, but a cookie is set by facebook.com, google.com, or ad-network.com, those are third-party cookies.

Third-party cookies exist because modern websites load resources from many different domains. When your page includes a Facebook Like button, a Google Analytics script, an advertising pixel, an embedded YouTube video, or a live chat widget, each of those services can set its own cookies in the visitor's browser.

Here is where it gets important: third-party cookies can track visitors across multiple websites. When ad-network.com sets a cookie on your site, and then the same visitor goes to another site that also uses ad-network.com, the ad network can connect those visits. Over time, this builds a detailed profile of the visitor's browsing habits.

This cross-site tracking capability is the reason third-party cookies have become the central battleground in privacy debates.

Common Sources of Third-Party Cookies on Websites

Most website owners do not realize how many third-party cookies their site sets. Here are the usual suspects:

• Advertising platforms: Google Ads, Meta Pixel, LinkedIn Insight Tag, Twitter Pixel
• Analytics services: Some analytics implementations set third-party cookies, particularly older Universal Analytics setups
• Social media embeds: Like buttons, share buttons, and embedded social feeds
• Video embeds: YouTube, Vimeo, and other video players
• Chat widgets: Live chat and support tools
• Font services: Google Fonts and Adobe Fonts (these transfer data even if they do not always set cookies)
• Retargeting tools: Services that show your ads to previous visitors on other sites
• Affiliate tracking: Affiliate networks that track referral sources

Why Browsers Are Blocking Third-Party Cookies

The major browsers have been moving to block third-party cookies for several years now. Here is where things stand.

Safari

Apple's Safari browser started blocking third-party cookies by default in 2020 through its Intelligent Tracking Prevention (ITP) feature. Safari now blocks all third-party cookies and also limits the lifespan of some first-party cookies set through JavaScript to 7 days. If the cookie is set by a domain classified as a tracker, the limit drops to 24 hours.

Safari's approach has been the most aggressive, and since it is the default browser on iPhones and Macs, it affects a significant portion of web traffic - roughly 20 to 30 percent in most markets, and higher on mobile.

Firefox

Mozilla's Firefox browser blocks third-party tracking cookies by default through its Enhanced Tracking Protection feature. This has been the default setting since 2019. Firefox uses a list of known trackers maintained by Disconnect to decide which third-party cookies to block.

Firefox also introduced Total Cookie Protection in 2022, which creates a separate cookie jar for each website. Even when a third-party cookie is allowed, it is partitioned so that facebook.com's cookie on site-a.com is separate from facebook.com's cookie on site-b.com. This prevents cross-site tracking.

Chrome

Google Chrome is the last major browser to address third-party cookies, which makes sense given that Google's advertising business depends on them. After several delays and reversals, Chrome has landed on a hybrid approach.

As of 2025, Chrome gives users more visible control over third-party cookies through its Privacy Sandbox initiative and the Tracking Protection feature. Chrome has been gradually rolling out third-party cookie restrictions, though the timeline has been slower than Safari or Firefox.

The practical effect is that third-party cookies are becoming unreliable across all major browsers. Even in Chrome, where they still function for many users, the direction is clear: the era of unrestricted third-party cookie tracking is ending.

Other Browsers

Brave blocks all third-party cookies by default and has done so since launch. Edge follows a similar approach to Chrome with its tracking prevention feature. Opera and Vivaldi offer various levels of cookie blocking.

What This Means for Your Website

The death of third-party cookies has practical implications for several areas of your website.

Impact on Analytics

If you use Google Analytics, the core functionality is based on first-party cookies, so it will continue to work. However, some features that relied on third-party cookies - particularly cross-domain tracking and certain attribution models - may be less accurate.

The bigger issue is that Safari's 7-day limit on JavaScript-set first-party cookies means that returning visitors who come back after more than a week may be counted as new visitors. This inflates your new visitor count and makes it harder to understand returning visitor behavior.

To mitigate this, consider setting analytics cookies server-side rather than through JavaScript, or use analytics tools that handle this automatically.

Impact on Advertising

This is where the changes hit hardest. Third-party cookies powered three key advertising functions:

Retargeting. Showing ads to people who visited your website. Without third-party cookies, traditional retargeting becomes much less effective.

Conversion tracking. Measuring whether someone who clicked your ad actually completed a purchase. Many conversion tracking systems relied on third-party cookies to connect the ad click to the conversion.

Audience targeting. Building audiences based on browsing behavior across multiple sites. This type of targeting is fundamentally broken without cross-site cookie tracking.

The advertising industry is adapting through alternatives like Google's Topics API, server-side conversion tracking, first-party data strategies, and contextual advertising. But the transition is messy, and many small businesses are seeing changes in their ad performance as a result.

Impact on Consent Requirements

Here is something that surprises many website owners: blocking third-party cookies does not eliminate your consent obligations. Even in a world where browsers block third-party cookies, you still need consent for non-essential first-party cookies under GDPR.

Your analytics cookies, personalization cookies, and any first-party cookies used for marketing purposes still require consent. The browser changes reduce the privacy risk of cookies overall, but they do not change the law.

For guidance on building a compliant consent banner, see our guide on GDPR banner examples.

How to Check What Cookies Your Website Uses

Before you can address cookie issues, you need to know what cookies your site is setting. There are several ways to do this.

Manual Browser Inspection

Open your website in Chrome, then open Developer Tools (F12 or right-click and select Inspect). Go to the Application tab, then click Cookies in the left sidebar. You will see a list of all cookies organized by domain. Cookies from your own domain are first-party. Cookies from any other domain are third-party.

This method works but has limitations. You only see cookies set during your specific browsing session. If you have already consented to cookies, you will see the full set. To see what loads before consent, open your site in an incognito window and check before interacting with any consent banner.

Automated Scanning

A website scanner provides a more complete picture. Automated tools crawl your site, load multiple pages, and identify all cookies and tracking technologies across the entire site - not just the page you happened to check manually.

Find out what cookies your website uses with a free Scanibly scan. The report categorizes each cookie as first-party or third-party, identifies the service that sets it, and flags any cookies that load before consent.

Practical Steps for Website Owners

Here is what you should do in response to the shifting cookie landscape.

Step 1: Audit Your Current Cookies

Run a scan to identify every cookie and tracker on your site. Categorize them as first-party or third-party, essential or non-essential. This gives you a clear picture of your starting point.

Step 2: Remove Unnecessary Third-Party Cookies

Look at each third-party cookie and ask whether you actually need the service that sets it. That social sharing widget you added three years ago that nobody uses? Remove it. The analytics tool you installed but never check? Remove it. Every unnecessary third-party service is both a privacy liability and a performance drag.

Step 3: Replace Third-Party Solutions With First-Party Alternatives Where Possible

Some common replacements:

• Google Fonts (external CDN) to self-hosted fonts. Download the font files and serve them from your own domain. No more requests to Google's servers.
• YouTube embeds to privacy-enhanced embeds. Use youtube-nocookie.com instead of youtube.com for embedded videos.
• Third-party comment systems to native comments. If you use a service like Disqus, consider switching to your platform's built-in comment system.
• External analytics to privacy-friendly alternatives. Tools like Plausible or Fathom use no cookies at all.

Step 4: Implement Proper Cookie Consent

Regardless of browser changes, you need a consent mechanism that:

• Blocks non-essential cookies until the visitor consents
• Provides clear categories (necessary, analytics, marketing, etc.)
• Offers an easy way to accept all, reject all, or customize
• Records consent for audit purposes
• Allows visitors to change their preferences later

If you use Squarespace, our guide on Squarespace cookie banner setup walks through the process for that platform.

Step 5: Build First-Party Data Relationships

As third-party tracking becomes less effective, the value of first-party data increases. First-party data is information people give you directly: email subscriptions, account registrations, purchase history, survey responses.

Focus on building direct relationships with your audience:

• Offer genuine value in exchange for email signups (not just "subscribe to our newsletter")
• Create accounts and loyalty programs that give people a reason to identify themselves
• Use server-side analytics and conversion tracking where possible
• Invest in contextual advertising rather than behavioral targeting

Step 6: Update Your Privacy Policy

Your privacy policy should accurately describe the cookies your site uses. After removing unnecessary cookies and making changes, update your privacy policy to reflect the current state. List the cookies by category, explain what each does, and state how long they persist.

Step 7: Monitor Regularly

Cookie landscapes change. Plugin updates can introduce new cookies. New features can add new trackers. A regular scanning schedule catches these changes before they become compliance issues.

The Future of Cookies

The web is moving toward a model where first-party relationships matter more and third-party tracking matters less. This is driven by browser changes, privacy regulations, and growing consumer awareness.

For website owners, this is ultimately a positive shift. It rewards businesses that build trust directly with their audience and reduces the advantage of data brokers and surveillance-based advertising.

The transition period is bumpy. Advertising effectiveness is harder to measure. Analytics are less precise. Consent management adds friction. But these are manageable challenges, especially if you understand what is happening and take proactive steps.

Start by understanding your current cookie situation. Scan your website for cookie issues and get a clear report of what your site sets, when it sets it, and whether your consent mechanism is working properly. That knowledge is the foundation for everything else.