Third-party cookies: detailed guide & news, insights for 2026

Third-party cookies have played a major role in how online advertising and tracking work – but they’re also at the center of some of the biggest changes happening on the web today.

In this article, we’ll break down what third-party cookies are, how they work, and why they’ve been so important for marketers. You’ll learn how to enable or block them, check whether a website uses them, and understand their role in affiliate marketing. We’ll also look at how they differ from first-party cookies, what’s changing as browsers like Chrome phase them out, and how this all ties into compliance.

If you’re looking for clear, practical answers about third-party cookies, you’re in the right place.

In other words, they are data files that a browser stores on a user’s device, created by a domain different from the one the user is visiting. These cookies are most commonly introduced via embedded content, such as advertisements, analytics scripts, or social media widgets, hosted on the third-party’s servers and integrated into the primary website’s code. 

Third-party cookies example: you visit a website to check out a pair of glasses, and a third-party cookie from an ad network like Facebook is placed in your browser. Later, while browsing other sites, you see ads for those same glasses or similar styles because the cookie tracks your visit.

Their technical function enables third-party domains to track a user’s behavior across multiple websites over time, forming the foundation of cross-site tracking.

Cookies collect data such as browsing patterns, preferences, and sometimes personal details. Advertisers and marketing companies use this information to build comprehensive user profiles, which they use for targeted advertising. These cookies allow advertisers to deliver personalized ads across various websites, improving the efficiency and impact of online marketing efforts.

In affiliate marketing, cookies are crucial in determining which ads should be served to the right audience at the right place and time.

Here is an overview of what benefits third-party cookies offer to digital marketing:

• Audience insights. Third-party cookies offer detailed information on user behavior across different websites. This information allows marketers to understand user interests, behavior, and patterns. 
• Targeted advertising. Third-party cookies make precise ad targeting possible, ensuring the perfect fit between the ad message, the time, and the place.
• Retargeting campaigns. Third-party cookies let brands re-engage users who showed interest in the offering but did not convert, boosting ROI.
• Affiliate marketing. Third-party cookies track conversions, attributing conversions or sales to the correct affiliate. This promotes transparency and fair compensation calculations.
• Cross-platform tracking. Third-party cookies give insights into a user's journey across different devices and platforms. This helps create a smooth, cohesive customer journey that polishes a brand's marketing and advertising campaigns. 

With increasing restrictions on third-party cookies, their impact on digital marketing is clear. Marketers must find alternatives and adjust to these changes to keep their strategies effective. 

For many, this change would disrupt long-established marketing strategies.

Let’s get through the steps of third-party cookie operation. 

Step 1. Initial request

When a user loads a webpage with third-party content (for example, from an external ad network), the user’s browser sends a request to the third-party server to retrieve that content.

Step 2. Cookie creation

Next, the third-party server sends back a cookie that includes data like a unique user ID, timestamps, and other tracking information.

Step 3. Cross-site tracking

When a user visits other websites with cookies from the same third party, the server can access them in their browser. This allows the server to recognize users and track their activity across websites. As a result, a detailed profile of a user’s browsing habits is created. 

Step 4. Ad serving

Based on the created user profile, advertisers serve targeted ads that align with the user’s preferences and past online behavior. It increases the chances of user conversion. 

3rd-party cookies are created by domains other than the one you are currently visiting. When you visit a website, that site may include content from external sources, such as ads, embedded videos, or analytics tools. These external sources can place cookies on your browser, even though you’re not directly interacting with them. 

For example:

• First-party cookies are set by the website you’re actively browsing.
• Third-party cookies are set by external services or domains (e.g., advertising networks, analytics providers) embedded in the site.

These cookies can track your online activity across multiple websites, enabling targeted advertising, cross-site analytics, and personalization.

If you need to add third-party cookies to your website, here is how to do it.

Understand the legal grounds

Third-party cookies fall under regulations like GDPR, CCPA, and other global or regional privacy laws. Before implementing them on your website, it’s essential to understand and comply with the relevant legal requirements. Even if your region has no specific restrictions, your users may come from areas with stricter rules.

These regulations are designed to increase transparency and protect user privacy by preventing unethical or unregulated tracking. Websites that don’t clearly disclose what data is collected or how it’s used can face penalties. This includes information such as cookies and IP addresses, which can identify users even when they browse anonymously.

Set a cookie consent banner

Before collecting users’ information using cookies, you must obtain their consent. To do so, you need to implement a cookie banner. Our blog has an all-in-one cookie banner guide, so we won’t discuss it now. Instead, we recommend you refer to the guide for details. 

Set the goals of third-party cookies

What are third-party cookies going to help you accomplish? In other words, think through the collected data applications. It can include:

• Advertising. Meta pixel or Google Ads use cookies to target ads and to track conversions. 
• Analytics. Google Analytics or similar services can provide detailed insights on website usage. 
• Other. Chatbots, embedded videos, and social sharing buttons can use third-party cookies. 

Integrate third-party cookies (consent mode)

The next step is to add the necessary scripts to your website's HTML to set the cookies. 

You have to do it in the <head> or <body>.

Test your implementation

Check if cookies are being set using your browser's developer tools. In Chrome DevTools, follow these steps:

• Open Chrome Developer Tools (right-click anywhere on the page and select Inspect, or use Ctrl+Shift+I / Cmd+Option+I).
• Navigate to the Application tab.
• Expand Storage in the left-hand menu and select Cookies.
• Choose the domain from the list you want to inspect.
• Review the displayed cookies to verify their details, including name, value, domain, and expiration date.

Monitor performance

Keep an eye on your website’s performance and verify that cookies are functioning as intended. Use tools like GTM, GA4 DebugView, or third-party testing services to monitor and test cookie behavior effectively.

You can check whether a website uses third-party cookies in several ways. 

Browser settings

Most browsers have a privacy or security section in their settings where you can view cookies stored by websites. Look for entries under domains other than the main website's domain.

Browser Extensions

Some browser extensions can tell you whether a website uses cookies or other scripts. For example, uBlock, primarily an ad blocker, also provides information on scripts and cookies used on websites. Such extensions are easy to install and provide quick insights into a site's cookie usage.

Chrome DevTools

A more tech way to check for cookies would be to use Chrome DevTools.

1. 1.
   Open Chrome Developer Tools: right-click on the webpage, select Inspect, or press Ctrl+Shift+I (Windows/Linux) or Cmd+Option+I (Mac).
2. 2.
   Go to the Application tab in the developer tools.
3. 3.
   In the left-hand menu, expand Storage and select Cookies.
4. 4.
   You will see a list of domains. Select each domain to view its cookies.
5. 5.
   Look for cookies with domains different from the website you are visiting. These are third-party cookies.

Blocking third-party cookies is one of the easiest and most effective ways to prevent cross-site tracking, limit personalized ads, and reduce the amount of data shared with advertisers. Most modern browsers like Chrome, Safari, and Firefox now offer built-in settings to block these cookies and enable strict tracking protection.

To block third-party cookies, follow these steps based on the browser you are using:

For Google Chrome:

1. Go to Settings. Go to Privacy and Security. 

2. Choose Cookies and other site data.

3. Select Block third-party cookies.

For Mozilla Firefox:

1. Open Settings. Go to Privacy & Security.

2. Under Enhanced Tracking Protection, choose Strict or customize to block third-party cookies.

For Microsoft Edge:

1. Go to Settings. Move to Privacy, search, and services.

2. Under Tracking Prevention, select Strict.

For Safari (macOS/iOS):

1. Open Preferences. Go to Privacy.

2. Enable Prevent cross-site tracking.

For Opera:

1. Go to Settings. Go to Privacy & security. Go to Cookies and site data.

2. Enable Block third-party cookies.

Blocking third-party cookies improves privacy. This is true. However, it may negatively affect the user's website performance. 

1. 1.
   Google’s (un)decisive decision on cookies. Chrome disables third-party cookies for 1% of users in 2024, causing major panic in the digital world. Initially, Google planned to stop using third-party cookies in its Chrome browser but changed its mind. Now, they let users decide whether to block or allow them. This change came after advertisers worried about losing personalized ads.
2. 2.
   Privacy Sandbox. The Privacy Sandbox and its related APIs are privacy-focused tools from Google designed to replace cookies. Chrome introduced the Protected Audience API (formerly known as FLEDGE) as part of the Privacy Sandbox. This in-browser API allows advertisers and ad tech companies to display interest-based ads without third-party cookies while protecting users from cross-site tracking.
3. 3.
   Searching for safer options. Businesses aren’t waiting for cookies to disappear. Instead, they’re collecting data directly from their customers (like through loyalty programs or subscriptions) to rely less on third-party cookies.
4. 4.
   Privacy rules and oversight. Authorities worldwide are watching Google’s actions closely to ensure they don’t harm competition or privacy. Global data privacy regulations require companies to give up on using third-party cookies.
5. 5.
   New ways to measure ads. With cookies becoming less reliable, companies are looking at alternative methods to track ad performance, such as "attention metrics." These metrics assess how much time users spend engaging with ads, how often they interact with them, and the overall level of focus or interest. Advertisers can gain deeper insights into how well their ads capture attention and drive meaningful interactions by measuring engagement rather than just clicks or impressions.

In short, while Google third-party cookies are still around, the industry is still moving toward better privacy and new ways of targeting and measuring ads replying to zero-party and first-party data. Our blog also provides more information on zero-party vs first-party data on our blog. 

Third-party cookies have been the biggest tool for tracking user behavior for years, but with privacy regulations tightening worldwide, they’ve become a bit of a headache. Plus, more and more browsers (like Chrome, Safari, and Firefox) are blocking them, which makes things even trickier for businesses. 

Server-side tracking is the solution, and Stape makes it easy to set up. It lets you use first-party cookies to control your data and simplify privacy compliance. It can be configured for various platforms, including server-side Google Analytics, Google Ads, Meta, and many other platforms.

With server-side tracking, you can still collect essential data for your marketing but in a way that respects users' privacy and preferences. Thus, it’s a win-win: effective tracking without the constant cookie drama.

Let us give you an example of how server-side tracking with Stape can help your business. 

We have power-ups that make cookies last longer.

Cookie Keeper

Keeps cookies safe on the server, so they don’t get deleted or blocked by browsers. Stape offers standard cookies for Pro plan users and as for Business-tier users and above, you can also use any additional custom cookies.

Custom Loader

Custom Loader makes Google Tag Manager and Google Analytics scripts harder to block by ad blockers and ITP. It changes how gtag.js and gtm.js are loaded. It also works with Custom Domain to set first-party cookies and extend their lifetime.

Let’s compare first-party cookies and third-party cookies.

For businesses in 2026, relying on first-party cookies is a safer choice. While we cannot tell you to throw Chrome 3rd party cookies out of the picture, it’s wise to have options other than relying solely on them. First-party cookies offer better privacy protection, make it easier to comply with data laws, and create a smoother user experience. While third-party cookies offer some benefits for targeted advertising, they also present increasing challenges and risks. Focusing on first-party data and using privacy-first tracking methods will help you stay ahead in a more privacy-conscious digital world. 

We answered the most common questions on third-party cookies you might have in 2026. 

Third-party cookies remain crucial to marketing strategies. They fuel insights and personalization. However, as privacy regulations multiply and become tougher, and browser restrictions and tracking prevention tools become more substantial, the future of third-party cookies isn’t guaranteed. To get the most out of cookies while you still can is a good strategy, but finding alternatives that can withstand the demands of a privacy-centered world is essential as well.