What Is the Difference Between First-Party and Third-Party Cookies in GDPR?

Understanding Cookie Types

Cookies are small text files stored on users' devices that websites use to remember information between visits. Under GDPR, not all cookies are created equal - the regulation treats first-party and third-party cookies differently based on their origin, purpose, and privacy implications.

Understanding these distinctions is essential for GDPR compliance because the type of cookie directly affects consent requirements, user privacy impacts, and regulatory risk.

What Are First-Party Cookies?

Definition

First-party cookies are set directly by the website domain you are visiting. When you browse example.com, any cookies set by example.com or its subdomains (www.example.com, shop.example.com) are first-party cookies.

Common Purposes

First-party cookies typically serve essential website functions:

Session Management:

• Login authentication and user sessions
• Shopping cart contents across pages
• Form data persistence during multi-step processes
• Language and region preferences

Site Functionality:

• User interface customization
• Accessibility settings
• Layout preferences
• Volume controls for media players

Analytics (First-Party):

• Understanding user behavior on your own site
• Tracking navigation paths
• Measuring conversion funnels
• Performance monitoring

Technical Characteristics

Set-Cookie: session_id=abc123; Domain=example.com; Path=/; Secure; HttpOnly

Key attributes:

• Domain: Matches the current website domain
• Path: Typically / for site-wide access
• Secure: Transmitted only over HTTPS
• HttpOnly: Not accessible via JavaScript (security)

Privacy Implications

First-party cookies generally have lower privacy risks:

✅ Limited tracking scope: Data stays within single website ✅ Clear ownership: Website owner controls the data ✅ User expectations: Visitors expect functional cookies ✅ Easier consent: Some categories exempt from consent requirements

What Are Third-Party Cookies?

Definition

Third-party cookies are set by domains different from the website you're visiting. When browsing example.com, any cookies set by analytics.com, ads.com, or other external domains are third-party cookies.

Common Sources and Purposes

Advertising Networks:

• Google Ads (doubleclick.net)
• Facebook Pixel (facebook.com)
• Programmatic ad platforms
• Retargeting and remarketing

Analytics Platforms:

• Google Analytics (when loaded from Google's domain)
• Adobe Analytics
• Third-party analytics providers

Social Media Widgets:

• Facebook Like buttons
• Twitter/X embedded feeds
• LinkedIn share buttons
• Social login integrations

Content Delivery:

• Video players (YouTube embeds)
• Embedded maps (Google Maps)
• Chat widgets (Intercom, Drift)
• Comment systems (Disqus)

Technical Characteristics

Set-Cookie: tracking_id=xyz789; Domain=.ads.com; Path=/; Secure

Key distinguishing features:

• Domain: External domain (not matching current site)
• Set by embedded scripts, iframes, or pixel requests
• Persists across multiple websites
• Enables cross-site tracking

Privacy Implications

Third-party cookies pose higher privacy risks:

⚠️ Cross-site tracking: Follow users across different websites ⚠️ Behavioral profiling: Build detailed user profiles over time ⚠️ Data aggregation: Combine data from multiple sources ⚠️ Unknown processing: User doesn't control third-party practices ⚠️ Hidden tracking: Often invisible to users

GDPR Treatment: Key Differences

Consent Requirements

First-Party Cookies:

Under GDPR and ePrivacy Directive, consent requirements depend on purpose:

Strictly Necessary (Exempt from Consent):

• Authentication and session management
• Shopping cart functionality
• Security features
• Load balancing
• Fraud prevention

Non-Essential (Require Consent):

• Marketing and analytics cookies
• Personalization beyond basic functionality
• Performance optimization cookies
• A/B testing cookies

Key Point: First-party cookies serving essential functions are exempt from consent requirements, but non-essential first-party cookies (analytics, marketing) require consent just like third-party cookies.

Third-Party Cookies:

GDPR mandates that websites cannot store third-party cookies without explicit user consent:

• ❌ No pre-loading before consent
• ✅ Must obtain opt-in consent
• ✅ Requires granular consent options
• ✅ Easy consent withdrawal

Exception: Strictly necessary third-party cookies (rare, e.g., fraud prevention services essential for site operation) may be exempt, but the bar is very high.

Legal Basis

First-Party Cookies:

Can potentially rely on multiple legal bases:

1. Legitimate Interest: For analytics and performance cookies (requires Legitimate Interest Assessment)
2. Contract: Session cookies necessary for service delivery
3. Consent: Marketing and personalization cookies
4. Legal Obligation: Cookies required by law (rare)

Third-Party Cookies:

Typically require consent as primary legal basis:

• Legitimate interest generally insufficient for third-party tracking
• Data sharing with external parties requires explicit user agreement
• Cross-site tracking incompatible with user expectations
• High privacy risk level necessitates active consent

2025 GDPR Requirements

First-Party Cookie Banners Should:

✅ Distinguish necessary from non-necessary cookies ✅ Allow granular consent for analytics/marketing ✅ Clearly explain purposes ✅ Provide easy consent withdrawal ✅ Not load non-essential cookies before consent

Third-Party Cookie Banners Must:

✅ Explicitly identify third-party services ✅ Explain data sharing and purposes ✅ List third-party recipients by name ✅ Provide granular opt-in/opt-out ✅ Equal prominence for accept/reject ✅ Link to third-party privacy policies

Transparency Requirements

First-Party Cookie Disclosure:

Privacy policies must explain:

• What first-party cookies you set
• Purposes for each cookie type
• Retention periods
• How users can manage/delete cookies

Third-Party Cookie Disclosure:

Privacy policies must additionally include:

• Identity of each third-party service
• What data is shared with third parties
• Third parties' purposes for processing
• Links to third-party privacy policies
• Information about cross-site tracking
• Users' rights regarding third-party data

Practical Examples

First-Party Cookie Scenario

// example.com sets first-party authentication cookie
document.cookie = "user_session=abc123; Domain=.example.com; Secure; HttpOnly; SameSite=Strict";

// First-party analytics (cookieless or privacy-focused)
// Matomo self-hosted on example.com subdomain
analytics.example.com

GDPR Considerations:

• Session cookie: Strictly necessary, no consent required
• Analytics: Requires consent or valid legitimate interest assessment
• All data processing happens on example.com infrastructure
• User maintains control over their data

Third-Party Cookie Scenario

<!-- example.com loads Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=GA_MEASUREMENT_ID"></script>

<!-- Sets cookies from google.com domain -->
<!-- Cookies: _ga, _gid, _gat -->

<!-- Facebook Pixel -->
<script>
  !function(f,b,e,v,n,t,s)
  {/* Facebook tracking code */}
</script>
<!-- Sets cookies from facebook.com domain -->

GDPR Considerations:

• Google Analytics and Facebook Pixel are third-party services
• Cookies set from external domains
• Data shared with Google and Facebook
• Enables cross-site tracking
• Requires explicit opt-in consent before loading
• Must disclose data sharing in privacy policy

Privacy Risks: First-Party vs Third-Party

First-Party Cookie Risks (Lower)

Limited Tracking Scope:

• Data collection confined to single website
• No cross-site user profiling
• Direct relationship between user and website

Clearer Purpose:

• Users visit website intentionally
• Cookie purposes tied to website functionality
• More predictable data usage

Easier to Manage:

• Users can clear cookies per-site
• Browser tools provide visibility
• Direct relationship with data controller

Third-Party Cookie Risks (Higher)

Pervasive Tracking:

• Follow users across hundreds of websites
• Build comprehensive behavioral profiles
• Track browsing history and interests
• Identify users across devices

Opaque Data Processing:

• Users unaware of third-party presence
• Complex data sharing arrangements
• Data used for purposes beyond original site
• Potential data sales to additional parties

Limited User Control:

• Difficult to identify all third parties
• Unclear what data is collected
• Hard to exercise privacy rights across multiple controllers
• No direct relationship with third-party

Browser Evolution and Third-Party Cookie Deprecation

Industry Changes (2025)

Major browsers are phasing out third-party cookies:

Safari (Apple):

• Intelligent Tracking Prevention (ITP) since 2017
• Blocks most third-party cookies by default
• 24-hour cap on first-party cookies set via JavaScript

Firefox (Mozilla):

• Enhanced Tracking Protection (ETP) since 2019
• Blocks known trackers and third-party cookies
• Total Cookie Protection in strict mode

Chrome (Google):

• Third-party cookie deprecation delayed to 2025
• Privacy Sandbox as cookie alternative
• Gradual rollout to 100% of users

Impact on GDPR:

While browser-level blocking reduces third-party tracking, GDPR compliance still requires:

• Consent for any tracking that does occur
• Disclosure of all data processing
• Compliance with alternative tracking methods (fingerprinting, server-side tracking)
• Proper handling of first-party cookies set for third-party purposes

First-Party Cookies for Third-Party Purposes

The Gray Area

Some implementations use first-party cookies to serve third-party purposes:

Server-Side Tag Management:

// Appears as first-party request to example.com
// But data forwarded to Google Analytics server-side
POST https://example.com/analytics
// Backend forwards to Google Analytics

CNAME Cloaking:

// Third-party analytics disguised as subdomain
analytics.example.com → CNAME → external-analytics.com

GDPR Position:

These techniques do not bypass GDPR requirements:

• Purpose matters more than technical implementation
• Data sharing with third parties still requires consent
• Circumventing browser protections may violate user expectations
• Regulatory guidance treats these as third-party tracking
• Transparency requirements apply regardless of technical method

Compliance Best Practices

For First-Party Cookies

1. Categorize properly: Distinguish strictly necessary from non-essential
2. Minimize scope: Only set cookies actually needed
3. Clear purposes: Document why each cookie exists
4. Appropriate duration: Set shortest reasonable expiration
5. Secure attributes: Use Secure, HttpOnly, SameSite flags
6. Respect DNT: Consider Do Not Track signals
7. Consent for non-essential: Don't assume legitimate interest applies

For Third-Party Cookies

1. Explicit consent: Never load before user opt-in
2. Granular control: Allow per-service consent decisions
3. Clear disclosure: Name each third-party service
4. Privacy policy details: Comprehensive third-party section
5. Data processing agreements: Ensure contracts in place
6. Regular audits: Monitor what third parties are actually loading
7. Consider alternatives: Evaluate if third-party services are necessary

Cookie Consent Implementation

Recommended Approach:

// Only load third-party services after consent
function onConsentGranted(categories) {
  if (categories.includes('analytics')) {
    loadGoogleAnalytics();
  }
  if (categories.includes('marketing')) {
    loadFacebookPixel();
    loadGoogleAds();
  }
}

// Strictly necessary first-party cookies (no consent needed)
function setSessionCookie() {
  document.cookie = "session=xyz; Secure; HttpOnly; SameSite=Strict";
}

// Non-essential first-party cookies (require consent)
function onAnalyticsConsent() {
  document.cookie = "analytics_preference=enabled; Secure; SameSite=Lax";
}

Enforcement and Penalties

Recent Actions (2025)

Regulators increasingly target cookie consent violations:

Common Violations:

• Pre-loading third-party cookies before consent
• Bundling consent (forcing users to accept all or nothing)
• No reject option on first layer
• Hidden or unclear cookie information
• Continuing to track after consent withdrawal

Fine Examples:

• Google/Facebook: €90 million (French DPA) for non-compliant cookie consent
• Amazon: €746 million for tracking without valid legal basis
• Real-time bidding platforms: Multiple fines for third-party data sharing

Enforcement Priorities:

• Third-party tracking and advertising cookies
• Cross-border data transfers via cookies
• Lack of granular consent options
• Deceptive consent banner designs

Conclusion

First-party and third-party cookies differ fundamentally in origin, purpose, and privacy implications under GDPR:

First-Party Cookies:

• Set by the website you're visiting
• Typically serve site functionality and user preferences
• Lower privacy risk (single-site scope)
• Some categories exempt from consent (strictly necessary)
• Can rely on various legal bases depending on purpose

Third-Party Cookies:

• Set by external domains
• Enable cross-site tracking and behavioral profiling
• Higher privacy risk (pervasive tracking)
• Almost always require explicit opt-in consent
• Subject to stricter transparency requirements

In 2025, GDPR enforcement focuses heavily on cookie consent compliance, particularly for third-party tracking cookies. Organizations must implement proper consent management systems that:

• Distinguish between first-party and third-party cookies
• Categorize cookies by purpose and necessity
• Obtain granular, explicit consent before loading non-essential cookies
• Provide clear transparency about third-party data sharing
• Enable easy consent withdrawal

Our GDPR Checker tool helps identify first-party and third-party cookies on your website, assess consent implementation, and understand your compliance status with current GDPR requirements.