Nextdoor Ads

Overview

Nextdoor Ads is the advertising and conversion measurement platform for Nextdoor, the neighborhood-focused social network with over 40 million households across the US, UK, and other markets. Nextdoor's advertising proposition is built around local and hyperlocal targeting — ads are served to users in specific postal codes, neighborhoods, or radius-based geographic zones. Advertisers install Nextdoor's conversion pixel on their websites to measure campaign performance by matching website visitors back to Nextdoor ad exposures.

What This Script Does

The Nextdoor pixel script is loaded from ads.nextdoor.com or embedded as a 1×1 pixel tag. It fires on advertiser-configured pages to record conversion events.

Cookies Set by Nextdoor Ads:

• ndp_uid — persistent cross-site user identifier, third-party, set under nextdoor.com domain, typically 365 days; used to recognize Nextdoor members who visit the advertiser's website and match them back to ad impressions served within the Nextdoor app or website
• ndp_session — session-scoped attribution marker; groups pixel fires within a single session for deduplication of conversion events
• ndp_click_[campaignid] — click attribution cookie, 30 days; set when a user clicks a Nextdoor ad and lands on the advertiser's site; used to attribute downstream conversions to the originating ad click

Data Collected Per Pixel Fire:

• Conversion event type (page view, lead, purchase, sign-up — as configured by the advertiser)
• Page URL at time of conversion
• Optional conversion value (purchase amount) if configured
• User identifier from ndp_uid cookie or Nextdoor member identity signals if available
• IP address and user-agent for geographic and device attribution
• Email address hash (SHA-256) if the advertiser passes hashed_email parameter for enhanced matching

Matching Mechanism:

• Browser-based cookie matching: ndp_uid is compared against Nextdoor's logged-in user database to identify conversions by Nextdoor members
• Email hash matching: hashed emails passed by advertisers are compared against Nextdoor's member email database for cookieless attribution

IAB TCF Purposes: Purposes 1, 2, 4, 5, and 7 apply.

Nextdoor is a US company. EU data transfers rely on Standard Contractual Clauses. Nextdoor participates in the EU-US Data Privacy Framework.

Consent & Compliance

Nextdoor Ads scripts are classified as marketing technology. Under GDPR Article 6(1)(a) and Article 5(3) ePrivacy Directive, the persistent cross-site user identifier and click attribution cookies require explicit prior consent. The email hash matching mechanism — transmitting hashed PII to Nextdoor for identity resolution — constitutes processing of personal data requiring consent. Under CCPA/CPRA, the cross-site conversion tracking and identity matching against Nextdoor's member database constitute "sharing" of personal information for cross-context behavioral advertising under Cal. Civ. Code §1798.140(ah), triggering opt-out obligations.

Should You Block This Without Consent?

Yes. Nextdoor Ads scripts perform cross-site conversion tracking and identity matching for advertising measurement. They are not required for site functionality and must be blocked until marketing consent is provided.