Floodlight is the conversion tracking system built into Campaign Manager 360 (CM360), the advertiser ad server inside Google Marketing Platform (GMP). An advertiser places Floodlight tags on the pages where valuable things happen - a basket, a sign-up, a purchase confirmation - and each time one fires, CM360 records a conversion and tries to link it to an earlier ad impression or click. It exists because large advertisers buy through several tools at once - Display & Video 360 (DV360) for programmatic media, Search Ads 360 (SA360) for paid search, CM360 for ads bought elsewhere - and without one shared counter each would claim the same sale. Floodlight is that shared counter: one tag, one set of rules, one conversion credited to one ad.

How a Floodlight tag works

The structure has three layers. At the top sits the Floodlight configuration, which belongs to one CM360 advertiser and holds the settings that apply to every tag beneath it: lookback windows, custom variables, cookie behaviour and which other advertisers may share it. Its numeric identifier appears in every tag as the src value. Beneath it are activity groups, identified in tags by a type string, which bundle related actions for reporting. At the bottom are activities, identified by a cat string.

Each activity is one of two tag types. Counter tags count events, such as page views or form submissions. Sales tags also carry revenue, quantity and an order identifier. Counting methods sit on top of the type. A counter can count every firing (Standard, now labelled "Every"), the first conversion for each user during each 24-hour day (Unique, now "One per user"), or one per user per session (Per session). A sales tag can count each order (Transactions) or each item in the basket (Items sold). The choice changes the numbers sharply: a newsletter page loaded five times by one person is five Standard conversions and one Unique conversion.

The tag itself has taken three forms. The original image tag is a 1x1 pixel request to ad.doubleclick.net/activity carrying src, type and cat, plus an ord value. On Standard counters ord is a random number generated on each page load; Unique counters set it to 1 and move the random number to num; Per session counters pass a session ID. On sales tags ord holds the order ID, and qty and cost carry quantity and revenue. If ord is not unique, Google says, only the first conversion per user per day is recorded. An iframe tag wraps the same request in a frame so that other pixels can be loaded inside it. Since the late 2010s Google has steered advertisers to the Google tag (gtag.js, formerly the global site tag), in which a Floodlight event is addressed as DC-[configuration ID]/[group]/[activity]+[counting method].

Custom data travels in Floodlight variables, named u1 upward, which can carry product category, membership status or a lead score; Google allows up to 100 per configuration. Tags also carry privacy flags: npa to keep a conversion out of remarketing, tag_for_child_directed_treatment for the US children's privacy law COPPA, tfua for users under the age of consent, and dc_lat and dc_rdid for mobile limit-ad-tracking and device IDs.

Attribution and de-duplication

When a tag fires, CM360 looks back for a qualifying ad event from the same user. Clicks and impressions are logged by CM360 when it serves an ad or when a click tracker or impression tracker sits on media bought elsewhere. DV360 and SA360 log their own events against the same configuration. The lookback window, set on the configuration and adjustable per activity, decides how far back CM360 searches; Google's default is 30 days for clicks and impressions.

Credit then follows a hierarchy. A click beats an impression, and the most recent click wins, so a conversion is usually reported as click-through or, where only an impression preceded it, view-through. Because every channel reports into the same configuration, a sale preceded by a paid search click and a display impression is counted once and credited to the search click. That de-duplication is the main reason advertisers keep Floodlight even when each platform has its own tag. CM360's Path to Conversion report, which requires a Floodlight configuration ID, shows the full sequence, with up to 100 clicks and 100 impressions over as long as 90 days.

Matching originally relied on DoubleClick's third-party cookie on doubleclick.net. Floodlight now leans on first-party cookies set through the Google tag and on the dclid click identifier appended to landing page URLs. Where neither is available, Google fills gaps with modeled conversions. DV360 and CM360 report modeled Floodlight conversions.

Who runs it

On the buy side the tag is usually owned by the advertiser or its agency's ad operations team, which creates configurations in CM360 and supplies tags to the advertiser's developers or tag manager. DV360 traders select Floodlight activities as goals for automated bidding such as target cost per acquisition (CPA), and DV360's custom bidding can score impressions using Floodlight variables. SA360 depends on Floodlight more directly: each SA360 sub-manager must exist as an advertiser in CM360, according to Google's help centre, because SA360 uses Floodlight as its conversion source.

Origin and evolution

Floodlight is older than Google's ownership of it. It was the conversion tagging system of DoubleClick's DART for Advertisers (DFA), the ad server Google acquired when it completed the $3.1bn DoubleClick purchase on March 11, 2008.

Google rebuilt it in stages. On March 13, 2012, DoubleClick Search, the predecessor of SA360, announced Floodlight management inside its own interface, so search teams no longer needed DFA access to create tags.

Privacy changes then forced deeper rework. Apple's Intelligent Tracking Prevention, introduced in Safari in September 2017, cut the life of third-party cookies and later of some first-party ones. Floodlight's move to first-party cookies through the Google tag was Google's main response. When DoubleClick's brand was retired on June 27, 2018, DoubleClick Campaign Manager became Campaign Manager, later Campaign Manager 360, and Floodlight kept its name. Consent mode, extended to version 2 in November 2023 with enforcement in the European Economic Area (EEA) from March 2024, changed how Floodlight behaves when users decline cookies: tags send cookieless pings that feed modeling rather than identified hits.

Why it matters for marketers

For advertisers buying through GMP, Floodlight is the currency. Bidding algorithms in DV360 and SA360 learn from it, so a misconfigured counting method or a missing variable distorts spend as well as reporting. It is also the bridge between Google's enterprise tools and the rest of its stack. In June 2024 Google Analytics 4 began sending conversions to Floodlight configurations through Floodlight linking, making GA4 conversions available to DV360 and SA360 advertisers. In August 2024 SA360 added Microsoft's automated bidding to its strategies, fed by shared Floodlight data.

Data entry has widened beyond the tag. Version 1.7 of Google's Data Manager API, dated May 28, 2026, added offline conversion uploads for CM360, SA360 and DV360, with a Floodlight configuration destination type and a field for the dclid. A call centre can now report a sale against the same activity as a website.

Limitations and disputes

Discrepancies are the most common complaint. Floodlight counts rarely match an advertiser's own order system or GA4, and Google's help centre lists reasons including users who reject cookies or device IDs, different counting methods and conversion windows, time zones, last-click rules, discarded clicks and spam filtering, and differences between CM360 and SA360 reports.

Self-attribution is the structural criticism. Floodlight is Google's measurement of media bought largely through Google, and its default last-event logic gives every Google-served touchpoint a chance at credit. View-through conversions are the sharpest point of contention, since an impression that was served but perhaps never seen can claim a sale within 30 days. DV360 offers last-click, first-click and data-driven models, but the data-driven option is Google's own model, trained on Google's data.

Signal loss keeps eroding coverage. Browser restrictions, ad blockers, consent refusals and cross-device journeys all break the link between ad and conversion, and the gap is increasingly filled by modeling that advertisers cannot audit line by line. Tag hygiene is a practical limit, and CM360's implementation alerts exist largely to catch broken or silent tags.

Floodlight and adjacent terms

  • Google Ads conversion tag. Google Ads uses its own conversion actions, addressed as AW- IDs in the Google tag. Floodlight activities use DC- IDs and live in CM360. SA360 can report both.
  • GA4 key events. Analytics events measure site behaviour from all traffic sources. Floodlight measures conversions for ad attribution. Floodlight linking passes one into the other but they remain separate systems.
  • DCLID and GCLID. The dclid is the click identifier used by CM360 and DV360 for Floodlight. The gclid is the Google Ads click identifier. Both can appear on one URL.
  • Campaign Manager 360. CM360 is the ad server and reporting tool; Floodlight is one component inside it.

Recent developments

Google has spent 2026 moving Floodlight closer to its signed-in data. PPC Land reported on October 16 that, from November 2026, Floodlight would begin using Google signed-in data to recover unattributed conversions across devices in DV360, SA360 and CM360 reporting. Server-side tagging changes are next: from January 11, 2027, Google ad tags gain full IP addresses unless server-side Google Tag Manager owners intervene. On the administrative side, Google has said the Google tag page in its GMP products is moving to Data Manager, and agency New Age reported Floodlight reports migrating to CM360's Instant Reporting in June 2026.

Timeline

  • Before 2008 - Floodlight operates as the conversion tag in DoubleClick's DART for Advertisers.
  • March 11, 2008 - Google completes its $3.1bn acquisition of DoubleClick.
  • March 13, 2012 - DoubleClick Search adds Floodlight management.
  • September 2017 - Safari introduces Intelligent Tracking Prevention.
  • June 27, 2018 - DoubleClick brand retired; DoubleClick Campaign Manager becomes Campaign Manager under Google Marketing Platform.
  • November 2023 - Consent mode v2 parameters introduced; EEA enforcement follows in March 2024.
  • June 2024 - GA4 Floodlight linking connects GA4 properties to CM360 Floodlight configurations.
  • August 2024 - SA360 adds Microsoft automated bidding using Floodlight data.
  • May 28, 2026 - Data Manager API v1.7 adds offline conversions for CM360, SA360 and DV360.
  • June 2026 - Floodlight reports move to Instant Reporting, according to New Age.
  • November 2026 - Floodlight starts using Google signed-in data for cross-device conversions.
  • January 11, 2027 - Google ad tags to receive full IP addresses via server-side tagging.

Summary

Who: Google operates Floodlight inside Campaign Manager 360. Advertisers and agency ad operations teams configure it; DV360 and SA360 bid and report on it.

What: A conversion tracking system of configurations, activity groups and activities, using counter and sales tags, that credits each conversion to one prior click or impression across Google's enterprise tools.

When: Inherited from DoubleClick, which Google bought in 2008, and reworked through the 2010s and 2020s for first-party cookies, consent mode, offline uploads (May 2026) and signed-in data (November 2026).

Where: On advertiser websites and apps, via image, iframe or Google tag implementations, with data flowing into CM360, DV360, SA360 and, through linking, GA4.

Why: To give advertisers buying through several Google tools a single, de-duplicated conversion count, at the cost of relying on Google to measure media largely bought through Google.