| utm_source | Google Analytics | Identifies the referrer / platform (e.g. google, newsletter) |
| utm_medium | Google Analytics | Identifies marketing medium (e.g. cpc, email, social) |
| utm_campaign | Google Analytics | Identifies specific marketing campaign |
| utm_term | Google Analytics | Tracks paid search keywords |
| utm_content | Google Analytics | Differentiates ads or links in the same campaign |
| utm_id | Google Analytics | Campaign ID used in GA4 imports |
| utm_source_platform | Google Analytics | Platform directing traffic to Google Analytics |
| utm_creative_format | Google Analytics | Format of the ad creative |
| utm_marketing_tactic | Google Analytics | Targeting tactic used |
| utm_name | Google Analytics | Legacy campaign name tag |
| gclid | Google Ads | Google Click Identifier |
| gclsrc | Google Ads | Google Click Source tracking |
| dclid | Google Display | DoubleClick / Google Display click ID |
| gad_source | Google Ads | Google Ads traffic source tag |
| gbraid | Google Ads (iOS) | App-to-web measurement tracking identifier |
| wbraid | Google Ads (iOS) | Web-to-app measurement tracking identifier |
| _gl | Google Analytics | Google Cross-domain tracking measurement cookie |
| _ga | Google Analytics | Google Universal Analytics client ID |
| _gid | Google Analytics | Google Analytics session measurement tag |
| fbclid | Meta / Facebook | Facebook Click Identifier |
| fbadid | Meta / Facebook | Facebook Ad ID |
| fb_action_ids | Meta / Facebook | Facebook social graph action ID |
| fb_action_types | Meta / Facebook | Facebook social graph action type |
| fb_source | Meta / Facebook | Facebook navigation source |
| fb_ref | Meta / Facebook | Facebook referral marker |
| igshid | Instagram | Instagram share tracking identifier |
| igsh | Instagram | Instagram shortened share hash |
| twclid | Twitter / X | Twitter Click Identifier |
| ref_src | Twitter / X | Twitter referral source |
| ref_url | Twitter / X | Twitter embed referral URL |
| ttclid | TikTok | TikTok Click Identifier |
| tt_medium | TikTok | TikTok Ads media channel |
| tt_content | TikTok | TikTok Ads creative content identifier |
| msclkid | Microsoft Advertising | Bing / Microsoft Ads Click Identifier |
| cvid | Microsoft Bing | Bing search correlation vector ID |
| li_fat_id | LinkedIn | LinkedIn First-party Ad Tracking ID |
| trk | LinkedIn | LinkedIn tracking parameter |
| trkInfo | LinkedIn | LinkedIn internal tracking metadata |
| midToken | LinkedIn | LinkedIn message tracking token |
| fromEmail | LinkedIn | Email tracking referral |
| mc_cid | Mailchimp | Mailchimp campaign ID |
| mc_eid | Mailchimp | Mailchimp subscriber email ID |
| mkt_tok | Marketo | Marketo email lead tracking token |
| _hsenc | HubSpot | HubSpot email encrypted tracking hash |
| _hsmi | HubSpot | HubSpot email marketing message ID |
| hsCtsTracking | HubSpot | HubSpot call-to-action click tracking |
| vero_id | Vero Email | Vero customer ID tracker |
| vero_conv | Vero Email | Vero conversion tracking tag |
| ml_subscriber | MailerLite | MailerLite subscriber ID |
| ml_subscriber_hash | MailerLite | MailerLite email verification hash |
| aff_id | Affiliate Network | Affiliate partner identifier |
| aff_sub | Affiliate Network | Affiliate custom sub-tracking parameter |
| aff_sub2 | Affiliate Network | Affiliate sub-ID 2 |
| aff_sub3 | Affiliate Network | Affiliate sub-ID 3 |
| click_id | Affiliate Network | Affiliate conversion click ID |
| clickid | Affiliate Network | Universal click tracking identifier |
| irclickid | Impact Radius | Impact affiliate click identifier |
| irgwc | Impact Radius | Impact Radius campaign attribution |
| zanpid | Awin / Zanox | Zanox affiliate tracking parameter |
| subid | Affiliate Network | Affiliate sub-account identifier |
| sub_id | Affiliate Network | Affiliate sub-account identifier |
| ranMID | Rakuten Marketing | Rakuten merchant ID |
| ranEAID | Rakuten Marketing | Rakuten encrypted affiliate ID |
| ranSiteID | Rakuten Marketing | Rakuten site attribution |
| si | YouTube | YouTube Share Tracking Identifier |
| feature | YouTube | YouTube referral feature parameter |
| app | YouTube / Google | Application launch telemetry |
| yclid | Yandex Direct | Yandex Click Identifier |
| ym_debug | Yandex Metrica | Yandex Metrica debugger parameter |
| ysclid | Yandex Search | Yandex search click tag |
| _openstat | Openstat / Yandex | Russian advertising campaign analytics tag |
| rdt_cid | Reddit Ads | Reddit Ads Click Identifier |
| epik | Pinterest | Pinterest click identifier |
| s_kwcid | Adobe Omniture | Adobe Marketing Cloud keyword campaign ID |
| s_iid | Adobe Omniture | Adobe internal link tracking ID |
| phpsessid | Session Tracker | PHP session ID leaked in URL |
| jsessionid | Session Tracker | Java EE session ID leaked in URL |
| aspsessionid | Session Tracker | ASP session ID leaked in URL |
| sid | Session Tracker | Generic session identifier |
| session_id | Session Tracker | Generic session identifier |
| zenid | Session Tracker | Zen Cart session identifier |
| _ga_* | Google Analytics 4 | GA4 measurement cookie container |