{"version":"2026-10-04","scope":"A curated list, not a complete one. It will miss regional ad networks, and it will not guess about parameters that are functional on some sites.","tracking":[{"param":"gclid","origin":"Google Ads","class":"click","note":"Auto-tagged onto every ad click.","doc":"https://support.google.com/google-ads/answer/6305348"},{"param":"gclsrc","origin":"Google Ads","class":"click","note":"Names the click source (aw.ds, 3p.ds)."},{"param":"gbraid","origin":"Google Ads","class":"click","note":"iOS web-to-app click cohort, added after Apple's tracking prompt (ATT).","doc":"https://support.google.com/google-ads/answer/16297842"},{"param":"wbraid","origin":"Google Ads","class":"click","note":"iOS app-to-web click cohort.","doc":"https://support.google.com/google-ads/answer/10417364"},{"param":"dclid","origin":"Campaign Manager 360","class":"click","note":"Display click ID."},{"param":"srsltid","origin":"Google Merchant Center","class":"click","note":"Attached to free product listings in search."},{"param":"gad_source","origin":"Google Ads","class":"click","note":"Click surface, added 2023."},{"param":"gad_campaignid","origin":"Google Ads","class":"session","note":"Campaign ID, added 2024."},{"param":"_gl","origin":"Google Analytics 4","class":"person","note":"The cross-domain linker: Google's own docs say the cookies' client ID and session ID are passed between domains in this parameter.","doc":"https://support.google.com/analytics/answer/10071811"},{"param":"_ga","origin":"Google Analytics","class":"person","note":"Legacy linker form of the client ID."},{"param":"ga_","prefix":true,"origin":"Google Analytics for email","class":"session","note":"Legacy campaign family."},{"param":"gs_l","origin":"Google Search","class":"session","note":"Result-position log from the search page."},{"param":"fbclid","origin":"Meta","class":"click","note":"Becomes the fbc identifier server-side, so it outlives the click."},{"param":"fb_action_ids","origin":"Facebook","class":"session"},{"param":"fb_action_types","origin":"Facebook","class":"session"},{"param":"fb_source","origin":"Facebook","class":"session","note":"Which Facebook surface the link was clicked from."},{"param":"fb_ref","origin":"Facebook","class":"session"},{"param":"action_object_map","origin":"Facebook Open Graph","class":"session"},{"param":"action_type_map","origin":"Facebook Open Graph","class":"session"},{"param":"action_ref_map","origin":"Facebook Open Graph","class":"session"},{"param":"mibextid","origin":"Meta","class":"session","note":"Added by the mobile share sheet."},{"param":"__tn__","hosts":["facebook.com"],"origin":"Facebook","class":"session","note":"Internal surface code."},{"param":"__cft__","prefix":true,"hosts":["facebook.com"],"origin":"Facebook","class":"session","note":"Click-tracking blob; the real key is __cft__[0]."},{"param":"__xts__","prefix":true,"hosts":["facebook.com"],"origin":"Facebook","class":"session","note":"Click-tracking blob; the real key is __xts__[0]."},{"param":"msclkid","origin":"Microsoft Advertising","class":"click","note":"A 32-character GUID, unique per click, auto-tagged on by default.","doc":"https://learn.microsoft.com/en-us/advertising/msa-help/hlp_ba_proc_microsoftclickid"},{"param":"ttclid","origin":"TikTok Ads","class":"click","note":"TikTok tells advertisers to store it 28 days or more and replay it to the Events API.","doc":"https://ads.tiktok.com/help/article/tiktok-click-id"},{"param":"tt_medium","origin":"TikTok","class":"session"},{"param":"tt_content","origin":"TikTok","class":"session"},{"param":"share_app_name","hosts":["tiktok.com"],"origin":"TikTok","class":"session"},{"param":"share_iid","hosts":["tiktok.com"],"origin":"TikTok","class":"session"},{"param":"u_code","hosts":["tiktok.com"],"origin":"TikTok","class":"session"},{"param":"twclid","origin":"X Ads","class":"click"},{"param":"__twitter_impression","origin":"X","class":"session"},{"param":"s","hosts":["x.com","twitter.com"],"origin":"X share sheet","class":"session","note":"Names the surface the link was shared from (s=20, s=46)."},{"param":"t","hosts":["x.com","twitter.com"],"origin":"X share sheet","class":"session","note":"Opaque share token. On YouTube the same name is a timestamp and is never removed."},{"param":"ref_src","hosts":["x.com","twitter.com"],"origin":"X embeds","class":"session"},{"param":"ref_url","hosts":["x.com","twitter.com"],"origin":"X embeds","class":"session","note":"Carries the referring page's own URL."},{"param":"yclid","origin":"Yandex.Direct","class":"click"},{"param":"_openstat","origin":"Openstat","class":"session","note":"Base64 of four campaign fields."},{"param":"mc_cid","origin":"Mailchimp","class":"session","note":"The Mailchimp ID for the campaign that generated the link.","doc":"https://mailchimp.com/developer/marketing/docs/e-commerce/"},{"param":"mc_eid","origin":"Mailchimp","class":"person","note":"Your subscriber ID in the sender's Mailchimp list.","doc":"https://mailchimp.com/developer/marketing/docs/e-commerce/"},{"param":"mc_tc","origin":"Mailchimp","class":"session"},{"param":"__hstc","origin":"HubSpot","class":"person","note":"HubSpot's main visitor cookie, carrying hubspotutk.","doc":"https://knowledge.hubspot.com/reports/what-cookies-does-hubspot-set-in-a-visitor-s-browser"},{"param":"__hssc","origin":"HubSpot","class":"session","doc":"https://knowledge.hubspot.com/reports/what-cookies-does-hubspot-set-in-a-visitor-s-browser"},{"param":"__hsfp","origin":"HubSpot","class":"person","note":"Device fingerprint."},{"param":"_hsenc","origin":"HubSpot email","class":"person","note":"Encoded recipient token."},{"param":"_hsmi","origin":"HubSpot email","class":"session","note":"Message ID."},{"param":"hsctatracking","origin":"HubSpot CTA","class":"session","note":"CTA GUID pair."},{"param":"mkt_tok","origin":"Marketo","class":"person","note":"Base64 blob carrying the lead ID and the send ID."},{"param":"_kx","origin":"Klaviyo","class":"person","note":"Klaviyo's own docs: an encrypted value decrypted by their web tracking to identify the user who clicked.","doc":"https://help.klaviyo.com/hc/en-us/articles/360034666712"},{"param":"s_cid","origin":"Adobe Campaign","class":"session"},{"param":"s_kwcid","origin":"Adobe Advertising","class":"click","note":"Keyword ID."},{"param":"ef_id","origin":"Adobe Advertising Cloud","class":"click"},{"param":"vero_conv","origin":"Vero","class":"session"},{"param":"vero_id","origin":"Vero","class":"person"},{"param":"bsft_","prefix":true,"origin":"Blueshift","class":"person","note":"Blueshift's email click family."},{"param":"utm_","prefix":true,"origin":"Google Analytics, and by now everyone","class":"session","note":"The campaign family: source, medium, campaign, term, content, id, source_platform, creative_format, marketing_tactic.","doc":"https://matomo.org/faq/reports/how-to-build-campaign-tracking-urls/"},{"param":"mtm_","prefix":true,"origin":"Matomo 4+","class":"session","note":"Matomo's eight documented campaign parameters.","doc":"https://matomo.org/faq/how-to/faq_120/"},{"param":"pk_","prefix":true,"origin":"Piwik / Matomo 3","class":"session","note":"Kept working for backwards compatibility.","doc":"https://matomo.org/faq/how-to/faq_120/"},{"param":"piwik_","prefix":true,"origin":"Piwik","class":"session"},{"param":"matomo_","prefix":true,"origin":"Matomo","class":"session"},{"param":"igshid","origin":"Instagram","class":"session","note":"Share ID, added to links shared out of the app."},{"param":"igsh","origin":"Instagram","class":"session","note":"Share ID, newer form."},{"param":"si","hosts":["youtube.com","youtu.be"],"origin":"YouTube","class":"session","note":"Share-attribution token. Not removed on Spotify: there it is reported to gate access on playlist invites."},{"param":"feature","hosts":["youtube.com","youtu.be"],"origin":"YouTube","class":"session"},{"param":"kw","hosts":["youtube.com"],"origin":"YouTube","class":"session"},{"param":"pp","hosts":["youtube.com","youtu.be"],"origin":"YouTube","class":"session"},{"param":"ref","hosts":["amazon."],"origin":"Amazon","class":"session","note":"Placement breadcrumb. Scoped to Amazon: on a git forge the same name picks a branch."},{"param":"ref_","prefix":true,"hosts":["amazon."],"origin":"Amazon","class":"session"},{"param":"pd_rd_","prefix":true,"hosts":["amazon."],"origin":"Amazon","class":"session","note":"Recommendation slot."},{"param":"pf_rd_","prefix":true,"hosts":["amazon."],"origin":"Amazon","class":"session","note":"Recommendation slot."},{"param":"qid","hosts":["amazon."],"origin":"Amazon","class":"session","note":"Search-result context."},{"param":"crid","hosts":["amazon."],"origin":"Amazon","class":"session","note":"Search-result context."},{"param":"sprefix","hosts":["amazon."],"origin":"Amazon","class":"session","note":"What was typed before the search ran."},{"param":"tag","hosts":["amazon."],"origin":"Amazon Associates","class":"affiliate","note":"Removing it takes their commission."},{"param":"linkcode","hosts":["amazon."],"origin":"Amazon Associates","class":"affiliate"},{"param":"ascsubtag","hosts":["amazon."],"origin":"Amazon Associates","class":"affiliate","note":"Publisher's own sub-tag; often identifies the article."},{"param":"creativeasin","hosts":["amazon."],"origin":"Amazon Associates","class":"affiliate"},{"param":"trk","hosts":["linkedin.com"],"origin":"LinkedIn","class":"session","note":"Traffic-source code."},{"param":"trkinfo","hosts":["linkedin.com"],"origin":"LinkedIn","class":"session"},{"param":"trackingid","hosts":["linkedin.com"],"origin":"LinkedIn","class":"session"},{"param":"lipi","hosts":["linkedin.com"],"origin":"LinkedIn","class":"person","note":"Page-instance ID, joinable to the viewing member."},{"param":"licu","hosts":["linkedin.com"],"origin":"LinkedIn","class":"person"},{"param":"li_fat_id","hosts":["linkedin.com"],"origin":"LinkedIn Ads","class":"click"},{"param":"share_id","hosts":["reddit.com"],"origin":"Reddit","class":"session"},{"param":"ref_campaign","hosts":["reddit.com"],"origin":"Reddit","class":"session"},{"param":"ref_source","hosts":["reddit.com"],"origin":"Reddit","class":"session"},{"param":"rdt","hosts":["reddit.com"],"origin":"Reddit","class":"session"},{"param":"_branch_match_id","hosts":["reddit.com"],"origin":"Branch (via Reddit)","class":"session","note":"Deep-link match ID."},{"param":"spm","hosts":["aliexpress.","taobao.com","tmall.com","lazada."],"origin":"Alibaba","class":"session","note":"Placement path through the site."},{"param":"algo_pvid","hosts":["aliexpress."],"origin":"AliExpress","class":"session","note":"Experiment arm."},{"param":"ws_ab_test","hosts":["aliexpress."],"origin":"AliExpress","class":"session","note":"Experiment arm."},{"param":"r","hosts":["substack.com"],"origin":"Substack","class":"person","note":"The referring subscriber. Custom Substack domains are unreachable from the name alone, so this only fires on substack.com."},{"param":"triedredirect","hosts":["substack.com"],"origin":"Substack","class":"session"},{"param":"showwelcomeonshare","hosts":["substack.com"],"origin":"Substack","class":"session"}],"never_strip":[{"param":"q","why":"The search is gone. On google.com/url?q= it is the destination itself, so deleting it turns an unwrap into a dead link."},{"param":"id","why":"Wrong record, or a 404. Every CMS and REST route in existence uses this name."},{"param":"uid","why":"Wrong record, or a 404."},{"param":"pid","why":"Wrong record, or a 404."},{"param":"item","why":"Wrong record, or a 404."},{"param":"sku","why":"Wrong product."},{"param":"page","why":"Silently resets to page 1; the reader assumes the link was wrong."},{"param":"p","why":"Pagination on countless sites, and a catch-all elsewhere. Too broad to guess at."},{"param":"offset","why":"Pagination resets."},{"param":"limit","why":"Page size resets; a deep link into a long list stops working."},{"param":"cursor","why":"Cursor pagination restarts from the beginning."},{"param":"after","why":"Cursor pagination restarts from the beginning."},{"param":"token","why":"The link is dead. Password resets, magic links and email confirmations are usually single-use, so retrying does not recover it."},{"param":"code","why":"OAuth 2.0 authorization response (RFC 6749 §4.1.2). The token exchange never happens and login loops back to the start."},{"param":"state","why":"OAuth 2.0 CSRF binding (RFC 6749 §10.12). The client cannot bind the callback to its request and fails closed, with an incomprehensible error."},{"param":"redirect_uri","why":"OAuth 2.0 authorization request (RFC 6749 §3.1.2). invalid_request, or a silent fall-back to a registered default that is not where the user was going."},{"param":"nonce","why":"OpenID Connect ID-token validation fails."},{"param":"session","why":"Logged out."},{"param":"sid","why":"Removing it logs you out."},{"param":"sessionid","why":"Logged out."},{"param":"jsessionid","why":"Logged out."},{"param":"phpsessid","why":"Logged out."},{"param":"s_id","why":"Logged out."},{"param":"sig","why":"Signature mismatch, 403. Also an Azure SAS field."},{"param":"signature","why":"Signature mismatch, 403."},{"param":"hmac","why":"Signature mismatch, 403."},{"param":"mac","why":"Signature mismatch, 403."},{"param":"x-amz-","prefix":true,"why":"403 SignatureDoesNotMatch on an S3 presigned URL."},{"param":"x-goog-","prefix":true,"why":"403 on a Google Cloud Storage signed URL."},{"param":"awsaccesskeyid","why":"403 on an S3 SigV2 presigned URL."},{"param":"expires","why":"403 on a SigV2 presigned URL, and a cache directive elsewhere."},{"param":"key-pair-id","why":"403 on a CloudFront signed URL."},{"param":"policy","why":"403 on a CloudFront signed URL."},{"param":"sv","hosts":["core.windows.net"],"why":"403 on an Azure Blob SAS URL."},{"param":"se","hosts":["core.windows.net"],"why":"403 on an Azure Blob SAS URL."},{"param":"sp","hosts":["core.windows.net"],"why":"403 on an Azure Blob SAS URL. Note sp is also a Bing tracking parameter."},{"param":"st","hosts":["core.windows.net"],"why":"403 on an Azure Blob SAS URL."},{"param":"sr","hosts":["core.windows.net"],"why":"403 on an Azure Blob SAS URL."},{"param":"v","hosts":["youtube.com"],"why":"?v= is the video ID. Remove it and the URL is the YouTube homepage."},{"param":"t","hosts":["youtube.com","youtu.be"],"why":"The timestamp: ?t=90 is a deep link into the middle of the video. The same name on x.com is a share token, and is removed there."},{"param":"start","hosts":["youtube.com","youtu.be"],"why":"The timestamp for an embed."},{"param":"si","hosts":["spotify.com"],"why":"Reported to gate access on collaborative and private playlist invites: the recipient gets a permission error instead of the playlist. Reported, not confirmed."},{"param":"u","hosts":["list-manage.com"],"why":"The unsubscribe link silently stops working."},{"param":"e","hosts":["list-manage.com"],"why":"The unsubscribe silently does nothing."},{"param":"c","hosts":["list-manage.com"],"why":"The unsubscribe silently does nothing."},{"param":"hash","hosts":["list-manage.com"],"why":"The unsubscribe silently does nothing."},{"param":"ref","hosts":["github.com","gitlab.com","codeberg.org","bitbucket.org","gitea.com","git.sr.ht"],"why":"?ref=main picks a branch: without it, the wrong branch, or a 404."},{"param":"format","why":"Wrong content type."},{"param":"output","why":"Wrong content type."},{"param":"callback","why":"A JSONP call that never invokes its callback."},{"param":"jsonp","why":"A JSONP call that never invokes its callback."},{"param":"alt","why":"Wrong response format on Google APIs."},{"param":"lang","why":"Wrong language."},{"param":"hl","why":"Wrong language."},{"param":"locale","why":"Wrong language."},{"param":"gl","why":"Wrong region. One underscore from _gl, which is removed."},{"param":"cid","why":"Adobe's conventional campaign slot, and also customer ID, conversation ID and channel ID on countless apps. The ambiguous case that most looks safe and is not."},{"param":"icid","why":"Same ambiguity as cid."},{"param":"int_cid","why":"Same ambiguity as cid."},{"param":"variant","why":"Wrong Shopify product variant, wrong price."},{"param":"share","why":"Changes content disposition on some hosts."},{"param":"dl","why":"Renders instead of downloading."},{"param":"download","why":"Renders instead of downloading."},{"param":"raw","why":"Renders instead of serving the file."}],"wrappers":[{"name":"Microsoft Safe Links","hosts":["*.safelinks.protection.outlook.com","*.safelinks.protection.office365.us","*.safelinks.protection.outlook.cn"],"shape":"param","params":["url"],"confidence":"high","doc":"https://learn.microsoft.com/en-us/defender-office-365/safe-links-about"},{"name":"Proofpoint urldefense v1","hosts":["urldefense.proofpoint.com","urldefense.com"],"path":"/v1/url","shape":"custom","confidence":"high"},{"name":"Proofpoint urldefense v2","hosts":["urldefense.proofpoint.com","urldefense.com"],"path":"/v2/url","shape":"custom","confidence":"high"},{"name":"Proofpoint urldefense v3","hosts":["urldefense.com","urldefense.proofpoint.com"],"path":"/v3/","shape":"custom","confidence":"high"},{"name":"Google redirect","hosts":["google."],"path":"/url","shape":"param","params":["q","url"],"confidence":"high"},{"name":"Google AMP viewer","hosts":["google."],"path":"/amp/","shape":"custom","confidence":"medium"},{"name":"Google Ads redirect","hosts":["google.","googleadservices.com"],"shape":"param","params":["adurl"],"confidence":"medium"},{"name":"Meta link shim","hosts":["l.facebook.com","lm.facebook.com","l.messenger.com"],"shape":"param","params":["u"],"confidence":"high","doc":"https://engineering.fb.com/2012/09/14/security/a-faster-better-link-shim/"},{"name":"Instagram link shim","hosts":["l.instagram.com"],"shape":"param","params":["u"],"confidence":"medium"},{"name":"YouTube redirect","hosts":["youtube.com"],"path":"/redirect","shape":"param","params":["q"],"confidence":"high"},{"name":"Cisco Secure Email","hosts":["secure-web.cisco.com"],"shape":"path-tail","confidence":"high"},{"name":"Barracuda Link Protect","hosts":["linkprotect.cudasvc.com"],"path":"/url","shape":"param","params":["a"],"confidence":"high"},{"name":"Mimecast URL Protect","hosts":["mimecast.com"],"path":"/s/","shape":"param","params":["domain"],"partial":true,"confidence":"medium","doc":"https://mimecastsupport.zendesk.com/hc/en-us/articles/34000769379219-Targeted-Threat-Protection-URL-Protect-Embedded-Links"},{"name":"Tumblr redirect","hosts":["t.umblr.com"],"path":"/redirect","shape":"param","params":["z"],"confidence":"high"},{"name":"Reddit outbound","hosts":["out.reddit.com","click.redditmail.com"],"shape":"param","params":["url"],"confidence":"high"},{"name":"Steam link filter","hosts":["steamcommunity.com"],"path":"/linkfilter","shape":"param","params":["url","u"],"confidence":"medium"},{"name":"VK away","hosts":["vk.com"],"path":"/away.php","shape":"param","params":["to"],"confidence":"high"},{"name":"LinkedIn interstitial","hosts":["linkedin.com"],"path":"/redir/redirect","shape":"param","params":["url"],"confidence":"medium"},{"name":"Slack redirect","hosts":["slack-redir.net"],"path":"/link","shape":"param","params":["url"],"confidence":"medium"},{"name":"href.li","hosts":["href.li"],"shape":"bare-query","confidence":"high"},{"name":"DeviantArt outgoing","hosts":["deviantart.com"],"path":"/users/outgoing","shape":"bare-query","confidence":"high"}]}