This article is semi-technical (the iOS change is technical) but also veers into how it would impact various “individual” tracking providers who rely on ID’s transmitted via URL for tracking. It is a set of multiple articles
Article One: What is the Change
The iOS26 is being operated on Apple (Software) code base and anything that starts within Apple controlled code based like;
- In-App Browser (WebKit OS)
- Native Email
- Native SMS
- Safari [ iOS and Desktop ]
iOS26 changes by default [ not just private browsing like in iOS17 ];
- Removes individual (not all) Click IDs from URLs [ see list below ]
- No UTM impact
- No Analytics ID impact [ mostly but for a couple ]
- No Custom ID impact [ very with method used ]
Impact Overview
| Jumping from | Jumping to | Notes |
|---|---|---|
| Apple Mail/SMS | Non Safari | Not Impacted |
| Any | Safari (desktop and mobile) | Impacted |
| Chrome | Chrome | Not Impacted |
| Other Browsers | Other Browsers | Not Impacted |
| In-App Browser (Meta, IG, Google, etc) | Safari | Impacted |
| In-App Browser (Meta, IG, Google, etc) | Other Browsers | Not Impacted |
What IDs are impacted (today)?
Here is the current list [ Sept 4, 2025 ]
| Click ID | Platform Name | Category |
|---|---|---|
| __hsfp | HubSpot | Marketing Automation/CRM |
| __hssc | HubSpot | Marketing Automation/CRM |
| __hstc | HubSpot | Marketing Automation/CRM |
| __s | HubSpot | Marketing Automation/CRM |
| _hsenc | HubSpot | Marketing Automation/CRM |
| hsCtaTracking | HubSpot | Marketing Automation/CRM |
| dclid | DoubleClick | Advertising/Display |
| gclid | Google Ads | Advertising/Search |
| fbclid | Social Media | |
| igshid | Social Media | |
| msclkid | Microsoft/Bing Ads | Advertising/Search |
| twclid | Social Media | |
| yclid | Yandex | Search Engine |
| mc_eid | Mailchimp | Email Marketing |
| mkt_tok | Marketo | Marketing Automation |
| ml_subscriber | MailerLite | Email Marketing |
| ml_subscriber_hash | MailerLite | Email Marketing |
| vero_conv | Vero | Email Marketing |
| vero_id | Vero | Email Marketing |
| rb_clickid | Rakuten Advertising | Affiliate Marketing |
| s_cid | Adobe Analytics | Analytics |
| oly_anon_id | Olytics | Analytics |
| oly_enc_id | Olytics | Analytics |
| wickedid | Wicked Reports | Analytics/Attribution |
| _openstat | OpenStat | Analytics |
We came up with the list by actually doing our own testing; for austerity reasons and IP we are not sharing methods to do this.
Other references:
How is ID's list managed?
Our research shows [ h/t Nejc Zdovc ] that the list is server-managed by Apple WebPrivacy service and is cached in Webkit device cache.
What's a good way to test?
iOS26: https://www.apple.com/os/ios/
Safari Desktop: https://developer.apple.com/safari/technology-preview/
What do AI engines say?
OK accurate but no depth - https://chatgpt.com/share/68b8fda7-ee2c-8005-9bff-10ab2c76b42b
Humans win in detail so far!
What is the next article:
Impact is the iOS26 Martech impact and the uncertainty on what next Apple does?