Client Hints FAQ for Singular Partners (Chromium User Agent Reduction)

What are client hints?

New versions of Chromium-based web browsers (such as Google Chrome and Microsoft Edge), rolled out from February to April 2023 (for mobile), will limit the availability of user agent data, which includes information about the user's device model, version, etc.

The same data will now be available through client hints instead. With client hints, the server has to actively ask for the data, as well as give permission to have it shared with third parties.

For more information, see the Chromium developer documentation for Client Hints and the new Permissions Policy.

What is the release timeline for client hints?

Client hints were rolled out gradually to mobile devices starting in February 2023.

How do client hints affect Singular functionality?

In the past, Singular was able to use the user agent data sent from the browser in the probabilistic attribution process. We now need to use client hints instead to access the same data.

In cases where client hints are not available to Singular, we need our partners to fetch the client hints and add them to the click/impression's link query parameters.

This depends on the type of click or impression sent by partners to Singular:

Click/Impression Type Required Changes
Clicks that go through Singular’s redirect link from the browser Nothing is needed from the partner. Singular will support client hints.
Clicks that do not go through our servers (e.g., S2S clicks, a tracking link is pinged but the user is not redirected through it)

The partner needs to send us the following data in the tracking link using Singular's dedicated parameters.

Note: do not forward the client hints as headers!

Singular Parameter Description Client Hint Request Header
p platform  ch-ua-platform
ve OS version