Proxy and device/geo targeting

The majority of email traffic on our network happens via proxies, such as Gmail, Yahoo, Outlook or Apple. Some of them, such as Apple Proxy preload every image in emails, leading to inflated impression rates. This requires adapting your bidding strategy to ensure you value each segment of the traffic accurately.

While you can use the User Agent to detect some of the proxies, others may also require looking up the ISP from the IP, or relying on IP ranges data set from the different email / proxy vendors.

Our system will pass the result of that detection in the OpenRTB device.make field. The following values are currently present:

• Apple Proxy
• Gmail Proxy
• Outlook Proxy
• Yahoo Proxy

You can expect the following average distribution for the bid requests from our network

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Traffic geo-location

Proxies also hide the full geo-location. From our experience, you can trust the country (US, CA, FR, etc.) but anything lower such as state or city will suffer from a significant mismatch rate.

For example, Apple proxy (also referred to as Apple Mail Privacy Protection or iCloud Private Relay) when configured by the user in coarse mode will try to match the user timezone but the state or city may be significantly off.

We recommend only relying on the country level when targeting proxy traffic. Desktop/mobile traffic can use the full range of geo-location information, similar to web traffic.

Performing your own proxy detection based on UA or IP

If you prefer to perform your own detection for proxies, you can find our current logic below. Note that this is subject to change as new proxies enter the market, or as we refined the detection to eliminate IVT and traffic of dubious provenance.