Cookie Sync

Overview

Cookie syncing allows Nexx360 to share user identifiers with demand partners, improving match rates and bid performance. There are two approaches: passing IDs directly in the bid request, or using Nexx360's cookie sync endpoints.

ID Sharing via Bid Request

When a seller is already synced with third-party partners, they can share user IDs through the user.ext.eids field in the OpenRTB request.

EID Format

{
    "source": "adnxs.com",
    "uids": [
        {
            "id": "6193521930111213563"
        }
    ]
}

Cookie Sync Endpoints

Nexx360 provides two cookie sync endpoints that DSPs can use to sync user IDs with Nexx360.

Redirect Endpoint

GET https://fast.nexx360.io/usermatchredir/redirect

This endpoint reads the Nexx360 user cookie (xxuid), and if a redirect URL is provided, replaces the $UID macro with the user ID and redirects the user to that URL.

Query Parameters

Parameter	Required	Description
gdpr	No	GDPR applies flag (0 or 1)
gdpr_consent	No	TCF consent string
us_privacy	No	US Privacy (CCPA) string
gpp	No	Global Privacy Platform string
gppsid	No	GPP Section ID
redir	No	URL-encoded redirect URL with $UID macro

Example

https://fast.nexx360.io/usermatchredir/redirect?gdpr=0&redir=https%3A%2F%2Fdsp.com%2Fsync%3Fuid%3D%24UID

This will redirect the user to https://dsp.com/sync?uid=<xxuid> where <xxuid> is the Nexx360 user ID.

Behavior

• If GDPR consent is required but not valid, returns 200 with no sync.

• If no xxuid cookie is present, returns 204.

• If no redir parameter is provided, the cookie is refreshed and returns 204.

• If a valid redir is provided, replaces $UID with the user ID and responds with a 302 redirect.

• Only the $UID macro is supported. Other macros will return a 400 error.

Iframe Endpoint

GET https://fast.nexx360.io/usermatchredir/iframe

This endpoint returns an HTML page that can be loaded in an iframe. The page embeds the Nexx360 user ID and privacy parameters, then executes a cookie sync script that handles syncing with multiple demand partners.

Query Parameters

Parameter	Required	Description
gdpr	No	GDPR applies flag (0 or 1)
gdpr_consent	No	TCF consent string
us_privacy	No	US Privacy (CCPA) string
gpp	No	Global Privacy Platform string
gppsid	No	GPP Section ID
redir	No	URL-encoded redirect URL

Example

<iframe src="https://fast.nexx360.io/usermatchredir/iframe?gdpr=0" style="display:none"></iframe>

Behavior

• Returns an HTML page with a window.cookieSyncRedir object containing the privacy config and xxuid.

• If GDPR consent is required but not valid, the page is returned without the xxuid.

• The embedded script handles syncing with demand partners automatically.

Supported Sync Partners

Partner	Cookie Domain
AdaptMX	a-mo.net
Adform	adform.net
Adot	adotmob.com
Adyoulike	omnitagjs.com
Appnexus (Xandr)	adnxs.com
Bidswitch	bidswitch.net
Bliink	bliink.io
Colossus	colossusssp.com
ConnectAd	connectad.io
Conversant	dotomi.com
e-Planning	e-planning.net
Freewheel	stickyadstv.com
GumGum	gumgum.com
Improve (Azerion)	360yield.com
Index Exchange	casalemedia.com
Media.net	media.net
NextMillennium	nextmillmedia.com
OneTag	onetag-sys.com
OpenX	openx.net
Outbrain	zemanta.com
Pubmatic	pubmatic.com
PulsePoint	contextweb.com
RichAudience	richaudience.com
Rise	yellowblue.io
RTB House	creativecdn.com
Rubicon (Magnite)	rubiconproject.com
Sharethrough	sharethrough.com
Smaato	smaato.net
Smartadserver (Equativ)	smartadserver.com
Smilewanted	smilewanted.com
Triplelift	3lift.com
The Trade Desk	adsrvr.org
Yieldlab	yieldlab.net