Data and Tracking
You have customer data but do not use it for your advertising
Through Customer Match. With it you reach customers based on your online and offline data in Google Search, on the Shopping tab, in Gmail, on YouTube and across the Display Network g-cmatch. You can upload email addresses, phone numbers, postal addresses and customer IDs; the data is transferred hashed g-cmatch. Lists need upkeep: Google names a maximum membership duration of 540 days and at least 100 updated users g-cmatch.
What we do: We settle the legal basis first, cut lists by value, automate the refresh and measure new business separately; your customer data steers delivery, and budget goes to new business instead of existing customers.
By Robin Kardinal, Chief Operation Officer (COO)
Last updated on
What it is about and when it becomes relevant
What Customer Match can do
It brings your own customer data into the ad platform. Usable are email addresses, phone numbers, postal addresses and customer IDs, transferred encrypted g-cmatch. Delivery happens in Google Search, on the Shopping tab, in Gmail, on YouTube and across the Display Network; third-party creatives are not supported g-cmatch.
What it pays off for
Three things: deliberately excluding existing customers so budget flows into new business; weighting valuable customer groups higher; and deriving lookalike audiences from a good list instead of an arbitrary one.
What it requires
A legal basis for the use and a process that keeps the lists current. Google requires a refresh within 540 days and at least 100 updated users g-cmatch; a list uploaded once and forgotten goes stale.
Common mistakes and how you spot them
One list for everything
How you spot itThere is exactly one customer list without distinction by value, recency or product range. Statements about good and bad customers are impossible with it.
Existing customers not excluded
How you spot itThe share of existing customers among the conversions is high while total revenue stays flat. The budget buys revenue that would have come anyway.
Lists going stale
How you spot itThe audience's reach sinks slowly, and at some point Google reports the list as no longer usable. Membership ends after 540 days g-cmatch.
Legal basis unresolved
How you spot itNobody can say on what basis the addresses are used for advertising. That is not a marketing topic; it is one for your legal team.
How we go about it
Settle the legal basis first
We only build once it is settled which data may be used on which basis. That assessment sits with you; we implement the result.
Cut lists by value
Instead of one big list, groups emerge by customer value, recency and product range, because only then do exclusions and weighting become possible.
Automate the refresh
The transfer runs regularly instead of by hand, so the membership duration does not lapse g-cmatch.
Measure the effect separately
We report new business and existing customers separately, so the contribution becomes visible and does not vanish in the total.
Further reading
This topic belongs to Tag Management.
Frequently asked questions
Which data can I upload for Customer Match?
Email addresses, phone numbers, postal addresses and customer IDs. They are transferred hashed before Google matches them g-cmatch.
Where do Customer Match audiences get served?
In Google Search, on the Shopping tab, in Gmail, on YouTube and across the Display Network. Third-party creatives are not supported g-cmatch.
How often do I have to refresh the lists?
Google names a maximum membership duration of 540 days with at least 100 updated users g-cmatch. In practice, a regular automatic match pays off.
May I simply upload customer data?
That hangs on your legal basis and belongs settled with your legal team before the first list is built. We implement what was decided, and do not judge it legally.
Is this exactly where you are stuck?
Write to us about where it is stuck. Robin Kardinal and the team will look at what is concretely behind it in your case, and tell you where the biggest lever sits.
Sources
Every statement about ad products comes from the official documentation of the respective platform, with the date we retrieved it. Products change; if something looks outdated to you, write to us and we will check it.
- g-cmatchGoogle Ads-Hilfe, Kundenabgleichretrieved on 21.9.2026
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