In this guide
- Customer Match uses hashed e-mail, phone and address that you collected with consent to build audiences in Google Ads.
- Format first, then hash with SHA-256. Lower case, trim spaces and use international phone format.
- Use it to target customers, exclude buyers and build similar audiences. Refresh the list regularly.
A customer list is the most reliable audience you can build now that third-party cookies are fading. You already know these people: they bought, signed up or asked a question. Google Ads can match your list to signed-in Google accounts and let you reach them or leave them out. This page walks through the preparation, the upload and the pitfalls. Google's eligibility rules and limits change, so check its Customer Match help page before you start.
What it is good for
Remarketing to customers
Show a new product or a reorder reminder to people who bought before.
Excluding buyers
Stop paying to show acquisition ads to people who already bought.
Finding similar people
Use the list as a seed for broader, similar audiences where Google offers it.
Better bidding signals
A list of high-value customers helps Google understand what a good customer looks like.
Ask Ari instead of digging through reports
Ari reads your tracking and ad data and answers in plain words.
Prepare the data
| Field | Format before hashing |
|---|---|
| Lower case, no spaces. For Gmail, follow Google's current rule on dots. | |
| Phone | International format with country code, digits only, for example +14155550123 |
| First and last name | Lower case, no punctuation |
| Country and zip | Two-letter country code and the postal code, as Google asks |
Hash e-mail and phone with SHA-256 after formatting. Hash once. If you use Google's upload tool, it can hash in your browser for you.
Upload
Open Audience manager in Google Ads
Tools, Audience manager.
Create a customer list
Choose to upload a list of customer data.
Pick the data type
E-mail, phone, address or mobile device IDs.
Upload the file
A CSV with a header row, or use the API or a connected tool.
Choose how long people stay in the list
A membership duration, up to the maximum Google allows.
Wait for the match
It can take many hours before the list is usable.
Connected in minutes
Add your domain, install the pixel, connect your ad platforms and watch the first events land.
Consent and policy
You must have collected the data lawfully and have the right to use it for advertising. In the EEA and UK, Google's EU user consent policy asks you to have obtained consent. Do not upload people who asked to be removed. See server-side tracking and GDPR.
Keep it fresh
Upload a fresh list on a schedule, such as weekly or monthly, with new buyers added and unsubscribed people removed. A stale list loses its value and can break policy. Many teams automate it from their shop or CRM, or from the Data Store of a tracking server.
Common errors
A realistic plan for a small store
Start with the list you already have: everyone who bought in the last twelve months. Export their e-mail and phone from your shop, format them, and upload them as one list. Create a second list for people who signed up to your newsletter but never bought. Use the first list as an exclusion in prospecting campaigns, so you stop paying to win customers you already have, and as a seed for similar audiences where Google still offers them. Use the second list for a gentle first-purchase offer. Keep the two lists separate so you can see what each one does.
Check the match rate a day or two later. A match rate of a third to a half of your records is not unusual, because only people who use their e-mail or phone with a Google account can be matched. If your rate is far lower, look at the formatting first, then at how many of your customers use a work address or a non-Google provider.
Terms you will see
- Customer Match
- Google Ads' name for audiences built from your own customer data.
- Match rate
- The share of your uploaded records that Google could link to an account.
- Membership duration
- How long a person stays in the list after they are added.
- SHA-256
- The hash function used to turn e-mail and phone into a fixed code.
- Exclusion
- An audience you tell a campaign not to show ads to.
Orders from your store, back to the ad that earned them
Your store sends the order once. Open Tracked passes it on to each ad platform, cleaned and deduplicated.
Frequently asked questions
What is Customer Match?
A Google Ads feature that lets you upload customer data to build audiences for targeting and exclusions.
Do I upload plain e-mail addresses?
You can upload hashed values. Format first, then hash with SHA-256. Google's tool can hash for you.
How big does the list need to be?
Google sets minimums for each use. Check the current help page.
How often should I update the list?
Weekly or monthly for most stores, and sooner after campaigns.
Is consent required?
You need a lawful basis, and in the EEA and UK Google asks for consent. Ask your advisor.
Do I need spreadsheets to read my results?
No. Once tracking is live, the Open Tracked analytics shows spend, revenue, ROAS and profit, and you can ask Ari, the built-in AI assistant, questions about your own numbers in plain words. Ari's allowance depends on your analytics plan.
Is Open Tracked different from Open Track or Open Space Track?
No. Open Tracked is the official name of our server-side tracking platform, and the website is opentracked.io. Many people search for it as Open Track, OpenTrack or Open Space Track. All of them lead to the same product: server-side Google Tag Manager hosting, first-party analytics and a CRM pipeline.
Fix your tracking at the source
Open Tracked hosts your server-side Tag Manager, keeps first-party cookies alive and shows what each ad is really worth.
The Open Tracked team
We build Open Tracked: server-side tracking hosting, analytics and the tools around them, for stores that spend on ads. Questions about this guide, or an idea for the next one?
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