Free tool · runs in your browser
Customer list hasher for Google and Meta Ads.
Turn your customers' emails and phone numbers, the personally identifiable information (PII) that Google Ads Customer Match and Meta Custom Audiences require you to hash, into scrambled SHA-256 codes. Each platform wants the data formatted differently. This tool handles both, and your contact data never leaves this page.
Your customer list stays on your own computer. Full stop.
Everything happens right here, on the device you are reading this on, inside your web browser. Your customers' emails and phone numbers are never sent to leapbuzz, and never sent to anyone else. We do not receive them. We do not store them. We could not see them even if we wanted to.
Want to be sure? Once this page has finished loading, switch off your wifi. The tool still works perfectly, because nothing ever needs to leave your machine. Here is exactly how that works.
What this does, in plain English. Google and Meta let you upload your customer list so your ads reach those exact people. You should never upload raw emails or phone numbers. Instead each one is turned into a one-way code (a "hash"), for example [email protected] becomes 831f6494.... The same email always makes the same code, so the platforms can match your customers without ever seeing their real details. This tool does that scrambling for you.
The tool auto-detects your email and phone columns, and assumes numbers already include their country code.
Step 1
Put your customer list in
Choose one: paste the list straight in, or upload a file from Excel or Google Sheets.
File format. Use one of these two layouts:
- One column. A list of emails only, or a list of mobile numbers only, one per row. Keep a single column to one type.
- Two columns. An email column and a mobile column, one person per row. A header row like
email,mobileis fine.
Extra columns such as names are ignored. Only the first sheet of an Excel file is read. Download a sample CSV to try it.
Drop a .csv, .xlsx or .xls file here, or click to browse.
Step 2
What do you want to hash?
Pick one or both. The tool only reads the fields you choose.
Mobile number settings
A country code is required for phone matching on both platforms. Tell us what your numbers look like.
Why two files? Google Ads wants the phone hashed with a plus sign, like +6591234567. Meta wants it hashed as digits only, like 6591234567. The tool builds both for you, so the email hash stays identical across the two files and only the phone format differs.
Waiting for your list.
Step 3
Download your safe file
Pick the platform you are using. Each file is already in the exact format that platform needs.
These files contain only the scrambled codes. No real email addresses and no real phone numbers are ever written to the file. Safe to upload to the ad platform.
Google Ads format
Phone hashed in E.164 form, with the + prefix. This is the format Google Ads Customer Match documents.
Meta Ads format
Phone hashed as digits only, no +. This is the format Meta Custom Audiences documents.
Using another platform? The email hash is the same standard everywhere: the address lower-cased, trimmed, then SHA-256. That makes an email-only file widely compatible across platforms that accept hashed lists, including Microsoft Advertising, LinkedIn, TikTok, Snapchat, X, Reddit, Pinterest, and Amazon Ads. Phone formats vary, and a few platforms apply their own extra rules, so always confirm the current spec in the platform you are uploading to.
| # | Email SHA-256 | Phone | Phone SHA-256 (Google) | Phone SHA-256 (Meta) |
|---|
The table is a preview so you can sanity-check it. It shows the first 200 rows. Your downloaded file has every row and contains only the scrambled codes.
What do I do with the file now?
Google Ads: Tools, then Shared Library, then Audience Manager, then the plus button, then "Customer list", then upload google_ads_customer_match.csv. Tick the box that says your data is already hashed.
Meta Ads: Ads Manager, then Audiences, then Create Audience, then "Customer list", then upload meta_custom_audience.csv. Meta accepts the hashed file directly.
How it works
How does hashing a customer list for Google and Meta Ads work?
One-way by design
SHA-256 turns any text into a fixed 64-character code. You cannot run it backwards to recover the email or number. The platforms hash their own users the same way, then match the codes. Your raw list is never part of the exchange.
Computed in your browser
The scrambling uses your browser's own built-in cryptography, the same kind your browser uses for secure HTTPS websites. The page makes no network request with your data. The only thing it can ever load is a small spreadsheet reader for Excel files, served from this site, and even that never sees your contacts.
Hashing protects the data in transit, not the strategy behind it. If you want the audience strategy that makes Customer Match and Custom Audiences actually pay back, that is the work we do on paid social and AI performance marketing, across Google Ads and Meta Ads.
Questions
Customer list hashing, answered.
Does any of my data get uploaded to leapbuzz?
No. The scrambling runs entirely inside your own browser, using the browser's own built-in cryptography, the same kind it uses every day for secure HTTPS websites. Your customer list is never sent to leapbuzz or to anyone else. The simplest proof: switch off your wifi once the page has loaded, and the tool still hashes and downloads perfectly, because nothing it does needs the internet.
What is a SHA-256 hash?
It is a one-way scramble. Any input produces a fixed 64-character code, and the same input always produces the same code. You cannot reverse it back to the original email or number. Google and Meta require hashed data for Customer Match and Custom Audiences so they can match customers without exchanging raw contact details.
Why are the Google and Meta files different?
Only the phone format differs. Google Ads Customer Match hashes the phone in E.164 form with a plus sign, for example +6591234567. Meta hashes the phone as digits only, for example 6591234567. The email hash is identical across both files. This tool produces each platform's file in the correct form.
Do my phone numbers need a country code?
Yes. Both platforms need the country code for phone matching to work. If your numbers already include it, the tool uses them as they are. If they are local numbers, choose your country in Step 2 and the tool adds the correct code before hashing. The plus sign in your input does not matter, the tool normalises it.
What file formats can I use?
Paste text, or upload a CSV, XLSX, or XLS file. CSV and paste work fully offline. Reading an Excel file loads a small spreadsheet library from this site once. A one-column or two-column layout both work, and the tool auto-detects which column is email and which is phone.
Can I use this for TikTok, Microsoft, LinkedIn, or other platforms?
Often, yes. Most major ad platforms accept SHA-256 hashed customer lists, and the email hash is the same standard everywhere, so an email-only file is widely usable. Only the Google format (with the plus sign) and the Meta format (digits only) are independently verified and built into this tool. Platforms such as Microsoft Advertising, TikTok, LinkedIn, Snapchat, X, Reddit, Pinterest, and Amazon Ads also accept hashed lists, but their phone rules vary, so confirm the current spec in that platform before you upload a phone file.
Is the tool free to use?
Yes, the tool is free and needs no sign-up. We built it because clients kept asking how to prepare customer lists safely. If you want help turning matched audiences into performance, talk to us.
Matched the audience. Now make it pay back.
Customer Match and Custom Audiences are a starting line, not a strategy. We run paid social and Google Ads for regulated and high-consideration brands across five markets. A senior practitioner will read your actual setup, no deck, no templates.
Talk to us