Customer List Formatter for Snapchat Custom Audiences

How to build a Snapchat custom audience file

A Snapchat custom audience made from your customers is called a Customer List Audience (Snap used to call it Snap Audience Match). Snap's Create a Customer List Audience page asks for one column and one identifier type per file. Real exports have emails, phones and app IDs side by side, so this tool splits them up and fixes the phone format Snap is strict about.

1. Add your export. From a CRM, loyalty program, Shopify or an app database. Use Try sample data for a quick demo.
2. Map the columns. Email, phone, mobile ad ID and a country column are found automatically. You can select two email or phone columns at once.
3. Set a default country. Numbers like (415) 555-0132 get the code of the row's country, or of this default when the row has none.
4. Pick plain or SHA-256, and .csv or .txt. Plain is fine, because Ads Manager hashes in your browser anyway.
5. Download each file. You get up to three: emails, phone numbers and mobile ad IDs, each one value per line.

Snap's normalization, step by step

• Emails: trim spaces, then lowercase. [email protected] becomes [email protected].
• Phones: country code added, 00 and the national 0 removed, then only digits. 020 7946 0321 in the UK becomes 442079460321 — no plus sign.
• Mobile ad IDs: lowercase, hyphens kept. 6D92078A-8246-… becomes 6d92078a-8246-….

These rules come from Snap's normalizing and hashing FAQ. They matter most when you hash yourself: one extra space or a capital letter gives a different hash, and the person is not found.

Upload the files in Snapchat Ads Manager

1. Open Ads Manager, click the menu at the top left and choose Audiences.
2. Click New Audience › Custom Audience › Customer List.
3. Drag in the email file (or click to upload it). If it is hashed, choose hashed emails when Ads Manager asks.
4. Enter an audience name and description, then click Upload.
5. To add the phone or ad ID file to the same audience, open it from Audiences, choose Edit and Add users.

The same Edit screen lets you remove people or replace the whole list later. Ads Manager also offers example files above the upload box if you want to compare.

Snapchat customer list problems and fixes

Emails and phones in one file

Two columns, or a mix of values in one column, is the classic mistake. Snap supports a single type per file. Use the separate downloads from this tool.

Snapchat customer list phone number format wrong

US exports often drop the country code, and European ones keep the leading 0. Snap asks for the code on every number and no 0 after it. Numbers we could not place are listed with the reason, such as “too short” for a 5-digit value.

Pre-hashed file, wrong type chosen

When you upload hashed data, Ads Manager asks whether it is hashed emails, hashed mobile advertising IDs or hashed phone numbers. Picking the wrong one means nothing matches. The file names from this tool say which is which.

Upper-case ad IDs

Many iOS exports write IDFAs in capitals. Snap wants them lowercase with the hyphens left in. Reddit wants Apple IDFAs in upper case, so do not reuse this file there.

Audience smaller than expected

Snap does not match customer data to accounts of people aged 13 to 17 in the UK and the EEA for personalized ads. It also deletes unmatched customer data 30 days after upload, so add new customers again later instead of expecting old rows to match.

Very large files

There is no hard size limit, but Snap suggests staying under 1 GB. The tool splits a bigger list into parts.