Number Filtering Data for Ad Retargeting: Format Requirements, Platform Integration, and Compliance Practical Guide

In overseas marketing, ad retargeting is one of the core methods to improve conversion rates. However, many teams directly import large volumes of unverified numbers into ad platforms, resulting in match rates below 30%—budgets are wasted on invalid numbers and zombie accounts. Number filtering data is the upstream engine that solves this problem: by performing activation checks, activity screening, and gender identification, raw numbers are transformed into high-quality retargeting lists, which can then be integrated with ad platforms in the correct format to achieve high ROI. This article will break down the complete practical path from number filtering to retargeting, covering format requirements, platform differences, export methods, and compliance tips.

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Why Number Filtering Data Is the “Upstream Engine” for Ad Retargeting

Unfiltered number lists often contain a large proportion of numbers that are deactivated, inactive for a long period, or incorrectly attributed. Ad platforms match retargeting lists based on user identifiers (e.g., phone numbers, emails). If the list has too many invalid numbers, not only is the match rate low, but money is also wasted on ineffective impressions. By using a filtering tool to perform activation checks, activity level assessments (e.g., online within 7/15/30 days), and gender identification, and then creating segmented lists based on target groups (e.g., recently active female WhatsApp users), you can significantly improve retargeting click-through and conversion rates.

The Core of Retargeting: List Quality Determines Ad Returns

• Invalid numbers waste budget: The ad system tries to match every number—empty or invalid numbers yield no matches but still incur costs.
• Activity affects reach: Even if a long-inactive number is matched, the user won’t see the ad, lowering the system’s interest evaluation.
• Gender/labels optimize creatives: With gender identification from the filtering tool, you can prepare different ad materials for male and female groups, boosting CTR.

How Number Filtering Data Flows into Ad Retargeting

The overall process can be summarized as:
Raw numbers (self-built lists/global generation) → Filtering (activation check, activity, gender identification) → Deduplication → Export (CSV/TXT) → Format conversion (if necessary) → Import to ad platform (Google Ads / Facebook / TikTok, etc.) → Create retargeting ad group.

Among these, format consistency is key to smooth data flow. Each platform has different requirements for file fields, encoding, and hashing methods—a small mistake can cause upload failures.

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General Format Requirements for Ad Retargeting Lists

Regardless of which ad platform you use, retargeting list files typically share the following conventions:

• File format: CSV or TXT (plain text); some platforms accept Excel (.xlsx).
• Encoding: UTF-8 (without BOM) is recommended to avoid garbled characters for Chinese or special symbols.
• Delimiter: CSV commonly uses commas or semicolons; TXT usually expects one number per line without a header.
• Number format: Must include the international country code, starting with ”+” (e.g., +8613800138000). Most platforms require the E.164 format (+[country code][number], no spaces or parentheses).
• Column header naming: Some platforms use headers to clarify field meanings (e.g., “Phone”, “Email”). If using a template upload, keep the headers consistent with platform requirements.

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Differences in Data Format for Retargeting Lists Across Major Ad Platforms

Different platforms have varying requirements for list fields, hashing methods, and capacity limits. Below is a summary of major differences among Google Ads, Facebook/Instagram, and TikTok:

Platform	Common Field Requirements	Hashing Method	File Size Limits	Notes
Google Ads	Phone number (with country code), email, address, etc.	Plaintext or SHA256	Up to 100,000 rows (direct upload); larger via API	Numbers should be in E.164; supports multi-field combination matching
Facebook / Instagram	Phone number (with country code), email, mobile ad ID	Must be SHA256 hashed	Up to 1 million entries (Custom Audience)	Plaintext numbers will be rejected by Facebook—must hash yourself
TikTok for Business	Phone number (with country code), email	Plaintext or SHA256	Up to 20,000 entries (Contact Group)	Hashing is not yet mandatory, but recommended for privacy protection
LinkedIn	Email primarily, phone secondary	Plaintext (email)	Up to 300,000 entries	Phone match rate is relatively low

Google Ads: Fields and Format for Customer Match Lists

• Supported fields: Phone number, email, name + address, mobile device ID, etc.
• Number requirements: Must be in E.164 format (e.g., +8613901234567), no spaces, hyphens, or parentheses.
• Column order: Official template suggests the first column is “Phone”, second is “Email” (optional). If you only upload numbers, a single column is fine; name it “Phone” for clarity.
• Operation tip: When exporting from KK-DATA, select “Phone number only” and check “Include country code” to directly obtain an E.164 formatted CSV without secondary processing.

Facebook/Instagram: Upload Specifications for Custom Audiences

• Field requirements: Phone number (must include country code), email, ID, etc.
• Mandatory hashing: Facebook requires phone numbers to be SHA256 hashed before upload. Plaintext numbers will cause upload failure or zero match rate.
• Post-export processing: Use a simple script (e.g., Python’s hashlib) or an online hashing tool to convert each plaintext number from KK-DATA export to SHA256 uppercase (Facebook requires a 64-character uppercase hex string). Keep a backup of the original numbers for use on other platforms.
• Capacity: Up to 1 million entries; you can create multiple audience groups.

Emerging Platforms like TikTok and RED (Xiaohongshu): Format and Contact Groups

• TikTok Contact Groups: Supports uploading phone number lists (single-column CSV/TXT); hashing is not mandatory but SHA256 is recommended. Single uploads are limited to about 20,000 entries, suitable for small-scale testing.
• RED (Xiaohongshu): Currently, the official platform has not opened phone number retargeting (only device IDs or in-app user IDs are supported); if it opens in the future, it is expected to follow domestic privacy compliance requirements (user consent + encrypted transmission). Refer to the latest official documentation.

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How to Export Filtering Results into Retargeting-Compliant Lists

Using KK-DATA as an example, its multi-format export feature allows flexible adaptation to different ad platform requirements. Here are the practical steps:

Field Selection Before Export: Only Keep Columns Needed by the Ad Platform

Filtering results usually contain multiple detection data: tgid, wsid, active days, gender judgment, etc. Exporting all fields directly results in large file sizes and confusing field mapping during upload. Suggested:

1. On the task result page, click “Export” and select CSV or TXT.
2. In “Export Fields”, only check “Phone number” (with country code) and “Platform identifier” (e.g., if you only need WhatsApp numbers, filter in advance).
3. If you need segmented lists (e.g., “Active WhatsApp females”), filter by activity and gender first, then export different files.

Deduplication and Merging: Avoid Delivering Ads to the Same Number Multiple Times

When importing across tasks, the same number may appear in multiple filtering tasks. If merged and uploaded directly, the ad platform will reject files with duplicate records (some platforms merge duplicates but may issue warnings). KK-DATA’s Data Dedup Repository can compare across tasks and output a unique number list. Suggested:

• After each filtering session, first import the results into the dedup repository.
• Export the deduplicated list from the repository, then split into separate files for each platform as needed.
• For large lists (over 100,000), export in batches to keep file sizes within platform limits.

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Data Compliance Points for Ad Retargeting (GDPR, CCPA, etc.)

Overseas enterprises must note that filtering only verifies the validity and activity of numbers—it does not grant you the legal right to use these numbers for ad retargeting. Ad platforms have strict audits on data sources; non-compliance may lead to account suspension or legal risks.

Core Rules You Must Follow

• User Consent: Ensure the numbers you upload come from users who have explicitly agreed to receive promotional marketing (e.g., checked “I accept advertising” during registration). Never use publicly scraped or purchased numbers directly for retargeting.
• Data Source Legitimacy: Google and Facebook require you to declare the list source as “voluntarily provided by users” or “directly collected”. If you use a third-party filtering tool (e.g., KK-DATA), that platform only provides detection services, not number sources.
• Retention Period: GDPR requires that personal data is not stored longer than necessary; regularly update retargeting lists to remove expired or unsubscribed numbers.
• Opt-out Mechanism: You must provide a clear unsubscribe/opt-out option in your ads; otherwise, you may violate laws such as CAN-SPAM.

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Best Practices: Full Workflow from Filtering to Retargeting

1. Test with a small batch before full-scale launch: Spend 10 USDT to test filter 5,000 numbers, observe match rate and conversion, optimize audience criteria, then scale.
2. Create separate ad groups by activity level: Separate “WhatsApp users active within 7 days” from “inactive for 30 days”; use the former for core conversion ads and the latter for wake-up offers.
3. Leverage gender identification for differentiated creatives: Export male/female lists separately and design H5 pop-ups, images, or copy tailored to each gender.
4. Regularly update lists to remove invalid numbers: Re-filter your existing list monthly to remove deactivated or long-inactive numbers, keeping the list fresh.
5. Consistently export in E.164 format: When exporting, always use “+country code + number” to reduce upload errors.
6. Export separate files for each platform: Don’t upload the same list to both Google Ads and Facebook—avoid field confusion; if needed, export separately and label clearly.
7. Track expenditure and returns: Use KK-DATA’s cost estimation feature to compare filtering costs with retargeting ROI, continuously optimizing budget allocation.

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Frequently Asked Questions (FAQ)

Q: Are the phone numbers exported after filtering plaintext or encrypted? Can they be uploaded directly to Facebook?

A: KK-DATA supports TXT/CSV export, outputting plaintext phone numbers (with country code) by default. Some ad platforms (e.g., Facebook) require phone numbers to be uploaded in SHA256 hashed form. It is recommended to hash after export; see platform documentation. For Google Ads and TikTok, plaintext can be uploaded directly.

Q: Can one retargeting list be used for both Google Ads and Facebook? Does it need format changes?

A: Usually not directly interchangeable. Google Ads and Facebook have different field, column name, and hashing requirements. It is recommended to export separately for each target platform, or manually adjust after exporting once from KK-DATA. Do not upload the exact same file to different platforms to avoid data conflicts.

Q: If the retargeting list contains invalid numbers, how does the ad system handle it?

A: Most ad platforms will automatically filter invalid numbers (e.g., empty numbers), but they still consume matching budget. Filtering out invalid numbers in advance using KK-DATA can improve match rates and reduce costs. Additionally, some platforms may limit list uploads if the invalid rate is too high (e.g., Facebook requires an invalid rate below 30%).

Q: Do I need user consent to use filtered data for retargeting?

A: Yes. Most countries’ privacy laws (e.g., GDPR, CCPA) require retargeting based on explicit user opt-in. Filtering itself does not grant rights. Only import phone numbers for which you have obtained user consent for marketing into ad retargeting. Make sure your user agreement and privacy policy cover the “retargeting” scenario.

Q: Is KK-DATA’s billing model suitable for batch retargeting scenarios?

A: Yes. KK-DATA has no subscription plans; it charges per record, making it ideal for irregular, multi-batch, large-volume filtering in retargeting. You can estimate costs in the console before submitting tasks. When balance is insufficient, you can recharge anytime with USDT—no monthly fees.

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For more filtering and data management tips, visit the KK-DATA Official Documentation or log in to the Console to generate numbers for free. If you have questions about format integration or compliance, feel free to contact Telegram support @kkdata_robot (please verify it is the official account to avoid impersonation).