How to clean a phone list before SMS and WhatsApp: 2026 checklist

Dirty phone lists burn budget: carrier blocks, WhatsApp reputation hits, higher CPA and subscriber complaints. Here is a proven hygiene pipeline on Cheker.pro before every large campaign.

Why clean before sending

Bulk SMS and messenger campaigns penalize dead numbers, VoIP lines and missing opt-in. Technical cleaning does not legalize cold spam, but removes 20–40% of useless traffic before send.

Step 1. Legal basis

Document opt-in, contract or lawful interest. Cheker.pro acts as processor — you set retention (30–90 days) and consent policy.

Step 2. Dedup & E.164

One number per line, international format with country code. Strip spaces, brackets, local trunk prefixes. Export CSV from Excel without scientific notation.

Step 3. Phone Number Validation

phonecheck — format, line type (mobile/landline/VoIP), basic reachability. Cheapest layer before expensive ws/tg.

Step 4. Number Active Checker

active_check — SIM activity signal. Critical before SMS: stop paying for dead lines.

Step 5. Messenger checkers

Separate tasks: WhatsApp, Telegram, Viber. Waterfall: WA → TG → SMS for remainder.

Step 6. Carrier detection

Global carrier / US Carrier Premium for SMS routing and landline exclusion.

Success metrics

• 25–35% fewer undelivered SMS
• Higher OR on WhatsApp «yes» segment
• Fewer spam reports and template blocks

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