SmsGateWay24 Платформа для общения с клиентами в SMS и WhatsApp

How to check and validate your SMS contact list

Every message sent to a wrong, duplicated or unsubscribed number costs you money and hurts your delivery reputation. Cleaning your list before a campaign is the single easiest way to raise delivery rates and protect your sender reputation.

Follow these four steps before you press send. SmsGateWay24 normalizes and checks numbers for you on import, so most of this happens automatically.

Начать бесплатный пробный период Learn about SMS types
1

Normalize numbers to E.164

Store every number in the international E.164 format — a plus sign, country code and subscriber number, with no spaces or dashes (for example +49 151 12345678 becomes +4915112345678). SmsGateWay24 uses the Google libphonenumber library to detect the country and reformat numbers automatically when you import a list.

2

Remove duplicates

The same customer often appears more than once — imported from different files or saved with and without a country code. Once numbers are normalized, duplicates become identical and are easy to collapse into a single contact, so nobody receives your message twice.

3

Drop invalid numbers

Numbers that are too short, too long or have an impossible country or area code will never deliver. Validation flags these so you can remove them before the campaign runs, instead of paying for messages that bounce.

4

Honor opt-outs

Anyone who replied STOP or asked to unsubscribe must be excluded from marketing sends. Keeping a suppression list is both good practice and a legal requirement under rules like GDPR, and it keeps complaint rates low.

Why a clean list matters

Higher delivery rates
Valid numbers deliver, so more of your audience actually receives the message.
Lower cost
You stop paying to text numbers that cannot receive your message.
Better compliance
Respecting opt-outs keeps you on the right side of consent rules and carrier policy.

Frequently asked questions about contact list validation

E.164 is the international standard for phone numbers: a plus sign followed by the country code and the national number, with no spaces or symbols, up to 15 digits. It is the format carriers expect for reliable international delivery.

Yes. When you import contacts, numbers are parsed with the Google libphonenumber library, reformatted to E.164 and flagged if they are not valid for their country.

Keep a suppression list of anyone who replied STOP or asked to opt out, and exclude them from marketing campaigns. Transactional messages such as order updates can still be sent where allowed.

Validate on every import, and review your full list periodically — numbers change hands and people opt out over time, so a list decays if it is never maintained.

Import a clean list and start sending

SmsGateWay24 validates and de-duplicates your contacts automatically on import.

Начать бесплатный пробный период Read the OTP guide