SMS Length
The total length of a standard SMS message should be within 160 characters if you do not use diacritical marks (e.g., accents). If you use characters with diacritics (like á, č, ř), you must be aware that the limit for a single SMS drops to 74 characters. If you send a longer message, it will be split into multiple parts (which increases costs), or it should be sent without diacritics.
Links in SMS
We use a link shortener for URLs, and each shortened link will use 21 characters of your message. Always enter the full link, including the protocol (e.g., https://www.incomaker.com, not just www.incomaker.com), otherwise, click-throughs cannot be tracked. The link shortener can be disabled in your account’s general settings; however, please note that if you disable it, you will not be able to track the performance (click-throughs) of your SMS campaigns.
Commercial Messages
For SMS messages, we recommend adding the prefix “OS” (a Czech abbreviation for Obchodní sdělení, or Commercial Message) before the main text. This identifies the message as commercial communication and helps prevent the SMS gateway from potentially flagging your messages as spam.
Unsubscribing from SMS
Just as with email campaigns, every customer must have the option to unsubscribe from SMS messages. The easiest way is to create a landing page with an unsubscribe form. After a contact confirms their unsubscription, they can be added to a special suppression list (e.g., named “Do Not Send SMS”), which you then exclude when selecting the audience for future SMS campaigns. You can therefore include a link to this unsubscribe landing page at the end of every SMS message you send.
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