Use the right encoding
Not all phones support all languages. For instance, sending a Chinese message to a French phone will get to the handset but will not display to the user. Sending binary messages to an iPhone won’t work, either.
Not only is it illegal, more often than not, it doesn’t work. Most likely the message will not arrive at the handset and you will still be stuck paying for it. Spam filters have become very good at detecting spam attacks.
Certain carriers also filter some keywords (such as the carrier’s own name) to prevent brand theft and scams.
Vary the wording in your message body
When sending campaigns, it is better to randomize the order of the body of the message, if you can. If you are sending a an opted-in marketing campaign or many password codes at once, come up with more than one version of the content and change it randomly. For example:
Message 1: Your Pin Code is 2234
Message 2: Please enter 2234 into your application to verify your account
Format the Destination Address
Make sure to format the “to” field in international format, including the correct country code. Please refer to the ITU’s International Numbering Resources:
ITU Numbering Plan: http://www.itu.int/oth/T0202.aspx?parent=T0202
It is not necessary to include dialling prefixes such as + or 00, but if you have no choice (because of compatibility with other services for example) we can accommodate this formatting.
If sending for your clients, do not rely on them to use the correct formatting. There are libraries available that can help you automatically find the right format, i.e.: Google Lib
A badly formatted number will be rejected, so we recommend you track rejections and optimize according to this feedback.