Character support

When specifying the message body in the request, the characters used as well as the length of the message affect how many actual SMS messages are sent out. When using parameterization, the length of each message may also vary depending on the recipient-specific data.

Individual characters used in the message determine the type of encoding that will ultimately be used to send the SMS message. The API automatically detects the encoding required from the characters used, which allows us to support the delivery of SMS in any language.

Basic character set

You can send up to 160 characters in a single SMS message if all characters in your message are part of the GSM 7-bit character set:

GSM 7 bit default alphabet and extension table

3GPP TS 23.038 / GSM 03.38

LF is the Line Feed character - for JSON format, provide it as \n SP is the Space character

Extended Character Set

The following characters are also available, but they're counted as two characters in the SMS message rather than one:

| , ^ , € , { , } , [ , ] , ~ , \

Other Characters

If other characters are required for different languages, 16-bit Unicode (UCS-2) encoding will be used. When using UCS-2 encoding, each character will take 2 bytes, which means up to 70 characters can be sent per UCS-2 encoded SMS message.

Long Messages

The message body in a request can contain a maximum of 2000 characters. However, 7-bit encoded messages allow up to 160 characters in one single message. Unicode encoding allows for up to 70 characters in a single message. And the header of each message takes up a few characters. So how can we accomplish up to 2000 characters? We use multiple messages that, in most cases, reassemble on the user's device. To your customers, it looks like one long message. You can use the charts below to determine how many actual SMS messages your text contains.

Note that messages longer than 2000 characters will result in a 400 error.

Using only 7-bit Characters

Each SMS in a multi-part 7-bit encoded message has a maximum length of 153 characters.

Using Unicode Characters

Each SMS in a multi-part Unicode encoded message has a maximum length of 67 characters.