SMTP API

Use our SMTP API to access our E-mail to SMS Messaging Service using your email system.

Interface call

Our SMTP API, just like our other services, does not rely on country-specific domains. You can access our email to SMS services using the domain based on the platform your account is on. If your account is on websms (https://app.websms.com), the domain will be email2sms.websms.com; if your account is on Linkmobility(https://app.linkmobility.eu), the domain will be email2sms.linkmobility.eu. To send an SMS, you must use the recipient's mobile number and the abovementioned domain as an email address.

The syntax contains the recipient's mobile number (MSISDN), for instance:

  • If your account is on the websms (https://app.websms.com), the syntax will be <msisdn>@email2sms.websms.com or 436761234567@email2sms.websms.com

  • If your account is on the Linkmobility (https://app.linkmobility.eu), the syntax will be <msisdn>@email2sms.linkmobility.eu or 436761234567@email2sms.linkmobility.eu

Following are the syntaxes for SMS, UCS-2 encoded SMS and voice calls.

  • For GSM-encoded text bodies, the interface can be called by sending an email to:
    <msisdn>@email2sms.websms.com or <msisdn>@email2sms.linkmobility.eu .

  • For interface calls using UCS 2 encoded text bodies, please use:
    <msisdn>@email2sms-ucs.websms.com or <msisdn>@email2sms-ucs.linkmobility.eu.

  • If you want to trigger a voice call by using the SMTP API, please use:
    <msisdn>@email2voice.websms.com or <msisdn>@email2voice.linkmobility.eu.

To send a message to the mobile number 436761234567 with your websms account, submit an email with the recipient address 436761234567@email2sms.websms.com. For the Linkmobility account, submit an email with the recipient address 436761234567@email2sms.linkmobility.eu.

The example number uses the international number format:

  • international prefix (eg. 43 for Austria)

  • the prefix of the mobile carrier (676 for T-Mobile-Austria)

  • and the mobile number itself.

Note: SMS messages terminated to a mobile phone are called MT (mobile terminated) whereas SMS messages send from a mobile phone are calles MO messages (mobile originated).

Authentication

Each user account is identified and authenticated by the e-mail address associated with the user account. The e-mail addresses used for authentication during account login must be set up in the account settings. To ensure that only the authorised sender can use the interface, the configuration on the gateway must be carried out by our customer service.

You can activate one or more IP addresses within the gateway for additional security.

Text format

Please use only plain text in your e-mail to submit your message. If you submit an HTML email body to our system, it automatically tries to identify the plain text containing it. If the system cannot recognise any text, it removes all HTML tags and uses the first 600 characters found in your message. Please ensure that you submit your text to the SMTP API properly.

The SMTP interface supports the following charsets

  • Latin I (ISO/IEC 8859-1)

  • UTF-8 (8Bit UCS transformation format)

  • UCS-2 (Universal Character Set – 2-bit)

Special Characters

If you use special characters, like the German (Ä, Ö, Ü, …), submit them hex encoded to ensure the correct display in Latin I:

  • Ä = C4hex / ä = E4hex,

  • Ö = D6hex / ö = F6hex,

  • Ü = DChex / ü = FChex

  • ß = DFhex

Content-Transfer-Encoding in your email header needs to be set to quoted-printable. Common email clients will submit the message correctly if HTML and Rich format are deactivated.

Concatenated SMS

SMS is limited to 160 characters, but with concatenated SMS, you can send up to 600 characters in a single text message transmission. Using this method, the message is split into smaller messages. If you stay below 160 characters, one SMS will be generated. If you surpass 160 characters, each segment will contain up to 153 characters.