websms SMTP API

Use the websms SMTP API to access to websms using your email system.

Available channels


Voice messages

Push messages

Interface call

The SMTP API – like all our services or development tools – runs on a websms.com domain no matter which country you are from.
The syntax contains the recipient mobile number (msisdn), for instance: <msisdn>@email2sms.websms.com (e.g. 436761234567@email2sms.websms.com)

To send a message to the mobile number 436761234567 submit an email with the recipient address 436761234567@email2sms.websms.com. The example number uses the internation number format:

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).


Each websms user account is identified and authenticated by the email-address related to the user account. The email addrees used for authentification at the websms AccountLogin has to be set up in the account settings. To ensure only the authorised cliend can use the interface, the configuration has to be done at the websms gateway by our customer service.
Additionally you use the email subject for authorization. Use the AccountLogin (Example: Subject: SMSGW-Auth: example@customer.com). To avoid fraud, the websms SMTP API has to be set up in your account settings. Additionally the subject contain a combination of AccountLogin and AccountPass, seperated by “:” (Example: Subject: SMSGW-Auth: example@customer.com:mypass)
websms customers can enable one or more IP-addresses within at the websms gateway for additonal security.

Text format

Please us only plain text in your e-mail for submitting your messge. If you submit a HTML email body to our system it automatically tries to identify the containing plain text. If no text can be recongized the system cuts all HTML tags your text and uses the first 600 characters found for your message. So please take care how you submit your text to the SMTP API.
The websms SMTP interface supports the following charsets:

If you use special characters, like the German (Ä, Ö, Ü, …) submit them hex encoded to ensure the correct dispaly in Latin I (Ä = C4hex, ä = E4hex, Ö = D6hex, ö = F6hex, Ü = DChex, ü = FChex und ß = DFhex). Content-Transfer-Encoding in your email header needs to be set a quoted-printable. Common email clients will submit the message in the correct way if HTML and Rich format is deactivated.

Concatenated SMS

SMS are basicly limited to 160 characters, but wich concatenated SMS you’re able to send up to 600 characters in a single text message transmission. Using this method, the message is split into smaller messages. As long as you stay below 160 characters, one SMS will be generated. If you surpass 160 characters each segment will contain up to 153 characters.