By default SMS.to generates secure API keys. These consist of more characters and are the suggested method to use our API with all 3rd party software. 

Some 3rd party tools, however, are known to be unable to handle such long keys. If the integration does not work or you receive an "invalid API key response" after integrating, try to generate a short API key by unselecting the secure option when generating the API key. 

If you have any questions, please send an email to support@sms.to