SMS Best Practices to Avoid Being Blocked SMS Best Practices to Avoid Being Blocked

SMS Best Practices to Avoid Being Blocked

Jasper Jasper


While Kixie will always send your SMS messages to their destination, it's possible that the recipient's mobile phone carrier i.e. AT&T/Verizon may block delivery of the SMS message due to a number of factors related to the SMS message itself, which of course is completely beyond Kixie's control. 

Overall Best Practices to Avoid SMS Messages Being Blocked by Receiving Carriers:

  • Keep your messages short and conversational, and avoid lengthy/marketing-heavy messages. This especially applies to your first-ever SMS message to someone.
  • The first-ever message to the prospect's number ideally should be a conversational introduction like "Hi [firstname]". Then, delay for at least a few seconds, and send the remainder of your text, and then send whatever un-shortened link you want to send (so 3 total messages). This is easiest to accomplish with auto-SMS via Zapier or directly from a HubSpot workflow, which of course also has the benefit of standardization and automation, so you don't have to trust your reps to remember to send the text the right way.
    • The initial "Hi [firstname]" text increases the chances of subsequent messages being allowed through by the mobile carrier, especially if you plan on sending a link afterwards. And again - never use shortened links like or tinyurl.

The Main Reasons an SMS Message Would be Blocked by a Recipient's Mobile Phone/Carrier:

  • The message contains a URL (especially a shortened link such as or tinyurl)
    • If you're going to use a URL, it is worse if it is a repetitive URL(s), and worse still if it is a shortened link (such as
      • repetitive url example:
  • The same message has been sent repeatedly - without variation or personalization 
    • workaround - use [fname] in your SMS template to personalize it automatically, or use the rep's first name in your auto-sms via Zapier.
  • More than 200 SMS/day are sent per SMS number
    • workaround - call more, text less!
  • Long texts
  • The receiving mobile device blocks unknown SMS numbers as a rule
    • perhaps the user downloaded an anti-spam app
      • perhaps the mobile device may also send SMS messages from numbers for which there has never been a phone call in the past, right to spam
        • workaround - call your prospect's number before texting them
  • Your number was manually reported as spam to a carrier(s).
    • workaround - you can easily replace any agent's DID/SMS DID with a new one anytime which will fix this issue.
  • The ratio of incoming to outgoing SMS on an SMS Number is more than 1:3
  • The same message is sent from the same number within 5-10 seconds of the first message

Please email or reach out to your Account Manager for help crafting the most deliverable auto-SMS and/or SMS templates for your team, we're always happy to help!