How to avoid spam filters for text messaging

In research, efficient communication with study subjects via text messaging has become essential. However, dealing with mobile carrier spam filters is a significant challenge.

It's important to note that mobile carriers determine what constitutes spam. Even with explicit consent from study participants, research messages are subject to the same filtering standards. The following tips offer valuable insights to reduce the risk of messages being flagged as spam, but they cannot guarantee complete protection or prevent potential number blocking. Like email spam filters, mobile spam filters evolve as spammers adapt their tactics.

These guidelines aim to help researchers improve the deliverability of their messages, ensuring the smooth continuation of their projects. While these tips are useful, they do not guarantee that a message or number won’t be flagged as spam.

Make your text message content personal and conversational, not robotic. "Personal" does not mean including PHI, just making it more human-like. Text messaging is a conversation, even if your messages are one-way, so it's okay to use more conversational phrasing.

Include the name of the organization.

This really depends on your use case, but some clients put the name of the organization. Others use a project name. Both help show that there is an organization behind the messages being sent, one that can be looked up online.

Avoid ALL CAPS messaging, special characters and $ symbols.
Non-letters, number characters, etc that don’t look like two people communicating can kick off spam filters. ALL CAPS messages can as well, especially if they involve a call to action with some type of link.

Limit the number of links in your messages to 2 or less.
Use only one if you can.

Limit the use of popular URL shorteners. 
Spammers use bitly, tinyurl and other free link shortening services. While they can be useful, different types of content associated with them may cause issues. Mosio has its own proprietary link shortening system, which we encourage clients to use.

Unreasonably long links will also trigger spam filters.
Avoid sharing ones that look like: “https://www.google.com/maps/dir/35.047214,-85.303271/google+map+to+chili's/@35.0495358,-85.3111895,16z/data=!3m1!4b1!4m9!4m8!1m

Avoid sending multiple identical messages.
“Please take this survey.” is not only bland and provides no context for participants, sending it over and over again may make mobile carriers suspicious.

Send a welcome message on enrollment.
Encourage participants to save your texting number in their phone contacts.

If acceptable with your IRB, be sure to identify the study in the project name so participants know who it is when they receive a text!
Referencing the project name is a great way to help participants feel they are a part of something. Sending an initial welcome message with the project name, encouraging participants to add it to their phone contacts is a great way to initiate high engagement and keep adherence high throughout your communications.

Place your links in-between words. 
Surround your links with an explanation of where you’re sending the customer. That way both carriers and customers know you aren’t taking them somewhere dangerous.

Avoid sending “naked links”.
(link without the “https://www.”) Always include that first portion of your link to avoid triggering spam filters.  Mobile carriers care a lot about security and protecting their consumers, so we assume having “https://www.” shows that you link to a secured site and are less likely to be a spammer.

Limit your texts to 160 characters/segments (avoid lengthy text in general). 
We understand that longer messages can be useful to deliver helpful information. Mosio will concatenate messages accordingly. But use longer messages sparingly if you can.

Proofing your texts before you send them is a must.  
Atypical sentence structure, grammatical errors, and misspellings are the biggest indicator of spam. If your sentences are filled with typos, or sound like they were created by a wonky A.I., carriers will block you.

Offer a way to opt-out. 
Follow TCPA guidelines, and offer an easy opt-out (“text STOP to stop receiving these messages”) to avoid legal issues.

Register your 10-digit long code number (10DLC).
Mosio handles this for you so you can focus on your research. 

Send text to small lists. 
Avoid sending a text sent to thousands of subscribers.   Mobile carriers assume that the message is a “pray and spray” message. These types of messages are large, unsolicited advertisements, often detailing some type of coupon or other deal. To prevent the carrier from mistaking your message for spam, send content to small lists. 

Use custom fields.
When sending  templated messages to subscribers, use custom fields to make the message unique or personal to the receiver. This makes it read like a person sent it another person (P2P). Not only can this help a message not get marked as spam, it has the potential to be a better form of communication. 

We hope this has been helpful. When in doubt, always test before you go live, on multiple phones and with multiple mobile carriers if you can. Testing with your team can be a great way to test while going through the study participant experience as it relates to your communications.

Happy texting!