What is Carrier Filtering?
Carriers expect that all texting behaviour is done by a human interacting with a standard texting interface (think about how you actually text using your phone or using iMessage on your desktop). Filtering happens when a carrier prevents an outgoing message from being delivered to your recipient.
How is Carrier Filtering Controlled?
Filtering is determined by your text recipient’s specific carrier. Mobile carriers are not forthcoming about their filtering criteria but are ultimately looking for messages that they deem to be "non-human” in nature. They consider what normal human texting behaviour looks like and have published suggested guidelines (these are not hard and fast rules but are meant to give us an idea of what carriers consider in designing their filtering technology):
The number of messages sent from your phone number during a certain time period (humans cannot send more than one message per second. They likely also consider the length of messages in conjunction with the speed at which they are sent). Sense helps you with this by spacing out Broadcasts and Engage SMS Messages.
The similarity of messages that have been sent to the carrier’s network from your number (a good rule of thumb is 25 repetitive messages).
Messages containing spam-like content (links, email addresses, and special characters)
The ratio of outbound to inbound messages. Carriers are less likely to flag your number if your conversations indicate a back and forth between you and your recipients.
Sense and Carrier Filtering:
Sense does a number of things behind the scenes to prevent your phone numbers and messages from being carrier filtered but these are easy steps you can do as well (Sense updates these as we receive more information about carrier filtering).
Note: these requirements are not set in stone but are general rules of thumb and best practices to be conservative with your SMS traffic
Keep in mind:
Message length: keep your messages under 140 characters, 1-3 sentences max, and try to avoid line breaks
Target audience (narrow down your audience to cater to your recipients)
Always include context around the scheduling link so recipients understand what you’re sending them
Recommended: Use variables in broadcast messages. This diversifies message content.
Avoid the following:
Using links when possible, especially on large broadcasts
Make sure not to include the URL link at the end of a long message as it may be broken into segments if the number of characters for that message is crossed
Special characters (especially the $ sign)
Multiple punctuation marks (multiple exclamations are scary!!!!)
Using all caps (THIS IS ALSO SCARY)
Use multiple broadcasts--especially for larger audiences
Schedule broadcasts to send throughout the day/week
Use variables and different phrasing in your messages
Ask for a reply in your message (this will ensure you maintain a good ratio)
Check your messaging stats on a regular basis to ensure you have a good response rate
If you notice lots of candidates opting out of your broadcast, reach out to your CSM to diagnose your message and give recommendations on how to improve the quality of your outbound texts
One simple to implement the strategy is to break up broadcasts into multiple sends so they vary in content and timing. For example, if you’re looking to fill a role for java developers, you can break up one message into multiple broadcasts based on job location & experience level:
New York Java Developers (Scheduled to send at 8:17 am on Tuesday)
Hi <contact_first_name>, we’re looking to fill a few java developer positions in NYC. Let me know if you’d like to chat more about them and hope you have a great day 😀
San Francisco Java Developers (Scheduled to send at 10:09 am on Friday)
Hi <contact_first_name> and happy Friday 🙌 I have a few Java Developer opportunities in SF. Let me know if you’re interested and we can coordinate a time to chat more
Senior San Francisco Java Developers (Scheduled to send at 4:40 pm on Monday):
Hey <contact_first_name>, hope you’re doing well! We have a few companies in the city looking for Senior Java Developers and you came to mind. Are you interested?
Notes about the above:
The character count is below 160 for all of these (considering that the average first name length is 6 characters). The exact message may differ from recipient to recipient depending on the length of the person’s name
They all ask for a reply from the recipient (helps boost your response rate)
Verbiage is slightly different among them all but still gets the message across
Scheduled throughout the day and week
Emojis - personal and fun similar to how a human would text
Why am I being carrier filtered?
- Issues with the recipient number
- The recipient number is inactive
- The recipient number is connected to a landline phone which is not SMS enabled.
- The recipient’s phone is powered off or disconnected from the network.
- The recipient’s phone does not have a sufficient signal.
- The recipient’s phone is roaming and not enabled to receive SMS while roaming.
- The user has opted out of receiving messages from this number. Try asking them to type START.
- The destination user has a wireless plan that does not support short code or "Premium" messages. They will need to contact their service provider to enable receiving messages from your number.
- The recipient has put themselves on a “Do Not Disturb” or “Do Not Call” list that blocks all unknown senders. To receive your messages, your number will need to be saved as a contact in their phone.
- The recipient is not able to receive your SMS due to a specific configuration on their mobile phone service plan. They will need to contact their service provider to have your number added.
Your phone number is being carrier filtered:
- The number you are sending from has received previous spam complaints from recipients.
- A higher than average number of recipients are opting out of messages from this phone number.
- The receiving carrier has blocked the message for violating their rules or policies.
- Even if this message is 1:1, it is possible the carrier has blocked your phone number for previous outbound traffic violations.