Why it matters
Phone carriers use filtering systems to protect subscribers from unwanted or harmful content. Messages that appear spam-like, overly promotional, or non-compliant may be blocked before reaching recipients. Writing clear, compliant messages helps maximize delivery rates and reduce the risk of future carrier blocks.
Key Concepts
Carrier filtering: The process carriers use to block messages that resemble spam or violate content rules.
Opt-in: Consent from recipients confirming they agree to receive SMS communication.
Opt-out: A clear way for recipients to stop receiving messages, often required by carriers.
Message segments: SMS messages split into 160-character parts; longer messages increase filtering risk.
Step-by-Step: Write Messages That Avoid Carrier Filtering
Identify yourself in the first message.
Use a simple introduction such as “Hey, this is Ty from Whippy.” Only include this in your initial message.
Use clear and concise copy.
Keep messages short.
Use a friendly, natural tone.
Avoid excessive CAPITAL letters.
Limit symbols, exclamation points, and emojis.
Avoid spam-like, unwanted, or prohibited content.
Do not include:
Promotional phrases like “BUY NOW” or “SIGN UP FREE”
High-volume outreach to contacts without prior messaging
Repetitive or identical messages to many recipients
References to cannabis, prescription drugs, or restricted items
Fraudulent, abusive, or harmful content (malware, hate speech, harassment)
Include opt-out instructions.
In your first message, add “Reply STOP to unsubscribe” or similar opt-out language.
Only message contacts who have consented.
Ensure recipients have explicitly agreed to receive messages. Keep records such as form submissions or signup timestamps.
Keep messages short to reduce filtering risk.
Messages longer than 3 segments (approximately 480 characters) are more likely to be filtered, especially for recipients using smaller carriers.
Tips and Best Practices
Customize and personalize your copy to build trust with recipients.
Avoid sending the same message repeatedly across large lists.
Keep opt-in and opt-out processes clear and documented.
Review existing campaigns for overly long or repetitive content.
Rework messages flagged for spam before attempting to resend.
Troubleshooting
Issue | Possible Cause | Fix |
Messages repeatedly filtered | Number flagged for spam or content too promotional | Shorten and rewrite message; remove risky language |
Delivery delays for long messages | SMS segments too long | Reduce message length below 480 characters |
Contacts report not receiving messages | No prior consent or carrier filtering | Confirm opt-in status and adjust copy |
Messages flagged after following best practices | Number already marked by carrier | Contact Whippy Support for carrier review |
Important Note
Once a phone carrier flags your number for spam, future messages are more likely to be filtered; even if they follow best practices. If this occurs, contact Whippy Support for assistance in working with carriers to remove spam blocks.