What is Carrier Filtering?

Carrier filtering is the automated process by which mobile carriers (AT&T, T-Mobile, Verizon) scan and filter incoming SMS messages to protect consumers from spam and fraudulent content.

How Carrier Filtering Works

1. Content analysis: Scans for spam triggers

2. Pattern matching: Identifies suspicious sending patterns

3. Sender reputation: Checks sender trust scores

4. Volume analysis: Monitors unusual sending spikes

5. Recipient feedback: Incorporates spam reports

Common Filtering Triggers

Content-based triggers:

Spam keywords (FREE, WINNER, ACT NOW)

Suspicious URLs

Excessive capitalization

Unusual character patterns

Prohibited content

Behavior-based triggers:

High message volume

Low engagement rates

High opt-out rates

Unregistered numbers

Repeated content

Consequences of Filtering

Soft filter: Message delayed or deprioritized

Hard filter: Message blocked entirely

Number flagged: Reduced throughput

Number suspended: Complete blocking

Avoiding Filters

1. Register your numbers (10DLC)

2. Use clean, natural content

3. Maintain healthy opt-out rates (<5%)

4. Segment and personalize

5. Follow carrier guidelines