Best Practices to Avoid Carrier SMS Filtering

SMS compliance is the set of legal and carrier rules you must follow for your text messages to reach recipients. Following these rules is the most reliable way to stay off carrier spam filters and protect your sending reputation.

This article covers the practices that keep your account compliant, how to confirm you are meeting them, and what happens if you fall out of compliance.

What does SMS compliance mean?

SMS compliance is the set of legal and carrier requirements that govern how businesses send text messages. It covers two layers: legal rules (TCPA, CTIA messaging principles) and carrier rules (A2P 10DLC registration, content standards, sending behavior).

Compliance is what prevents filtering, not just what fixes it. Carriers run automated systems that score every message in real time on content, sending pattern, and registration status. Compliant senders earn higher trust scores and better delivery. Non-compliant senders get filtered, throttled, or blocked.

Best practices to avoid carrier SMS filtering

Following these practices keeps your messages out of the filter queue. Most filtering issues trace back to one of these compliance gaps.

Register your number through A2P 10DLC

A2P 10DLC is the registration standard for businesses sending application-to-person messages over a 10-digit local number. Carriers require this registration before you send at volume.

Registration covers two pieces:

Brand registration: your legal business name, EIN, and address
Campaign registration: your use case (reminders, alerts, marketing) and sample messages

Text-Em-All handles 10DLC registration at no extra charge. Most registrations are complete within one to two business days.

Every contact on your list must give you express written consent before you can text them. Acceptable consent methods include signed paper forms, web form checkboxes with clear disclosure, and keyword opt-ins.

What does not count as consent:

Purchased contact lists
Scraped or harvested phone numbers
Existing customer relationships without a separate SMS opt-in
Implied or assumed consent

Carriers and the TCPA both require consent records you can produce on request. Store the date, source, and language of every opt-in.

Match consent type to message type

SMS rules recognize two consent tiers. Informational messages like reminders, alerts, and updates require express consent. Promotional messages require express written consent.

Sending a promotional offer to a list collected for operational alerts is a TCPA exposure and a deliverability risk. Keep your campaigns separated by message type, and collect the right consent tier for each.

Honor opt-outs automatically

Carriers expect you to remove anyone who replies STOP, QUIT, CANCEL, UNSUBSCRIBE, or similar opt-out keywords. Failure to honor opt-outs damages your sender reputation and exposes you to TCPA penalties.

Text-Em-All processes opt-outs automatically and removes the contact from all future campaigns. Your opt-out report shows every removed contact and the reason.

Identify your sender in every message

Recipients who do not immediately recognize the sender opt out. High opt-out rates damage sender reputation.

Start every message with your organization's name. "Grove Medical:" or "Ridgeline Staffing:" at the opening tells the recipient who they are hearing from before they decide whether to read on.

For the first message in any promotional sequence, include opt-out instructions. "Reply STOP to opt out" at the end of the message is standard and required.

Send only within legal time windows

The TCPA requires SMS messages to be delivered between 8 a.m. and 9 p.m. in the recipient's local time zone. Sending outside this window is a federal violation.

Out-of-window sends also generate complaints that compound your filtering risk. Recipients who get a text at 6 a.m. are likely to opt out, and the opt-out signal hurts every future send.

Match content to your registered use case

Your registered campaign is a promise to carriers about what your traffic looks like. Sending content that does not match the registered use case can trigger filtering.

Examples of mismatched content:

A campaign registered for appointment reminders that starts sending promotional codes
A campaign registered for employee alerts that adds marketing offers
A new product line introduced without updating the registration

Update your campaign registration before you expand into a new use case.

Avoid prohibited content categories

Carriers restrict or ban some content categories regardless of consent. The most common restrictions cover SHAFT content (sex, hate, alcohol, firearms, tobacco). Carriers also restrict high-risk financial offers like payday loans, credit repair, and debt forgiveness.

Age-gated content like alcohol and tobacco requires explicit age verification on opt-in. Carriers also ban content that misrepresents the sender or destination. The Text-Em-All no spam policy lists the full set of restricted use cases.

Use clean, branded URLs

Carriers weigh generic link shorteners as high risk because spam senders use them heavily. Avoid bit.ly, tinyurl, and similar public shorteners.

Better URL practices:

Use a branded short link tied to your domain
Include the full URL when length allows
Place links at the end of the message, not embedded mid-sentence

How to confirm your account is compliant

Run through this checklist before any large send. Most compliance gaps show up in one of these checks.

Confirm registration status. Both your 10DLC brand and campaign should be registered and active.
Review your opt-out rate per campaign. Target under 1%. Investigate any campaign that runs higher.
Audit a recent message. Check for sender identification, opt-out language, and alignment with the registered use case.
Confirm consent collection is documented. Your privacy policy, opt-in mechanism, and storage method should all be on file.
Verify your sending hours. Check the recipient’s time zone for every campaign, not just the sender's.

Reach out to Text-Em-All support if you need help confirming any of the above.

What happens if you fall out of compliance?

The consequences range from minor delivery issues to legal exposure.

Carrier-level consequences:

Filtering of individual messages
Throttling of your sending speed
Full block of a sending number
Campaign suspension by The Campaign Registry

Legal consequences:

TCPA private right of action ($500 to $1,500 per message)
State-level consumer protection claims
Class-action exposure for repeat violations

If filtering has already started, walk through the common causes of carrier SMS filtering to identify which compliance gap is in play. Other delivery problems, like bad numbers or recipient-level blocks, fall outside compliance and have a separate troubleshooting flow.