Long Code

A long code is a standard 10-digit phone number used by businesses for sending and receiving SMS or MMS messages. When properly registered, long codes support personalized, compliant messaging at scale - especially for customer service or ongoing conversations.

Why long code matters

Long codes allow businesses to message customers using familiar, local-looking numbers. These numbers are ideal for two-way conversations, appointment reminders, and personalized updates. When paired with the right platform, long codes can scale to thousands of messages per day while staying compliant with industry regulations.

Unlike short codes, long codes support both messaging and voice, making them more versatile for companies looking to unify communication channels. They also allow businesses to use their existing phone numbers, making the transition to SMS easier and more cost-effective.

For businesses using platforms like Clerk Chat, long codes can be enabled quickly, and fully integrated into tools like Slack, Microsoft Teams, and CRM systems - without sacrificing reliability or compliance.

How long code works

Here’s how long code messaging works in a business context:

1. Number provisioning – Businesses use an existing 10-digit number or lease a new one through a provider.
2. 10DLC registration – In the US, long codes must be registered with carriers to qualify for business messaging.
3. Platform connection – The number is linked to a messaging platform like Clerk Chat via BYOC or native integration.
4. Messaging setup – Compliance settings like opt-in, opt-out, and volume limits are configured.
5. Send & receive – Businesses can begin sending texts and receiving replies, often within seconds.
6. Monitor results – Deliverability, replies, and opt-out rates are tracked to optimize messaging quality.

Proper setup ensures delivery, avoids spam filters, and keeps your SMS campaigns legal and effective.

Best practices with long code

• Register your long code for 10DLC - This is mandatory for A2P messaging in the US.

• Use your existing number for continuity - Keep your business number and add texting without confusion.

• Segment traffic types - Avoid mixing support, marketing, and alerts on the same number if possible.

• Set opt-out keywords - Always honor STOP, CANCEL, or other unsubscribe requests automatically.

• Avoid sending too fast - Respect carrier throughput limits to avoid message throttling or filtering.

• Enable MMS if needed - Use media where relevant - images or PDFs can boost engagement.

• Monitor delivery and response metrics - Use analytics to optimize timing, content, and targeting.

Real world examples

Common misconceptions

Related terms