An SMS short code is a special 5- or 6-digit telephone number used for high-throughput commercial text messaging. Unlike regular 10-digit phone numbers, short codes are specifically provisioned for mass messaging and can send and receive thousands of messages per second — making them ideal for marketing campaigns, two-factor authentication, and high-volume alerts.
How Short Codes Work
Short codes are leased from the Common Short Code Administration (CSCA) in the United States and provisioned across all major carriers. When a business sends a marketing text from a short code, the message is carrier-approved and carrier-delivered at high throughput — unlike messages from regular phone numbers, which carriers may throttle or filter when sent at high volume.
Dedicated vs Shared Short Codes
Dedicated short codes are leased exclusively by a single organization. The brand has full control over the number and all messages sent from it. Dedicated short codes cost $500–$1,000/month to lease.
Shared short codes were previously common — multiple businesses sharing the same short code number, differentiated by keyword. In 2021, major US carriers began phasing out shared short codes due to compliance concerns. Dedicated short codes or 10-digit long codes (10DLC) are now the standard.
Common Short Code Use Cases
- Mass Marketing: Retail promotions, flash sales, loyalty programs sent to large subscriber lists
- Two-Factor Authentication: OTP delivery requiring high-speed, reliable delivery (banks, tech companies)
- Alerts and Notifications: High-volume operational alerts to large recipient bases
- Opt-In Campaigns: "Text SAVE to 12345 to receive offers" — short codes are memorable and easy to type
Short Codes vs 10DLC vs Toll-Free SMS
Short codes offer the highest throughput and are carrier-approved for marketing, but are expensive to provision and slow to set up (8–12 weeks). 10DLC (10-digit long codes) are regular US phone numbers registered for A2P (application-to-person) messaging — lower cost, faster setup, suitable for most business messaging. Toll-free SMS uses toll-free numbers (800, 888, etc.) registered for text messaging — a middle ground in cost and throughput.
For most organizations using on-premises SMS software like PageGate, 10DLC numbers or direct carrier connections (via SMPP or GSM modem) are more practical than managing short code leases.
