A short code is a five- or six-digit phone number used to send and receive business text and multimedia messages at high volume. In the US, short codes are leased through a common registry administered for the wireless industry, and each messaging program must be approved by the mobile carriers before it goes live. Businesses use them for one-time passcodes, alerts, marketing campaigns and “text KEYWORD to 12345” programs. Short codes generally offer the highest sending throughput of the US business texting options, but they take longer to set up and cost more than 10-digit or toll-free numbers.
At a glance
- Short codes are five or six digits and are used only for messaging, not voice calls.
- In the US, codes are leased for a set term and each program is reviewed and approved by the mobile carriers.
- They typically support much higher sending speeds than 10DLC or toll-free texting.
- Vanity codes (chosen by you) cost more than random codes (assigned to you).
- Short codes are national; other countries run their own programs with their own rules.
What problem it solves
Businesses sending texts in bulk, such as login passcodes, fraud alerts, delivery updates or promotions, need those messages delivered quickly and reliably. Sending large volumes from ordinary phone numbers looks like spam to carriers and is likely to be throttled or filtered.
A short code is a sanctioned channel built for that volume. Because carriers review and approve each program in advance, approved short code traffic is generally treated as trusted and allowed to send at high rates. A short, memorable number also suits campaigns where customers text in a keyword to join a list or enter a promotion.
How it works
Leasing. In the US, short codes are leased through the industry’s common short code registry, usually with the help of a messaging provider or CPaaS platform. Leases run for set terms and are renewed; letting a lease lapse can mean losing the code.
Program approval. The business submits a description of its messaging program: who it is, what messages it will send, how people opt in, how they opt out and how often messages go out. The provider submits it to each mobile carrier for review. Carriers can ask for changes, and approval is required before traffic flows on their networks.
Throughput. Once live, short codes typically support far higher sending rates than 10DLC or toll-free messaging, which suits time-sensitive bulk messaging.
Keywords and compliance. Programs must handle standard keywords, such as STOP to opt out and HELP for information, and follow carrier messaging guidelines. Carriers audit programs and can suspend those that drift from what was approved. In the US, the Telephone Consumer Protection Act (TCPA) and state laws can also apply; check with counsel.
Messaging types. Short codes carry SMS and, where enabled, MMS. Many platforms pair them with RCS or other channels.
For choosing a messaging platform and sender types, see our communications platform as a service solution page.
When it matters for buyers
- High-volume or time-sensitive messaging. Passcodes, fraud alerts and large broadcasts are where short codes earn their cost.
- Keyword campaigns. Marketing that asks customers to text a word to a number benefits from a short, memorable code.
- Choosing between sender types. For lower volumes or conversational messaging, 10DLC or toll-free numbers may be quicker and cheaper.
- Launch planning. Carrier approval time should be built into campaign and product launch schedules.
- Changing providers. Confirm the short code lease is in your name, or can be transferred, so you keep the number.
Questions to ask vendors
- Will the short code lease be in our name, and can we take it with us if we change providers?
- How long does carrier approval typically take for our use case, and who manages the application?
- What throughput will we get, and what happens if we exceed it?
- Is MMS supported on the short code, and with which carriers?
- How do you handle opt-in records, STOP and HELP keywords, and carrier audits?
- What are the lease, setup and per-message costs, including carrier surcharges?
How it differs from 10DLC
Short codes and 10DLC are both registered routes for business texting in the US. 10DLC uses ordinary 10-digit local numbers that can also take voice calls, registers the brand and campaign through a central registry, and suits conversational and moderate-volume messaging. A short code is a dedicated five- or six-digit messaging number with per-program carrier approval, higher cost and higher throughput. Many businesses use both: short codes for bulk alerts and 10DLC for two-way conversations from local numbers.