A short code is a 5-digit or 6-digit address used to send and receive SMS and MMS at high volume. In the United States, common short codes are leased (not owned like a DID) through the industry short-code program and provisioned onto each participating wireless carrier. They exist to give A2P a dedicated, easily typed destination (for example a vanity 6-digit code) with operator-grade throughput.
Provisioning has historically taken 8 to 12 weeks: the lease is approved, then each MNO reviews the program (use case, samples, opt-in, STOP) and adds the code to its SMSC routing tables. That lead time is why 10-digit long codes and 10DLC became the default for most US A2P, and why short codes remain the path when a program needs MNO-level throughput or a very short dialable code.
Dedicated, shared, random, vanity
- Dedicated short code
- One brand, one program (or a tightly related set). The standard form for sustained A2P programs. Monthly lease plus aggregator and carrier fees.
- Shared short code
- Multiple brands behind one code, often with keyword routing. Carriers have restricted or disallowed shared codes for mixed A2P because one abusive sender damages deliverability for every brand on the code.
- Random vs vanity
- Random digits are cheaper and faster to obtain. Vanity codes spell a word on the keypad and are scarce. Networks route digits, not letters.
Short code vs 10DLC vs toll-free vs RCS
| Path | Address | Lead time (typical, US) | Throughput | Registry |
|---|---|---|---|---|
| Short code | 5- or 6-digit | 8-12 weeks historically (per-MNO review) | High (operator SMSC class; often tens to hundreds of messages per second depending on the lease) | Short-code administration + each MNO, not TCR 10DLC |
| 10DLC | 10-digit local number | Days to a few weeks including vetting and any MNO campaign review | Set by brand vetting and campaign class (T-Mobile daily cap, AT&T TPM) | TCR brand + campaign |
| Toll-free texting | 8XX | On the order of days to a couple of weeks for verification | Carrier-verified 8XX class (often quoted around tens of MPS once verified) | Toll-free verification, not 10DLC |
| RCS Business Messaging | RCS agent / brand | Depends on RBM onboarding and device support | Not SMSC segment math; requires RCS-capable clients | GSMA / Google RBM paths |
CTIA Messaging Principles still apply: consent, sender ID, STOP/HELP on promotional programs, SHAFT restrictions. A short code that is live on AT&T, T-Mobile, and Verizon can still fail on a smaller MNO if that operator never provisioned the code. Coverage has to be confirmed carrier by carrier; it is not a property of the 5-digit string.