A short code is a five- or six-digit number that businesses and organizations use to send and receive text messages, and a common short code works across all the participating U.S. carriers rather than on one network only. Five-digit codes fall between 20000 and 99999, six-digit ones between 200000 and 999999. They work only inside the United States; Canada keeps a registry of its own.
Who runs it
The registry is the Common Short Code Administration, usually shortened to CSCA and found at usshortcodes.com. CTIA, the trade association of the U.S. wireless industry, owns the program and writes its rules. The database itself has been operated by a contractor since the program started in 2003. Neustar held that job for the first twelve years. After a competitive tender, CTIA chose iconectiv as its new registry partner, and iconectiv has run the service since January 1, 2016.
What it does
The registry keeps the single list of codes that are available, reserved and registered, and assigns them on a first-come, first-served basis. A code that someone else holds stays unavailable until that lease ends or is terminated. Its main functions:
- leasing codes, at $500 a month for a random number or $1,000 for a chosen one, on three, six or twelve month terms
- a public search for free numbers, with filters for words spelled on the keypad and easy patterns such as repeating pairs
- the campaign record for each code, which carriers and CTIA’s monitoring team check the live program against
- a list of partners, such as aggregators and application providers, that help put a code into service
What it does not do is switch a code on. A leased number carries nothing until each carrier has reviewed and provisioned the campaign, a step handled through an aggregator, and every carrier decides for itself whether to support a given code.
How a text reaches the right company
The registry is also what makes a common code common. When a subscriber sends a keyword to, say, a five-digit number printed on a cereal box, the message goes first to the messaging server of that subscriber’s own carrier. The server looks up which application provider the code belongs to and hands the message over. The provider’s software reads the keyword, decides what the program should do with it and sends the reply back along the same path. Because every carrier routes the code to the same place, one number printed in one advertisement works for customers of all of them, instead of a brand needing a separate code per network as it would with a carrier-specific one.
For the person receiving the texts
Every short code on a U.S. carrier traces back to a lease held by a named company on the registry’s books. The registry’s own advice to anyone with a question about a code is to contact the company promoting it, or to text HELP to the number, which under CTIA’s rules has to return the program’s name and a way to reach it.
Since then, CTIA has handed the registry to another contractor: GCH Technologies took over on January 1, 2026, and the site now goes by the name Short Code Registry.