Short Codes or Long Codes? Benefits and Drawbacks for your SMS Campaigns


Choosing the right tool for the job is always a good idea and the time you invest in evaluating benefits, risks, and limitations of each one of those tools always pays off in the end.

In this post we’re going to take a look at two different ways of sending your Transactional and Promotional SMS: Long Codes and Short Codes.

Note that using short codes is still the preferred way for sending SMS’ to a large number of users. Now, if you are using long codes (aka DIDs) for some of your local (or international) mobile SMS campaigns, you will notice that there are some limitations and risks involved. Let’s see the pros and cons of both options.


Long codes are cheaper, and short codes are a bit more expensive.


Long codes are owned by only one client, so they can be used entirely for inbound and outbound messages at will.

Short codes on the other hand are shared (most of the time) and to differentiate owners, applications, and services “running on that short code”, keywords need to be used (i.e: your clients/users interact with your short code by specifying a keyword, like “DEALS”).

This means that using A2P on a short code is usually a better choice, because there are no special keywords that your clients need to send to that short code, except for the “A2P language” that your application accepts. This traffic is also “transactional”, and this means that having both inbound and outbound messages will greatly reduce the chances of being reported as SPAM or blocked by a carrier.

Local and International Audiences

Long codes can be used to reach your customers worldwide, while short codes are only useful for a specific country.

You would need to get a short code for each country where you would like to send bulk messages to. Long codes are regular telephone numbers so they can be used to send messages to the entire planet.

Regulations: Subscriptions, Opt-in and Opt-out

There are strict laws that impose severe penalties to parties that send unsolicited messages to people, and that’s why mobile marketing has to comply with some regulations.

For example, you can’t send a message to a person unless that person gave his or her prior written consent.

Short codes come with a set of requirements that govern how people can voluntarily opt-in and opt-out to your service by using plain SMS (this is called “Permission Marketing“), and we can automatically handle everything needed to manage your SMS subscriptions by ourselves so you don’t have to.

Short codes are requested with this intend in mind, so when requesting a short code there is some information that carriers need to approve first before letting your traffic flow, and this includes a sample of your content, the terms and conditions of your service, and the description of what your service provides and how users can subscribe and unsubscribe from it.

Note that we also offer a way for your users to opt-out of your SMS messages when they are sent from a long code.

Throughput: The 1 SMS Per Second Limit

In the US, carriers impose a limit rate of 1 message per second for long codes, as a way to protect themselves from abusive SMS grey routes, and also from people that tend to send unsolicited SMS to mobile phones. Our systems handle and honor this limitation automatically when you send messages from a long code.

Short codes don’t have this limitation, although you can’t use them for international destinations.

This means that when sending a lot of messages, short codes will behave better than long codes (i.e: you can send many more messages in a given time by using short codes).

SMS SPAM protection

Carriers also have sophisticated SMS SPAM detection algorithms that can automatically trigger alarms and even temporarily block numbers with suspicious activity. These do not apply to short codes because your content and type of use was already approved, and also your users have voluntarily opted-in (somehow) to your messages.

Note that having a lot of inbound messages to your numbers can greatly reduce the risk of being blocked, sued, and/or the termination of your service, so make sure that your content is either Transactional or represents an interest to your users.

Toll Frees and Using multiple long codes to balance the traffic

Toll frees seem to have the advantage of having a bit more relaxed restrictions. In the end, you could use a bunch of toll frees and local numbers to deliver your messages, balancing the traffic between them to help reduce the risk of being blocked by carriers.

When creating an SMS campaign, you have the option of specifying multiple long codes as the origin, so your traffic will be balanced and distributed across all of them.

Don’t forget to read about Best Practices for your SMS Campaigns and how to actually run marketing campaigns with good karma to get the most out of your SMS messages.

If you have any questions, please don’t hesitate to contact us, we’re always looking for ways to give the best possible SMS experience to our customers. Until the next time 🙂

— The PortaText Team.