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Using Keywords with VMNs and Shortcodes (Part 1)

keywords vmns and shortcodes

The use of keywords for SMS marketing was an amazing idea. I haven’t been able to find who used them first, but they are now an indispensable part of any SMS marketing campaign. Using them simplifies the communication between businesses and their customers: All a customer has to do is type in a word and hit send.  That makes it super easy for them.

But you need to use two-way messaging if you want to have keywords in your marketing. This means you’ll have to have either a virtual mobile number (VMN) or access to a shortcode. While conceptually keywords work the same on either one, there are some small differences. So, before you decide which one you want to use for your next marketing campaign, take a moment to read about them.


A shortcode is a short combination of numbers used instead of a traditional mobile number. They are considered easier to remember, and trendier too, than a VMN. But the important thing about them is that they come in two types: dedicated and shared.

Dedicated means the shortcode belongs to just one organisation. A shared shortcode can be used for multiple businesses at one time. While having something just for your business sounds great, a dedicated shortcode is too expensive for most organisations. And a shared shortcode can work just as well.

The only real difference when it comes to using keywords with shortcodes is availability. If you have a dedicated shortcode, you can choose any keyword you want. But that option comes with a bill that’s likely over £10,000 per year, not counting the cost of the messages you send.

If you’re budget is less than that, you can rent keywords on your SMS provider’s shortcode. At fastsms, our keywords are just £25 per month (or £250 per year). You can rent your keywords for as long as you need them, which makes it an affordable option. For example, let’s say you choose the keyword “HOME” for your opt-in campaign. You run the campaign for two months and you get 1,000 subscribers (just to keep the maths easy). The total cost for the campaign would be the £50 for the keyword “HOME”, and £35 for the confirmation messages sent to the 1,000 who opted in. The grand total is £85.

You’d have paid the £35 for messages no matter what, even with a dedicated shortcode. So, using shared shortcodes is much less expensive, even counting the rental of keywords. Of course, if you wanted to keep the keyword for a longer period, or you had more opt-ins, the cost would change.

At this point, you may be wondering what the downside to a shared shortcode is. It isn’t cost, obviously. The fact that it is shared means that keywords can only be used by one organisation. If my business used “HOME” at the same time as yours, on the same shared shortcode, who knows where the messages would go. Maybe we’d both get them and we’d be in quite a fix.

Reputable SMS providers ensure that keywords on their shared shortcodes are only used by one customer at a time. And they tell you before you pay for them.  For example, fastsms has a keyword order form in our platform. It automatically checks to see if the keyword is available before you make your final order. Our software then sends any messages with that keyword to your account so there’s never any confusion.

Some of our competitors claim you need a dedicated shortcode for SMS marketing with keywords. What I’ve described above shows that isn’t true. Shared shortcodes make it affordable for everyone, but dedicated ones are available for those that need them.


Think of a VMN as a dedicated shortcode, only longer. At least when it comes to using keywords. These numbers are assigned to just one account at a time, so you’re free to choose whatever keywords you want. There are no restrictions.

This gives you total freedom when designing your marketing campaigns, at a much lower cost than with a dedicated shortcode. The current rate for a VMN with fastsms is £99 per year. That’s it. There are no additional fees for keywords.

The downside, if it actually is one, is that the 11-digit VMN isn’t as easy to remember as a 5 digit shortcode. Over the years, I’ve searched for some empirical data to prove the value of one over the other. I’ve yet to find anything conclusive. The truth is keywords work with both kinds of numbers. Which one will work best for your business may be determined by your budget, or maybe you’ll want to experiment to find out.

Now that you know all about needing a two-way message service for using keywords, you’ll probably want to get started. But how do you pick your keywords? You may be surprised. Be sure to read Part 2 to see three guidelines about choosing keywords.

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