SMS short code or long code: Which one to choose?
If you’re planning to let customers reply to your SMS messages, the type of number you choose makes a big difference. In the UK, your two main options are short codes and long codes. They both work, but they offer very different experiences for you and your customers.
Short codes are fast & recognisable, but for specific use
A short code is a 5-digit number that comes with a keyword. It’s designed for large-scale messaging and are instantly recognisable as business numbers.
Short codes are great if you need keyword-driven responses. We have a shared shortcode (88440), where you choose a unique keyword on this for your business. For example, you often see recruitment campaigns with posters or billboards saying things like ‘Text APPLY to 88440’.
What are SMS short codes used for?
Short codes are often useful for competitions or voting, allowing the public to easily text in for thousands of replies in a short time.
Another common use case is data capture at scale, such as surveys with one-word answers that trigger an auto-response upon texting in.
Can my short code be unique?
While it’s possible to get a unique short code for a brand, this isn’t something businesses tend to opt for, as it can cost a lot. Last time we checked, dedicated shorts cost about £800 to set up and about £850 per month to retain. There is also a minimum 12 month term.
Best practice for keywords on short codes
General rule of thumb: Keep it snappy. Choose a keyword between 3 and 7 characters. The longer the keyword is, the more likely people are to make typos.
Choose an actual word rather than an abbreviation or slang word. If you use anything but a real word, the person’s mobile will attempt to correct it with predictive text.
Avoid using numbers in the keyword. The sender has to switch keyboard, which also makes mistakes more likely. Make the keyword relevant to the campaign. Choose a keyword that matches the context. For example, If your advertising is about a gym membership, choose GYM or FIT.
How much does a keyword cost?
SMS keywords cost £14.00 + VAT a month, with no setup fee. 3-month minimum term (£42 + VAT).
Outbound auto-response texts are charged in line with our standard SMS rates (4.15 pence per automated response). There’s a minimum order of £10 + VAT, which buys you 317 text credits.
Our SMS short codes page goes into a little more detail about how it works, and how to set one up.
How does it differ from a long code?
The catch is short codes aren’t built for natural, back-and-forth conversations. They work best for simple, structured replies. If someone sends a long, free-text message back, you’ll still get it if it’s preceded with the keyword – but it’s not how they’re meant to be used.
Long codes (also known as virtual mobile numbers) are conversational and personal
A long code (also called a Virtual Mobile Number) is like a regular 11-digit phone number, and businesses can purchase these to have their own one. Using one of these means businesses can receive incoming SMS.
Long codes are ideal for customer service chats with back-and-forth problem solving. The key here for any business is to ensure a proper introduction if texting the customer first.
It may also be useful as a call to action for appointment changes, including rescheduling or clarifying details.
And finally, order queries, where customers can ask the notorious ‘where’s my delivery?’ question without feeling like they’re texting a robot.
The trade-off is that long codes send and receive messages aren’t as memorable if you’re advertising the number publicly.
How much does a long code (or Virtual Reply Number) cost?
Reply Numbers cost £13.50 + VAT a month, with no setup fee, minimum term or contract. Incoming texts are not charged. Outbound texts are charged in line with our standard SMS rates.
Users are charged one text at their normal rate to send messages to your dedicated reply number (this is included in their free monthly SMS bundle, if they have one.)
Which should you choose for replies?
It comes down to how you expect customers to respond:
Quick, simple responses at scale? Go for a short code.
Open-ended, personal conversations? Go for a long code.
Some businesses use both:
A short code for marketing campaigns where replies are structured (e.g. ‘Text WIN’).
A long code for back-up, as some people are wary of non-premium shortcodes charging the customer, depending on what their contract says.
The long and the short of it is..
We support both options, so you can pick the one that fits or run them side-by-side.
If you’re inviting customers to reply, think about the type of conversation you want. Short codes are perfect for quick-fire, high-volume interactions. Long codes make it feel like a genuine chat.