That constraint is not a weakness. It is what makes a well-written SMS so effective. The trick is to respect the format rather than fight it.
Start by knowing which job the message is doing
Most business SMS falls into one of three jobs, and each is written differently.
Alerts and reminders
A reminder or confirmation — an appointment, a booking, a due date. The recipient mostly needs the facts, clearly stated, with anything they need to act on made obvious.
Hi Sam, Acme Corp here. Reminder: your appointment with Dr Lee is tomorrow (Tue 12 May) at 2:30pm. Reply C to confirm or call 02 1234 5678 to change.
Marketing
A promotion or offer. It needs to earn attention quickly, be genuinely relevant, and make the next step easy — without over-promising or shouting.
Sam, Acme Corp here. Your favourite winter range is back in stock. 20% off until Sunday: example.com/winter. Reply STOP to opt out.
Business-essential
A message tied to an account or transaction — a statement is ready, a payment is due, a survey follows a service. These are often the most valued messages, because they are useful rather than promotional.
Hi Sam, Acme Corp here. Your April statement is ready to view: example.com/acct. Any questions, just reply to this message.
Six habits of a message that gets acted on
- Lead with who it is from. In a personal inbox, an unfamiliar message is ignored or reported. Make your identity clear immediately.
- Say one thing. A single, clear purpose beats three competing ones. If you have two messages, send two — or reconsider whether SMS is the right channel for the detail.
- Make the next step obvious. One clear action: confirm, tap the link, reply, call. Not several.
- Keep it short and specific. Names, dates and amounts do more work than adjectives. Short is not only cheaper to send, it is more likely to be read.
- Personalise where it genuinely helps. A first name or a relevant detail lifts response; a merge field that misfires does the opposite, so check your data.
- Do not bombard. Frequency is the fastest way to get blocked or reported. Relevance and restraint keep a list responsive.
If you want a reply, set the message up to receive one
This is the part most often overlooked. Whether a recipient can reply at all depends on where your message is sent from.
A branded (alphanumeric) sender — your business name at the top of the message — cannot receive replies. It is one-way. If your message says “reply YES to confirm” but is sent from a branded name, the reply has nowhere to go.
If you want a response, send from a reply-capable number instead. Replies can then be routed back to you, commonly forwarded to email, so you see and can act on them. If you must use a branded sender, give recipients a different way to respond: a link, or a phone number written in the message.
Decide this before you write, not after. “What should the recipient do, and how will their response reach us?” shapes both the wording and the setup.
A quick check before you send
- Is it obvious who the message is from?
- Is there one clear purpose and one clear action?
- Is the whole thing short, specific and free of filler?
- If it asks for a reply, can it actually receive one?
- Does any personalisation hold up against real data?
- Is there a compliant opt-out where the message is promotional?