SMS length is measured in message segments, not just words. Encoding and special characters can change how much text fits, and a personalized or translated version may be longer than the draft. Review the actual message the customer will receive. The goal is a clear, complete instruction at a sensible cost, rather than the shortest possible text.
Keep the essential information
Identify the store, explain the relevant update, and provide one next action. Remove greetings and repeated adjectives before cutting offer conditions or required opt-out information. The customer should know why the message matters without opening the link just to identify the sender.
Draft in Sendvio and inspect the message length and estimated segment usage for the actual content. Do not assume a single universal character allowance applies to every language or character set. A symbol or non-Latin character can change the encoding behavior.
Understand why one character can change the count
A common GSM-7 SMS allowance is 160 characters for a single segment and 153 per segment when a longer message is joined. Unicode messages commonly allow 70 code units in one segment and 67 per joined segment. Some characters consume more than one unit, and route-specific exceptions exist, so the final counter matters more than a simple visible-letter count.
An emoji, a character outside the supported GSM-7 set, or certain punctuation can change the encoding of the whole message. That means a draft that looks almost identical can require a different number of segments. The lesson is to inspect the final rendered text, not to strip meaningful accents or damage a language merely to make the message appear shorter.
Include the real sender identification, generated link, personalization, and required exit information in the check. A placeholder link or short example name can underestimate the actual message. Review each language version separately because the final encoding and length can differ substantially.
Test the longest realistic version
Personalized names, product labels, and generated links can make the final message longer than the example in the editor. Preview a long value and a missing value, then check that the resulting text remains understandable.
For a restock message, “The medium linen cover is back” communicates more than “Exciting news just for you.” Keep the destination relevant to that specific update. Avoid vague shortened-link language that leaves the customer unsure what they are opening.
Edit the low-value words first
Consider an original draft: “We are very excited to let you know that the medium linen cover you asked about is finally back in stock today.” The useful news is simply that the requested cover is available. A clearer starting point is “The medium linen cover you requested is back.” Then add the store identity, relevant link, and applicable opt-out information.
Do not remove a condition that changes the customer's decision just because it costs space. If an offer applies only to selected items or ends at a specific time, keep the essential meaning and put the full details at a clear destination. A shorter misleading message is not an improvement over a slightly longer accurate one.
Avoid replacing every word with abbreviations. The customer should not need to decode the message, and unfamiliar shorthand can become especially confusing in translations. Read the draft aloud before approving it.
Compare clarity and cost together
Compare the final alternatives by both clarity and cost. If a second segment explains an essential condition, it may be justified. If it merely repeats excitement or a greeting, remove it. When the subject needs a longer explanation, let email or the destination page carry that detail and give SMS one clear job.
Send a test to a real device and inspect the reading experience. Check the final sender identification, link, personalization, and opt-out information together. An editor estimate is useful, but the customer will read that complete version.
After sending, review actual segment usage and current charges alongside customer response and commercial results. Record which edit made the message clearer or changed its cost. Keep that lesson for the next campaign rather than treating a shorter character count as the only sign of improvement.