SureSMS guide
Text Messages End Up in the Spam Folder: Causes and Solutions
Some companies find that text messages are sent and delivered correctly but are still not seen by the recipient because the phone filters them as spam or messages from an unknown sender. Here are the typical causes—and the best ways to reduce the risk.
Main points
- An SMS may be considered technically delivered even if the recipient does not see it in their regular inbox.
- Spam filters on your phone can respond to the sender, content, links, a large number of similar messages, and user behavior.
- The risk can often be reduced by using a known sender, more personalized messages, fewer links, and smarter sending patterns.
There is a difference between whether a text message has been delivered and whether it has been read. In many SMS systems, a message may appear as sent or delivered, even though the recipient’s phone subsequently moves it out of the main inbox. To the recipient, it seems as if the message never arrived.
This is particularly evident in bulk messages, campaigns, and messages from senders that the phone does not recognize. However, it can also affect entirely legitimate operational communications, such as reminders to employees, service messages, or practical messages sent to many recipients at the same time.
Why do text messages end up in spam?
Spam filtering typically takes place on the recipient’s phone or in the messaging app. This means that there is rarely a single technical setting in the SMS platform that can completely eliminate the problem. The filters evaluate a combination of signals.
- The sender is unknown: If the message comes from a sender name or number that the recipient has not saved, the risk may be higher.
- Many similar messages are sent in a short period of time: Identical text sent to many recipients may appear to be an automated mass mailing.
- Recipients have marked messages as spam: If several users have previously marked the same sender as spam, this may affect future messages.
- The message contains links: Links, short links, and very generic landing pages can increase the risk of being filtered.
- The text is very short or generic: Messages without context are more likely to be mistaken for spam than messages with clear relevance.
When a message ends up in the spam folder, it doesn't necessarily mean that the text message failed for technical reasons. It may have been delivered to the phone but hidden or sorted differently by the phone's messaging app.
Android and Spam Filtering
On Android, messaging apps like Google Messages can use spam filters that evaluate the sender, the content, and past user behavior. This can particularly affect messages from senders the recipient doesn't know, or messages that look like mass mailings.
If the recipient finds the message in the spam folder, they should mark it as “Not spam.” This can help the phone recognize that the sender is legitimate.
iPhone and Unknown Senders
On the iPhone, users can choose to filter messages from unknown senders. This is typically less intrusive than traditional spam blocking, but the result can be the same: the message isn't where the recipient usually looks.
For businesses, this means that a recognizable sender and clear context are becoming increasingly important. The easier it is for the recipient to recognize the sender and the purpose of the message, the better.
How to Reduce the Risk
There is no guarantee against filtering, but there are several practical measures that can usually reduce the risk significantly.
1. Use a phone number when it makes sense
Alphanumeric senders, such as company names, are easy to recognize, but they cannot be saved or replied to in the same way as a phone number. For some types of communication, it may therefore be advantageous to send a message from a phone number.
If recipients save the number in their contacts, the risk of the message being perceived as coming from an unknown sender is reduced. This is particularly relevant for recurring operational messages, on-call notifications, internal reminders, or two-way text messages.
With two-way SMS, the company can send messages from a specific number and receive replies directly within the platform. This makes the sender more identifiable and can also improve the workflow if recipients need to reply.
2. Ask the recipients to save the sender's information
If the messages are sent from a phone number, the number should be saved as a contact. On Android, in some cases, the recipient can also save an alphanumeric sender as a contact directly from the message. This can help the phone recognize the sender in the future.
3. Make the messages more personalized
A message that begins with the recipient's name, department, or relevant context seems less generic than a text that is exactly the same for everyone. For example, it could be:
- “Hi Mette, remember to log your hours by Friday at 12 p.m. at the latest.”
- “Hi, warehouse team, there’s been a change in tomorrow’s meeting time.”
- “Hi Peter, your appointment with us is tomorrow at 9:30 a.m.”
Personalization helps both the recipient and the filters. The message becomes more relevant, and it looks less like an anonymous mass mailing.
4. Avoid unnecessary links
Links are one of the factors most likely to increase the risk. If the message can be understood without a link, that’s often better. If a link is necessary, it should be a recognizable, branded domain rather than a generic short link.
5. Don't send everything all at once
If 100, 500, or 5,000 nearly identical messages are sent in a very short period of time from the same sender, it may appear to be automated spam traffic. For non-urgent messages, it may be beneficial to spread out the sending over a few minutes.
For example, it rarely matters if an internal reminder is sent 5–10 minutes later instead of in a few seconds. This can result in a more natural sending pattern.
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- Is the sender recognizable to the recipient?
- Can the sender's number be saved as a contact?
- Is the message personalized enough, or is it exactly the same for everyone?
- Does the message contain any links that aren't necessary?
- Does the link use a recognizable domain?
- Can the broadcast be spread out over a few minutes?
- Do recipients know that they shouldn't mark legitimate messages as spam?
- Is there an alternative channel if the message is critical?
Conclusion
Text messaging remains a powerful channel for important communication, but spam and sender filters on phones mean that companies need to give more thought to the sender, content, and sending patterns than they did in the past.
The best solution is rarely a single change. It’s a combination of a recognized sender, clear text, fewer links, more personalization, possibly two-way SMS, and a plan for what the recipient should do if a message ends up in the spam folder.