What is SMS Deliverability and How To Improve It

SMS deliverability

SMS deliverability is the silent killer of mobile marketers today. 

Businesses pay for every text message they attempt to send, not every text that’s received. Carriers can block messages from your campaign for a number of reasons and leaves your company with money on the table. 

If you depend on SMS as a communication channel, knowing that your messages reach subscribers is essential for getting a good return on your investment. 

Don’t leave your marketing campaigns hanging. Master SMS deliverability with these tips. 

What does SMS deliverability mean? 

SMS deliverability is the process responsible for placing a text message into your subscriber’s inbox. It’s expressed as a percentage of all the SMS messages you send. High deliverability rates mean that your messages are successfully reaching their destination. 

Wireless carriers monitor SMS sent over their networks to prevent spam. When they consider an outgoing SMS message spam, they will block it from reaching the recipient’s phone. 

Why do SMS messages fail to deliver? 

There are a few reasons SMS or MMS messages may fail:

1. Spam filters

When you send an SMS campaign, your messages pass through carrier filters, which weed out spam. Spam messages can be texts sent:

  • From alphanumeric or identical sender IDs
  • With similar copy to large groups
  • Without any opt-out instruction 

To avoid SMS spam filters, make sure to personalize text messages and send broadcasts over some time.  

2. Recipient issues or invalid phone numbers 

Phone issues are the most common reason for SMS delivery failures. A subscriber’s mobile phone could be disconnected or turned off, roaming, or be a landline number that can’t receive texts.

3. Gray routes

A gray route is a way to send messages outside of authorized networks, so you avoid paying network operators for delivering the message. Unfortunately, some SMS providers send messages through gray routes. If a carrier spam filter catches any message on a gray route, they won’t deliver it.

That’s why it’s important to find an SMS provider, like ManyChat, that uses an SMS API that goes through compliant to maximize delivery. 

More often than not, SMS deliverability issues are because of incorrect phone numbers. If a subscriber changes their number or gives you the wrong one, your message won’t reach their phone. And you’ll still have to pay for the message. 

How to improve SMS and MMS message deliverability

1. Clean your contact list

Go through your SMS subscriber list and remove incorrect phones and unengaged contacts regularly. You want to ensure your text messages are sent to an interested audience. This will boost your SMS metrics and improve your sender reputation. 

2. Set up double opt-in to your subscriber list 

Send new SMS subscribers a confirmation message after opt-in. It’s required by law and can help set expectations for contacts, plus, it establishes your identity. Unfamiliar phone numbers increase the likelihood of being blocked or reported as spam. 

In the example below, Fletcher Goods, an outdoor eCommerce store, sends the standard confirmation message as a double opt-in. After the subscriber confirms their subscription, Fletcher Goods follows up with a warm welcome from a Customer Success representative. 

SMS Deliverability example

Double opt-in keeps you compliant and ensures a new subscribers number is active and that they’ll likely engage with your texts, which can increase your SMS delivery rate.   

3. Don’t send spam messages

For each message you send, include opt-out instructions, concise language, and proper capitalization and punctuation to avoid spam filters. Also, try to include your name in messages and explain why a receiver is getting your texts. 

Here’s an SMS example of how not to text subscribers if you want to send a promotion:

example of bad SMS message

Here’s a good example of a personalized message that will likely get delivered:

Example of good SMS message

4. Don’t send bulk SMS too fast

Many people begin their SMS marketing efforts with a broadcast to their entire list. When high volume SMS messages are sent from a number, carriers can flag the broadcast and block your messages.

A common myth is that SMS is for mass texting like this, but it’s rarely as effective as you may think. If you want to send bulk SMS, make sure to time your messages throughout the day to improve deliverability. 

5. Avoid sending links from domains you don’t control

One thing carriers look for when deciding to deliver your SMS is the link domain name. If it’s mysterious or public, they can block the message and your contact will never see it. 

Bit.ly and similar link shortener services can trigger this red flag by carriers. The worse part? If flagged domains like bit.ly are in a timeout state, and you send a message with a bit.ly link, the carrier may keep your money, but never send the message to your recipient.  

If you want to send links, try to use your domain for shortening links to build a reputation with carriers and improve deliverability. 

6. Two-way text with your customers

A two-way SMS Live Chat with customers is a smart way to improve SMS deliverability and increase sales. When carriers see recipients in an active conversation with your business, it shows your credibility and can improve the chances of getting your messages through in future campaigns. 

How to measure SMS deliverability

There is no exact timeframe to measure SMS deliverability. You can record delivery rates daily, monthly, or quarterly.

The deliverability rate equation is:


If you’re using an SMS provider like ManyChat, you can find your SMS delivery rate listed in your SMS message block in Flow Builder.

Note that message delivery isn’t how many messages are sent. It only measures how many messages were delivered versus the number intended in a specific time frame. 

SMS Deliverability FAQ

Are text messages guaranteed to be delivered?

No, text messages are not guaranteed to be delivered. Many factors — such as SMS API, incorrect numbers, and spam filters — that influence whether your SMS message gets delivered promptly. 

How reliable is SMS?

SMS is one of the most reliable forms of communication with a high delivery rate. Research suggests that 90% of text messages are opened within three minutes of receiving it. 

How do wireless carriers filter messages?

Wireless carriers place a cumulative score on messages based on:

  • How many texts come from a phone number during a given period.
  • How many similar messages have traversed the carrier’s network.
  • If the content in your message is a high match for spam.

Getting the most from your SMS messaging

Now that you have a good understanding of how to optimize SMS communication,  it’s time to start messaging with your subscribers. With these tips in hand, you’ll get higher SMS delivery rates and show better ROI for text messaging strategy. 

Disclaimer: This information is provided for educational purposes only and should not be relied upon as legal advice. Please always consult your own attorney before engaging in text marketing.

Want to get better ROI from your SMS marketing efforts? Get ManyChat today. It’s free to get started.

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