When deciding text messaging strategy, businesses must clearly understand their needs, consider their partners' SMS distribution capabilities, and remember that strict legal restrictions apply to messaging in many countries.

Businesses must also rely on the existing best practices of contacting customers developed by market players and state authorities.

This article aims to raise business awareness of some important factors in messaging communications.

Aircall SMS functionality

Aircall clients can engage with their customers via a two-way SMS messaging channel, known as a ‘Conversational SMS’ feature.

Our product does not support automated or one-way SMS messaging that some businesses may wish to utilize in their marketing campaigns. If you need this functionality, please feel free to review our supported Third-Party SMS solutions.

Anticipating your messaging requirements

Define your messaging needs

Before using a communication channel like text messaging for business purposes, it is important to choose a service provider adapted to your usage type.

Some helpful elements when deciding on a particular solution are provided below. Please communicate your answers to your Aircall Account Manager to see how Aircall can provide the best solution to answer your messaging needs.

Messaging need

  • Separate messaging channel, whereby dedicated number(s) will be used for messaging

  • Complementary messaging channel, whereby number(s) may be used for both voice and messaging

Use case

  • Internal communications

  • External communications (e.g marketing, sales, or customer support)

SMS Outbound volume per month

Volume in a range

  • Up to 500 messages

  • Between 501 and 1,000

  • Between 1,001 and 5,000

  • Between 5,001 and 10,000

  • 10,001 or more

Inbound volume per month

Volume in a range

  • Balanced: equal or within 10% to the outbound volume

  • Unbalanced: half the outbound volume

  • Limited inbound volume compared to outbound

Number of users

Number of users

  1. Per Phone Number

  2. Requiring access to Message enabled numbers

Local requirements and industry practices

We recommend seeking legal advice from a local qualified adviser to make sure your messaging communications are in compliance with all applicable laws, regulations, and industry practices. The requirements applicable to messaging communications may vary by country.

For instance, there is a requirement to register phone numbers used for messaging campaigns in the United States (more information can be found here) and a requirement for the verification of toll-free numbers for using SMS services in Canada and the United States (more information here).

Prohibited content and use cases

Aircall and its suppliers prohibit sending any content that is illegal, harmful, unwanted, inappropriate, objectionable, confirmed to be criminal misinformation content, or otherwise poses a threat to the public, even if it is permissible by law.

Prohibited content includes but is not limited to:

  • Hate speech, harassment, incitement to terrorism, exploitative, and abusive content;

  • Phishing and fraudulent messages;

  • Malicious content, such as malware or viruses;

  • Any content that is designed to intentionally evade carrier filtering (such as spreading similar messages across different numbers - also known as “snowshoeing”); and

  • Deceptive marketing, pyramid or multi-level marketing, high risk financial services or activities, gambling, “get rich” schemes.

Messaging best practices


Commercial messages can only be sent to recipients if they have given their consent to receiving such communications.

Implementation of opt-in depends on the type of communication:

  • Conversational messaging communications: consent is implied when a back-and-forth conversation takes place for a specific topic or purpose. Especially if a consumer is the one initiating the discussion. No need for explicit consent.

  • Informational messaging communications: consent is given when a recipient has given you its contact details to receive information (e.g. via a website, etc.)

  • Promotional messaging communications: consent must be given in writing (filling out a form for instance) for sales/marketing messages, especially those with calls to action.

Consent is contextual and does not allow you to send messages other than what the recipient has agreed to receive.

For promotional purposes, it is strongly advised to set the proper expectation with the customer on how many messages they can expect to receive, especially if you intend to send more than five (5) text messages per month.


Opt-out is a process where customers can request the sending of promotional materials and messages to their number be stopped. The practice differs around the world and in some countries the opt-out function is a mandatory part of messaging by law. It usually comes at the end of a message as instructions on how to opt-out, such as “Send STOP to opt out,” or by providing an email or web address so that customers can opt-out by entering their number.

If a customer replies with an opt-out keyword, such as ‘STOP’, no further communications should be sent to them.

Opt-out command is enabled by default on most of our SMS-enabled numbers. Please ask your Aircall Account Manager to confirm this for you.

In the United States, when receiving an opt-out keyword such as STOP, UNSUBSCRIBE or CANCEL, the number is automatically blocked from further text communications from the number used for sending the text.

In such a case, the recipient will automatically receive the response ‘You have successfully been unsubscribed. You will not receive any more messages from this number. Reply START to resubscribe.’ The blocklist does not work at a company level. If you send text messages from multiple numbers to the same recipients, you should manually ensure recipients’ numbers are blocked on all numbers, or work with Aircall’s specialized partners to do so.

Sender Identification

A business sending a message must provide its identification information in it. Depending on the country, senders may have an obligation to provide such information either at the beginning of communications (i.e. in the first message) or in each message.

Message length and URLs

From a practical standpoint, to avoid the delivery of messages being blocked by carriers’ anti-spam filters, you may consider not using:

  • messages of more than 250 characters;

  • URL shorteners like tinyurl and bitly, as they are associated with fraudulent communications;

  • different domains or subdomains for each message (the practice is known as ‘URL Cycling’); and

  • URL addresses redirecting to other URL addresses resulting in the recipient not knowing which website they will eventually be taken to.

SMS Traffic whitelisting

In some countries, national regulation or industry practices may restrict sending commercial messages outside business hours.

Additionally, for the United States you are also encouraged to refrain from sending messages to non-SMS enabled numbers. As these messages cannot be delivered to the recipient, downstream operators will experience a high rate of delivery errors and may be forced to block further communication from a number with a high delivery error rate. To mitigate this risk, you can exclude non-SMS enabled numbers from the message distribution list. Consider using a look-up service to check numbers, such as https://numverify.com/.

Cross-check numbers against Do-Not-Contact-Registries

In many countries, end-users can opt out of receiving commercial messages by signing up to Do-Not-Contact or Do-Not-Disturb-Registries. Before sending messages, you should cross-check if the phone numbers to which you wish to place text messages are in the registers.

The information contained in this Article is provided for informational purposes only and should not be construed as legal advice. It may not reflect current legal developments or address your situation. You should not act or refrain from acting on the basis of any content included in this article without seeking legal or other professional advice. Aircall disclaims all liability for actions you take or fail to take based on any content on this website.

Still in need of assistance? Please feel free to reach out to the Support Team and we will be happy to assist!

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