> For the complete documentation index, see [llms.txt](https://guides.clickatell.com/sms-channel/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://guides.clickatell.com/sms-channel/1-way-sms-communication.md).

# 1-way SMS communication

**1-way** SMS communication involves **sending** messages only, i.e., customers cannot reply to the messages sent by your business.  

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**Note:** 1-way messaging is not allowed in some countries (e.g., the USA).
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To engage in 1-way SMS communication, you do **not** require a dedicated number. 

When selecting 1-way messaging as part of the [SMS setup wizard](/sms-channel/getting-started/add-new-sms-setups-self-serve.md), you are **not** required to purchase a long number/short code, and a **random number** will be used as the *from* number.

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Learn how to send 1-way messages using [One API](https://docs.clickatell.com/channels/one-api/one-api-reference/#tag/One-API/operation/sendMessageREST).
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