> For the complete documentation index, see [llms.txt](https://help.clickatell.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.clickatell.com/ussd-user-guide/getting-started/ussd-features.md).

# USSD features

{% hint style="success" %}
USSD allows for messages with a maximum of **182 characters**. However, due to differences in the minimum number of characters accepted by the Mobile Network Operators, we recommend you remain within **160 characters**.
{% endhint %}

Clickatell offers two types of USSD messaging services: 

* **Mobile-initiated interactive messaging** **(or USSD pull):** This enables the customer to dial a number (e.g., \*100#) to initiate a session via their handset. Information could also be displayed as a menu that the customer can respond to and interact with.
* **Network-initiated interactive messaging** **(or USSD push):** This is when the session to the handset is initiated by the application. Similar to mobile-initiated, this information could be a menu that the customer can respond to and interact with.

{% hint style="warning" %}
USSD push is not available in Chat Flow yet.
{% endhint %}

These USSD messaging services are offered for all types of [service codes](/ussd-user-guide/getting-started/service-codes.md).


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