> For the complete documentation index, see [llms.txt](https://docs.hollatags.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hollatags.com/master.md).

# Introduction

### Overview

HollaTags API enables you to seamlessly integrate SMS, USSD & Voice functionalities into your website or application.

The documentation is broken into two main parts based on connection protocol - [**HTTP**](/sms/send.md) *(POST/GET)* or [**SMPP**](/smpp/smpp-specification.md). Customers are encouraged to use the protocol of their choice. Typically, high volume customers will use [SMPP](/smpp/smpp-specification.md) connection.

If you require any assistance, please email our dev support team at <help@hollatags.com>

### API Endpoint

In order to use HollaTags APIs, you need to first sign up for free at <https://sms.hollatags.com> . The API Endpoint is <https://sms.hollatags.com/api/>

### API Response

All responses for the HTTP API are plain text with a 200 OK status even for errors. Please use the [**API Response** ](/sms/api-response.md)page for the list of all possible responses for success and error.

### SMPP Connection

HollaTags SMPP interface provides support for almost all features of SMPP within the official specification and without proprietary deviation. You can download the full specification here - <http://opensmpp.org/specs/SMPP_v3_4_Issue1_2.pdf>

The following pages provide details on [authentication](/smpp/authentication.md), [configuration](/smpp/connection.md), [supported pdu](/smpp/message-pdu.md) and [sample smpp client configurations](/smpp/client-configuration.md).