> ## Documentation Index
> Fetch the complete documentation index at: https://plivo.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Reply to Incoming SMS

> Receive and send automated replies to incoming SMS text messages

## Overview

This guide shows how to receive SMS text messages on a Plivo phone number — something you might want to do to acknowledge a request from a customer, handle opt-ins and opt-outs, or implement an autoresponder application.

You can reply to SMS messages either by using our PHLO visual workflow builder or our APIs. Follow the instructions in one of the tabs below.

<Tabs>
  <Tab title="Using API">
    Here’s how to use Plivo APIs to reply to incoming SMS text messages.

    <h2 id="api-prerequisites">Prerequisites</h2>

    To get started, you need a Plivo account —  [sign up](https://cx.plivo.com/signup) with your work email address if you don’t have one already. To receive incoming messages, you must have a Plivo phone number that supports SMS; you can rent numbers from the [Numbers](https://cx.plivo.com/phone-numbers) page of the Plivo console or by using the [Numbers API](/docs/numbers/). If this is your first time using Plivo APIs, follow our instructions to set up a Go development environment and a web server and safely expose that server to the internet.

    <h2 id="api-create-a-go-server-to-reply-to-messages">Create a Go server to reply to messages</h2>

    Create a file called `reply_sms.go` and paste into it this code.

    ```go theme={null}
    package main

    import (
    	"net/http"
    	"plivo-go/xml"
    )

    func handler(w http.ResponseWriter, r *http.Request) {
    	fromnumber := r.FormValue("From")
    	tonumber := r.FormValue("To")
    	text := r.FormValue("Text")
    	print("Message Received - ", fromnumber, " ", tonumber, " ", text)

    	response := xml.ResponseElement{
    		Contents: []interface{}{
    			new(xml.MessageElement).
    				SetDst(tonumber).
    				SetSrc(fromnumber).
    				SetContents("Thank you, we received your request"),
    		},
    	}
    	w.Write([]byte(response.String()))
    }

    func main() {
    	http.HandleFunc("/replysms/", handler)
    	http.ListenAndServe(":8080", nil)
    }
    ```

    Expose your local server to the internet.

    <h2 id="api-create-a-plivo-application-to-reply-to-messages">Create a Plivo application to reply to messages</h2>

    Associate the Go server you created with Plivo by creating a Plivo application. Visiting Messaging > [Applications](https://cx.plivo.com/xml-applications) and click **Add New Application**. You can also use Plivo's [Application API](/docs/account/api/application/#create-an-application).

    Give your application a name — we called ours `Reply Incoming SMS`. Enter the server URL you want to use (for example `http://<yourdomain>.com/replysms/`) in the `Message URL` field and set the method to `POST`. Click **Create Application** to save your application.

    <Frame>
      <img src="https://mintcdn.com/plivo/2OFvQXVNT3srKLUy/images/create_reply_sms.png?fit=max&auto=format&n=2OFvQXVNT3srKLUy&q=85&s=0371a975aa748267124e9ea9debc7a0f" alt="Create Application" width="1440" height="822" data-path="images/create_reply_sms.png" />
    </Frame>

    <h2 id="api-assign-a-plivo-number-to-your-application">Assign a Plivo number to your application</h2>

    Navigate to the [Numbers](https://cx.plivo.com/phone-numbers) page and select the phone number you want to use for this application.

    From the Application Type drop-down, select `XML Application`.

    From the Plivo Application drop-down, select `Reply Incoming SMS` (the name we gave the application).

    Click **Update Number** to save.

    <Frame>
      <img src="https://mintcdn.com/plivo/NFI9_HRHTMInDf93/images/assign_reply_incoming_sms.png?fit=max&auto=format&n=NFI9_HRHTMInDf93&q=85&s=7f440f6a930c41f1f3393744857b50c3" alt="Assign Phone Number to Reply SMS App" width="1440" height="821" data-path="images/assign_reply_incoming_sms.png" />
    </Frame>

    <h2 id="api-test">Test</h2>

    Send a text message to the Plivo number you specified using any phone. You should receive a reply.
  </Tab>
</Tabs>