> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.pinnacle.sh/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.pinnacle.sh/_mcp/server.

# Sending SMS Messages

> Sending your first SMS with Pinnacle's Ruby SDK

```ruby
require "dotenv/load"
require "rcs"

# Load environment variables
API_KEY = ENV["PINNACLE_API_KEY"]
SENDER_NUMBER = ENV["SENDER_NUMBER"]

# Initialize the Pinnacle client
client = Pinnacle::Client.new(api_key: API_KEY)

# Send an SMS message
client.messages.sms.send_(
  from: SENDER_NUMBER,
  text: "Hello, world!",
  to: "+14154746461" # Recipient's phone number
)

puts "✅ Message sent!"
```

## Prerequisites

Before proceeding, ensure you have obtained a phone number and API key as described in the [prerequisites](/quickstart/sms).

## Installation

Create a `Gemfile` in your project root:

```ruby
source "https://rubygems.org"
gem "dotenv"
gem "rcs", "2.0.15"
```

Install the dependencies:

```bash
bundle install
```

> **Info**
>
> This guide uses version `rcs 2.0.15`. Requires Ruby version >=
> 3.3.0

## Configuration

Create an `.env` file in your project root and add your Pinnacle API key:

```
PINNACLE_API_KEY="your_api_key" # pnclk_
SENDER_NUMBER="your_phone_number" # +12345678910
```

## Sending Your First SMS

Create a new Ruby file (e.g., `send_sms.rb`) and add the following code to the right.

Run the script:

```bash
ruby send_sms.rb
```

If successful, the recipient will receive your SMS message!