> ## Documentation Index
> Fetch the complete documentation index at: https://resend.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Send emails with Ruby
> Learn how to send your first email using the Resend Ruby SDK.
## Prerequisites
Before you start, you'll need:
* A Resend [API key](/create-an-api-key)
* A [verified domain](/add-a-domain)
## 1. Install
Get the Resend Ruby SDK.
```bash RubyGems theme={"theme":{"light":"github-light","dark":"vesper"}}
gem install resend
```
```bash Gemfile theme={"theme":{"light":"github-light","dark":"vesper"}}
gem 'resend'
```
## 2. Send email using HTML
The easiest way to send an email is by using the `html` parameter.
```rb index.rb theme={"theme":{"light":"github-light","dark":"vesper"}}
require "resend"
Resend.api_key = "re_xxxxxxxxx"
params = {
"from": "Acme ",
"to": ["delivered@resend.dev"],
"subject": "hello world",
"html": "it works!"
}
sent = Resend::Emails.send(params)
puts sent
```
## 3. Try it yourself
Basic email sending
Send emails with file attachments
Send emails using Resend hosted templates
Schedule emails for future delivery
Manage contacts and audiences
Create and manage sending domains
Receive and process inbound emails
Double opt-in subscription flow
Full Sinatra web application
Full Rails web application