# Rails Mailers

> Use when sending emails - ActionMailer with async delivery via SolidQueue, templates, previews, and testing

- **Type:** Skill
- **Install:** `agentstack add skill-shoebtamboli-rails-claude-skills-rails-mailers`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [Shoebtamboli](https://agentstack.voostack.com/s/shoebtamboli)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [Shoebtamboli](https://github.com/Shoebtamboli)
- **Source:** https://github.com/Shoebtamboli/rails_claude_skills/tree/main/lib/generators/claude/skills_library/rails-mailers
- **Website:** https://rubygems.org/gems/rails_claude_skills

## Install

```sh
agentstack add skill-shoebtamboli-rails-claude-skills-rails-mailers
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Email with ActionMailer

Send transactional and notification emails using ActionMailer, integrated with SolidQueue for async delivery. Create HTML and text templates, preview emails in development, and test thoroughly.

- Sending transactional emails (password resets, confirmations, receipts)
- Sending notification emails (updates, alerts, digests)
- Delivering emails asynchronously via background jobs
- Creating email templates with HTML and text versions
- Testing email delivery and content

- **Async Delivery** - ActionMailer integrates with SolidQueue for non-blocking email sending
- **Template Support** - ERB templates for HTML and text email versions
- **Preview in Development** - See emails without sending via /rails/mailers
- **Testing Support** - Full test suite for delivery and content
- **Layouts** - Shared layouts for consistent email branding
- **Attachments** - Send files (PDFs, images) with emails

Before completing mailer work:
- ✅ Async delivery used (deliver_later, not deliver_now)
- ✅ Both HTML and text templates provided
- ✅ URL helpers used (not path helpers)
- ✅ Email previews created for development
- ✅ Mailer tests passing (delivery and content)
- ✅ SolidQueue configured for background delivery

- ALWAYS deliver emails asynchronously with deliver_later (NOT deliver_now)
- Provide both HTML and text email templates
- Use *_url helpers (NOT *_path) for links in emails
- Set default 'from' address in ApplicationMailer
- Create email previews for development (/rails/mailers)
- Configure default_url_options for each environment
- Use inline CSS for email styling (email clients strip external styles)
- Test email delivery and content
- Use parameterized mailers (.with()) for cleaner syntax

---

## ActionMailer Setup

Configure ActionMailer for email delivery

**Mailer Class:**

```ruby
# app/mailers/application_mailer.rb
class ApplicationMailer 
Welcome, !
Thanks for signing up. Get started by logging in:

```

**Text Template:**

```erb

Welcome, !

Thanks for signing up. Get started by logging in:

```

**Usage (Async with SolidQueue):**

```ruby
# In controller or service
NotificationMailer.welcome_email(@user).deliver_later
NotificationMailer.password_reset(@user).deliver_later(queue: :mailers)
```

**Why:** ActionMailer integrates seamlessly with SolidQueue for async delivery. Always use deliver_later to avoid blocking requests. Provide both HTML and text versions for compatibility.

Using deliver_now in production (blocks HTTP request)

```ruby
# ❌ WRONG - Blocks HTTP request thread
def create
  @user = User.create!(user_params)
  NotificationMailer.welcome_email(@user).deliver_now  # Blocks!
  redirect_to @user
end
```

```ruby
# ✅ CORRECT - Async delivery via SolidQueue
def create
  @user = User.create!(user_params)
  NotificationMailer.welcome_email(@user).deliver_later  # Non-blocking
  redirect_to @user
end
```

**Why bad:** deliver_now blocks the HTTP request until SMTP completes, creating slow response times and poor user experience. deliver_later uses SolidQueue to send email in background.

Use .with() to pass parameters cleanly to mailers

```ruby
class NotificationMailer 

---

## Email Templates

Shared layouts for consistent email branding

**HTML Layout:**

```erb

  
    
    
      body {
        font-family: Arial, sans-serif;
        max-width: 600px;
        margin: 0 auto;
        color: #333;
      }
      .header {
        background-color: #4F46E5;
        color: white;
        padding: 20px;
        text-align: center;
      }
      .content {
        padding: 20px;
      }
      .button {
        display: inline-block;
        padding: 12px 24px;
        background-color: #4F46E5;
        color: white;
        text-decoration: none;
        border-radius: 4px;
      }
      .footer {
        padding: 20px;
        text-align: center;
        font-size: 12px;
        color: #666;
      }
    
  
  
    
      Your App
    
    
      
    
    
      © 2025 Your Company. All rights reserved.
    
  

```

**Text Layout:**

```erb

================================================================================
YOUR APP
================================================================================

--------------------------------------------------------------------------------
© 2025 Your Company. All rights reserved.
```

**Why:** Consistent branding across all emails. Inline CSS ensures styling works across email clients.

Attach files to emails (PDFs, CSVs, images)

```ruby
class ReportMailer 

```

**Why:** Attach reports, exports, or inline images. Inline attachments can be referenced in email body with image_tag.

Using *_path helpers instead of *_url in emails (broken links)

```ruby
# ❌ WRONG - Relative path doesn't work in emails
def welcome_email(user)
  @user = user
  @login_url = login_path  # => "/login" (relative path)
  mail(to: user.email, subject: "Welcome")
end
```

```ruby
# ✅ CORRECT - Full URL works in emails
def welcome_email(user)
  @user = user
  @login_url = login_url  # => "https://example.com/login" (absolute URL)
  mail(to: user.email, subject: "Welcome")
end

# Required configuration
# config/environments/production.rb
config.action_mailer.default_url_options = { host: "example.com", protocol: "https" }
```

**Why bad:** Emails are viewed outside your application context, so relative paths don't work. Always use *_url helpers to generate absolute URLs.

---

## Email Testing

Preview emails in browser during development without sending

**Configuration:**

```ruby
# Gemfile
group :development do
  gem "letter_opener"
end

# config/environments/development.rb
config.action_mailer.delivery_method = :letter_opener
config.action_mailer.default_url_options = { host: "localhost", port: 3000 }

# config/environments/production.rb
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: "smtp.sendgrid.net",
  port: 587,
  user_name: Rails.application.credentials.dig(:smtp, :username),
  password: Rails.application.credentials.dig(:smtp, :password),
  authentication: :plain,
  enable_starttls_auto: true
}
config.action_mailer.default_url_options = { host: "example.com", protocol: "https" }
```

**Why:** letter_opener opens emails in browser during development - no SMTP setup needed. Test email appearance without actually sending.

Preview all email variations at /rails/mailers

```ruby
# test/mailers/previews/notification_mailer_preview.rb
class NotificationMailerPreview 

Test email delivery and content with ActionMailer::TestCase

```ruby
# test/mailers/notification_mailer_test.rb
class NotificationMailerTest 

---

## Email Configuration

Configure ActionMailer for each environment

**Development:**

```ruby
# config/environments/development.rb
config.action_mailer.delivery_method = :letter_opener
config.action_mailer.perform_deliveries = true
config.action_mailer.raise_delivery_errors = true
config.action_mailer.default_url_options = { host: "localhost", port: 3000 }
```

**Test:**

```ruby
# config/environments/test.rb
config.action_mailer.delivery_method = :test
config.action_mailer.default_url_options = { host: "example.com" }
```

**Production:**

```ruby
# config/environments/production.rb
config.action_mailer.delivery_method = :smtp
config.action_mailer.perform_deliveries = true
config.action_mailer.raise_delivery_errors = false
config.action_mailer.default_url_options = {
  host: ENV["APP_HOST"],
  protocol: "https"
}

config.action_mailer.smtp_settings = {
  address: ENV["SMTP_ADDRESS"],
  port: ENV["SMTP_PORT"],
  user_name: Rails.application.credentials.dig(:smtp, :username),
  password: Rails.application.credentials.dig(:smtp, :password),
  authentication: :plain,
  enable_starttls_auto: true
}
```

**Why:** Different configurations per environment. Development previews in browser, test stores emails in memory, production sends via SMTP.

---

```ruby
# test/mailers/notification_mailer_test.rb
class NotificationMailerTest 

---

- rails-ai:jobs - Background job processing with SolidQueue
- rails-ai:views - Email templates and layouts
- rails-ai:testing - Testing email delivery
- rails-ai:project-setup - Environment-specific email configuration

**Official Documentation:**
- [Rails Guides - Action Mailer Basics](https://guides.rubyonrails.org/action_mailer_basics.html)

**Gems & Libraries:**
- [letter_opener](https://github.com/ryanb/letter_opener) - Preview emails in browser during development

**Tools:**
- [Email on Acid](https://www.emailonacid.com/) - Email testing across clients

**Email Service Providers:**
- [SendGrid Rails Guide](https://docs.sendgrid.com/for-developers/sending-email/rubyonrails)

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [Shoebtamboli](https://github.com/Shoebtamboli)
- **Source:** [Shoebtamboli/rails_claude_skills](https://github.com/Shoebtamboli/rails_claude_skills)
- **License:** MIT
- **Homepage:** https://rubygems.org/gems/rails_claude_skills

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** yes
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-shoebtamboli-rails-claude-skills-rails-mailers
- Seller: https://agentstack.voostack.com/s/shoebtamboli
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.