What is Letter Opener?

letter_opener is a gem that allows you to preview sent emails in the browser instead of sending them to an inbox. It's useful for testing email functionality locally during development without actually sending the emails.

Why Use Letter Opener?

• Convenient for Development: View emails in the browser without filling up your inbox.
• Quick Email Testing: Ideal for testing and verifying email content, formatting, and links without sending real emails.
• Integration with Rails: Easily integrates with Rails' built-in ActionMailer for local testing.

Installation & Setup

• The letter_opener gem is already included in your Gemfile under the :development group:

  group :development do
    gem 'letter_opener', '~> 1.10'
  end
  

• Run bundle install to ensure the gem is installed.

• Configure letter_opener in config/environments/development.rb:

  Rails.application.configure do
    # Use letter_opener to view emails in the browser
    config.action_mailer.delivery_method = :letter_opener
  end
  

  This configuration tells Rails to use the letter_opener gem for email delivery in the development environment.

How Letter Opener Works

• When an email is sent using Rails' ActionMailer, it will automatically open in your default browser.
• You can check the email content (e.g., subject, body, links) in the browser without sending it to an actual inbox.

How to Test Email Sending

Trigger an Email:

• Trigger any email action in the app (e.g., password reset or sign-up emails).
• For example, when you click "Forgot your password?" on the login page, Devise will send a password reset email.

Check the Email:

• After triggering the email action, it will open in your browser for you to review.

Troubleshooting Common Issues

• Email Not Showing in Browser:
  • Ensure that letter_opener is set as the delivery_method in config/environments/development.rb.
  • Double-check that the email action was triggered correctly.
• Email Not Updating in Browser:
  • Refresh your browser or clear the cache if the email doesn’t appear to update after new changes.