Best practices for sending email to lots of recipients (Rails + SendGrid)

Question

I will be sending bulk emails from a Rails app and plan on using SendGrid. I am assuming that it is best to send a separate email to each recipient (as opposed to using BCC

Answer 1

This is how I've done it in Rails 4

class NewsMailer < ApplicationMailer
  include SendGrid

  sendgrid_category :use_subject_lines

  default from: 'My App! '

  def mass_mailer(news)
    # Pass it in template
    @news = news

    # Custom method to get me an array of emails ['user1@email.com', 'user2@email.com',...] 
    array_of_emails = @news.recipients.pluck(:email) 

    # You can still use
    # headers["X-SMTPAPI"] = { :to => array_of_emails }.to_json
    sendgrid_recipients array_of_emails

    mail to: 'this.will.be.ignored@ignore.me', subject: 'Weekly news'
  end

end