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Ruby library for sending mailmerge messages to a PowerMTA mail server.
Branch: master

Merge pull request #1 from saldan/master

XACK feature and minor fix to README
latest commit a64769fe10
@iwarshak authored
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lib Added support for XACK ON/OFF + class name change
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Rakefile updated description
VERSION Version bump to 0.1.0
powermta.gemspec bump



This is an extension to Ruby's net/smtp library that lets you take advantage of PowerMTA's ( native mailmerge and XACK features.

If you are doing any kind of mass mailing and you want the message to be unique to each user, and not one email with 50000000 people bcc'ed on it, this extension is for you.

I extracted this library from, which literally sends hundreds of thousands of time-sensitive emails a day.

Example usage:

require 'pmta_extension'

users = User.find(:all)

email_text =<<-EOF 
  From: "your friendly social network" <>
  To: [*to]
  Subject: Howdy [firstname]

  Dear [firstname],

  Did you know that you have [friend_count] friends? You must be one popular [gender]!!!

  Your friends at NoseBook

addresses = []
users.each do |user|
  addresses << {:address =>, 
                :variables => {"firstname" => user.firstname, "friend_count" => user.friends.size, "gender" => user.gender == "m" ? 'dude' : 'gal'}}

Net::PowerMTA.start('', 25) do |smtp|
  smtp.disable_xack  # if you want to ignore ACK on RCPT TO and XDFN commands
  smtp.send_merge_message(email_text, '', true, addresses)

That's it. Now instead of having to compose and send User.size custom emails (which can take forever), you can send 1 mailmerge message to the PowerMTA server (the mail server) and have it do all of the merging for you.

Feel free to email me with any questions. Ian Warshak <>

Note on Patches/Pull Requests

  • Fork the project.

  • Make your feature addition or bug fix.

  • Add tests for it. This is important so I don't break it in a future version unintentionally.

  • Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

  • Send me a pull request. Bonus points for topic branches.


Compatible for ruby >= 1.8.7 and <= 2.1.2


Copyright © 2010 Ian Warshak. See LICENSE for details.

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