Mandrill

Mandrill (now owned by Intuit Mailchimp) is an email transactional service.

We're mostly interested in Mandrill's inbound email processing feature.

Things we're going to do:

1. Create an account at mailchimp.com and set up their transactional email demo
2. Think of a subdomain for use with RBE. eg. reply.example.com
3. Add Mandrill's MX records to this subdomain
4. In Mandrill, register the subdomain and add a route
5. (Optional) Increase security by adding a few defines to your wp-config.php file
6. Install RBE and add the subdomain to RBE's settings page

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Installation instructions:

1) Create an account at mailchimp.com and set up their transactional email demo

Create a free account at Mailchimp.com at https://mailchimp.com/signup/?plan=free_monthly_plan_v0&locale=en.

Once you've created the account, login to their admin dashboard and follow these steps to set up their Transactional Email Demo:
https://mailchimp.com/help/transactional-email-demo/#Try_the_Mailchimp_Transactional_demo

A big caveat with their Transactional Email Demo is you can only receive 100 inbound emails a day. What this means is if you anticipate your users replying by email (or posting forum topics by email) more than 100 times a day, you will have to upgrade your account to Mailchimp's Standard tier, which is $20/month.

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2) Think of a subdomain for use with RBE

Once you have set up Transactional Email, you'll need to think of a subdomain to use exclusively with RBE.

Let's say example.com is your WordPress site, you'll want to create a dedicated subdomain used only by Mandrill. eg. reply.example.com. Change reply to whatever suits your fancy. This will be used in emails for the Reply-To email header - XXX@reply.example.com - so choose carefully.

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3) Add Mandrill's MX records for your new subdomain

With your new, chosen subdomain, go to this page:
https://mandrillapp.com/inbound

This will ask you to login at Mailchimp.

Next, follow these instructions:
https://mailchimp.com/developer/transactional/guides/set-up-inbound-email-processing/#add-your-inbound-domain

Basically, you will click on the View Setup Instructions button and you should see something like this:

Copy the MX records as shown when you clicked on the View Setup Instructions button and configure your subdomain to use these records in your domain registrar's dashboard.

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4) In Mandrill, register the subdomain and add a route

In Mandrill, go back to this page:
https://mandrillapp.com/inbound

At the top of the page, there should be a form to add domains. Enter in the subdomain you have set up (eg. reply.example.com) and click on the Add button.

This should add the domain to the rest of the domain list. Now, click on the domain that was just added to the list (eg. reply.example.com).

This should open up a new page with a Add New Route button. Click on that button and enter the following:

• For When the receiving email address matches:, enter *
• For Post to URL, enter the URL to your WordPress install

Hit Save.

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5) (Optional) Increase security by adding a few defines to your wp-config.php file

When you just created your route, Mandrill automatically created a key for this inbound email webhook. You can find this webhook here:
https://mandrillapp.com/settings/webhooks/

On this page, find the key for the route you just created and copy it.

Next, in your wp-config.php file (or a similar file where you might have other PHP constants), add the following lines:

// This should be the same URL you used when you registered your route in step 4.
define( 'BP_RBE_MANDRILL_WEBHOOK_URL', 'ENTER YOUR WEBHOOK URL HERE' );

// This should be the key you copied from https://mandrillapp.com/settings/webhooks/
define( 'BP_RBE_MANDRILL_WEBHOOK_KEY', 'PASTE YOUR WEBHOOK KEY HERE' );

This will increase security to ensure that webhook responses were actually sent from Mandrill.

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6) Install and configure RBE on your WordPress site

1. Download the latest master branch of RBE - https://github.com/r-a-y/bp-reply-by-email/archive/master.zip
2. Extract the plugin to /wp-content/plugins/.
3. Login to the WP admin dashboard and activate RBE. Next, navigate to BuddyPress > BP Reply By Email.
4. Do the following:
   • For Mode, select Inbound Email.
   • For Provider, select Mandrill.
   • For Inbound Domain, type in the subdomain you set up in Mandrill. Save the settings.
5. Now test out RBE! At-mention someone on the frontend and try to reply to that person via email. See if a reply is sent back. If you are able to reply to one another, RBE is working!