Do Raley Emails Notifications store private data as defined by Atlassian.

No, we do not store user's private data

Where are you hosted?

Our servers are located in New York City, US.

Who has access to Raley?

By default, access to Raley configuration console is only permitted to users who have permissions ADMINISTER or JIRA_ADMIN in your host Jira, i.e. Jira administrators.

However, you can specify additional Jira user groups which are allowed to access Raley Emails Notifications console. To do that, navigate to Settings and provide Jira groups in "User Groups with Access to Raley" combo box.

Note, that Raley Issue panels (instant send notification) is permitted for any authorized user who has access to your Jira ticket.

Are Raley notifications replacing standard Jira/JSM notifications?

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Emails can be sent from the following IP's:
104.236.5.8845.55.225.41

45.55.218.70

161.35.132.150

138.197.14.52

64.225.21.7

What do I need to get started with Raley Notifications?

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Yes, please have a look here: Predefined Customer Email Notification templates. Also, you're most welcome to use our Template Wizard

We have another add-on that has to do something before Raley should handle the Jira event. Can you delay your processing?

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#foreach ($issue in $issues)
 Project: $issue.fields.project.name Issue type: $issue.fields.issuetype.name
 Date and time of creation: $jirassimo.formatDate($issue.fields.created, "dd MMM yy hh:mm")
 Reporter: $issue.fields.reporter.name
#end

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To format a numeric JIRA field use $jirassimo.formatNumber(numberField, outputFormat) function. An example of usage:
$jirassimo.formatNumber($issue.customfield_12345, "#")
Assuming that customfield_12345 contains a value 10.45 the result will be 10. We use Java DecimalFormat to format the values. 

How to use Settings?
Settings is essentially a map of key=value pairs stored with Raley. At runtime you can get a value referenced by key using the following expression:
$jirassimo.settingValue($issue.fields.customfield_10000)
This will return a setting's value that corresponds to key stored in $issue.fields.customfield_10000Check out this article.

Sending to different Slack channels depending on user's email
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This is another name for scheduled messaging. The whole idea here is that Raley will not react on specific events in your host JIRAJira, but rather poll it at specific times and send messages about issues that are relevant to JQL.
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Insufficient privileges in JIRA Jira - for instance, retrieval of related users or projects. 
Errors during template evaluation. Some fields might be missing or in wrong format
Bad credentials for Email or Slack. 
IO related problems
These errors would be normally reported to user on the list of Raley notifications just below the names of respective messengers. When you fix it, assuming that the fix was correct, the error message will disappear next time the current messenger is successfully run.
Also, you can check Send Audit tab and look for the notifications that have Status = Error.