Problem Definition

Currently , there's no way to filter issue using email domain . It can often be helpful to search for all issues reported by a reporting user's email domain, perhaps not so much w/AOL or gmail, but certainly with corporate domains. Please enable either the contains operator for reporter or add a function to get email domain from reporter or similar solution.

Suggested Solution

Provide a JQL query , for example :-

reporter in emaildomainOf("customer1.com") ...

Workaround

Workaround 1:

1. Go to Jira settings > Issues > Custom fields > Add custom field;
2. Click on 'All' and search for the field type Domain of reporter;
3. Select this field type > give this field a name (let's call it reporterDomain);
4. Confirm the field creation (this field doesn't need to be added to any screen);
5. Use this field to search using JQL. Example:

   reporterDomain = 'somedomain.com'
   

Since 01 Oct 2021, support for JQL clauses o on custom field types "Domain of reporter" and "Domain of assignee" has been removed and hence this workaround is no longer applicable. JQL queries using such clauses will no longer be valid.(See announcement here)
See the workaround using Automation below.

Workaround 2 (with Automation)
Taken from this post with thanks to its creator:

1. Create a new custom field using Short text (plain text only) type and associate it with the service project. (I named mine "Reporter Domain")
2. Create an automation rule to run When: Issue Created >>> Then: Edit issue fields and for my example provide the field name "Reporter Domain" and set the value to {{ reporter.emailaddress.substringafter("@") }}
3. Turn the automation rule on and then any newly created issues should populate the field with the domain name of the reporter's email address.
4. Filtering with JQL expressions can now be done on this field type with:

"Reporter Domain[Short text]"~'email_domain.com'