Redmine

cf_x: get issues with the given value for custom field with an ID of x. (Custom field must have 'used as a filter' checked.)

I tried to filter issues by custom field and initially I tried to put only this filter in the URL. I issued the following request on my Redmine instance:

http://hq.company.com.br/redminetest/issues.xml?cf_24=1&limit=25&key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

The query above fetch all the issues on my instance, regardless of the custom field 24's value.

http://hq.company.com.br/redminetest/issues.xml?project_id=176&cf_24=1&limit=25&key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

The query above works perfectly, filters by project and by custom field.

The REST is only working properly if there is a project filter together with the custom field filter, it doesn't work alone.
My field is marked with 'use as filter' only.