SharePoint Search Query Tool
Use this tool to test out and debug search queries against the SharePoint 2013/2016/SPO Search REST API.
Learn how to build an HTTP POST query, and how the different parameters should be formatted.
After running the query, you can view all types of result sets returned; Primary Results, Refinement Results, Query Rules Results, Query Suggestions, in addition to the actual raw response received from the Search service.
Can be used to query both SharePoint 2013/2016 On-Premise
, and SharePoint Online
More about the Search REST API in SharePoint 2013 on Nadeem's blog: