Power JSON Editor is a powerful JSON editor for developers. Using Power JSON Editor, developers can easily import JSON data from the Web, import PLIST data as JSON, or export JSON to a PLIST file. With support for plug-ins, Power JSON Editor's functionality can easily be extended. It currently supports rendering JSON data with the Jade template.
v2.1 
Power JSON Editor supports Apple Silicon Macs natively now!
Other improvements:
1. New option to add a line break at the end of JSON when saving the file
2. New option to disable macOS autosave feature
 
                             
                            Blinged JSON Validator is a free app to validate JSON files with syntax highlighting, whitespace indentation, error messaging, and hotkeys.