Problem scenario
You are not sure if you have valid JSON or not. You have converted raw logs of an application to be in JSON format. There is a flat file receiving what you believe to be valid JSON. How do you know for sure?
Solution
Put the JSON in here https://jsonformatter.curiousconcept.com/ and click "Process".
The JSON should start with an opening brace { and end with a closing brace }. The final element should not have a comma. You can copy some JSON and put it inside two braces {} and remove the final comma (if any exists) from your logs, text or file you are creating. Then above website will tell you if you have valid JSON.