For debugging purpose, I log network traffic and save it as a HAR file. When the resulting HAR file is large ( > ~12Mb ) it's content is truncated, resulting an Invalid JSON object.
* Disclaimer: This answer is from the developers of HttpWatch *
I'm not sure why you are seeing HAR file truncation but you could try using HttpWatch:
It does not have a limit on the size of the output HAR file and can also record in a more compact HWL file format.
This may not be the solution for everyone, but I've just checked that Opera v56 allows HAR file that contains a JSON object that is 1.1MB.
Chrome and Firefox both truncated the same JSON data object.
However that overall HAR output file from Opera somehow also accumulated to a very large size of 221MB.
Just strange behavior on my Chrome 80 on Ubuntu: HAR file wrote fast first 8MB (in this case file truncated), after that file continue writing very slow (~1MB in minute) and go to 75MB (in my case) in hour or more.
