I’ve often used the jsonlines format for application logging, though I didn’t have a name for it until today.

I appreciate this format because, as a log file, I can use all of my standard tools to work with it (grep awk etc.). Since it’s a text file, I can use standard text editors to view and search the contents.

Since my application is the one that’s creating the log file, newlines will not appear or will be escaped.

I can often accomplish my goal without parsing the objects, but when I need to, I can break out powerful tools like `jq` or RecordStream to query the contents in a structured way. I can also treat the log file as a streaming or archived data source and process it using database technologies like Redshift or Elasticsearch.

I can’t think of another format that would be more convenient. I have worked with log file formats that are actual XML or JSON documents, and they are inconvenient in practice. I can’t think of another format that would be more convenient than this one for structured application logging.

Lots of other tools work on a line by line basis.

But newlines can't appear in JSON-Lines which is what this is really based off of.