Noticed that since November update, loggly.log("message", error) when error=undefined breaks where it shouldn't (I guess). Offending line: https://github.com/winstonjs/winston-loggly/blob/ff56088b4cf76fd00724ebab3cfe37f2ab66276a/lib/winston-loggly.js#L116 See related issue on Winston: https://github.com/winstonjs/winston/issues/947 Can PR if you confirm.