An effortless 'ndjson' (newline-delimited 'JSON') logger, with two primary log-writing interfaces. It provides a set of wrappings for base R's message(), warning(), and stop() functions that maintain identical functionality, but also log the handler message to an 'ndjson' log file. 'loggit' also exports its internal 'loggit()' function for powerful and configurable custom logging. No change in existing code is necessary to use this package, and should only require additions to fully leverage the power of the logging system. 'loggit' also provides a log reader for reading an 'ndjson' log file into a data frame, log rotation, and live echo of the 'ndjson' log messages to terminal 'stdout' for log capture by external systems (like containers). 'loggit' is ideal for Shiny apps, data pipelines, modeling work flows, and more. Please see the vignettes for detailed example use cases.