Logging libraries. See also other tools for development, and a tutorial on logging and debugging. There's an article on Common Lisp and Logging, which discuss the ecosystem and general requirements for loggers in Common Lisp.

  • a-cl-logger - A common lisp logging library providing context sensitive logging of more than just strings to more than just local files / output streams
  • cl-grip - cl-grip is a high-level logging system for Common Lisp, focusing on a clear user interface, support for flexible structured logging, and easy extensibility for different backends to support direct logging to various inputs
  • cl-log - CL-LOG is a general purpose logging utility, loosely modelled in some respects after Gary King's Log5
  • cl-syslog - Common Lisp interface to local and remote Syslog facilities
  • flood - Comfortable, powerful and tiny logging library for common lisp
  • hu.dwim.logger - hu,dwim,logger is a logging library
  • irc-logger - irc-logger is a networking library written by Kevin Rosenberg which uses the cl-irc library to provide multichannel Internet Relay Chat (IRC) logging
  • journal - A library for logging, tracing, testing and persistence
  • Log4CL - Log4CL is high performance extensible logging library for Common Lisp
  • log5 - Log5 is a logging library organized around five things: categories, outputs, senders, messages and contexts
  • LoGS - A programmable log analysis engine available under the terms of the GPL
  • logv - Logv is a cognitively lightweight logging utility for Common Lisp
  • Verbose - Verbose is a logging framework that aims to provide a good default setup as well as an extensible back-end to suit all your logging needs
  • vom - A tiny logging library for Common Lisp

When in doubt, you can go with log4cl, the "de facto" logging library maintained by the Sharplispers community. Or have a look at the Comparison of Common Lisp Logging Libraries, which is fairly extensive (last updated in 2016).