Playback – Interactive Programming and Print Debugging Reimagined

In plain words

Playback is an open-source debugging tool for Clojure and ClojureScript that replaces traditional print debugging. It tags and traces code forms, sending them to tap> and Portal for visualization. The tool automatically replays functions on evaluation, instantly re-renders results, and integrates traced data directly into the REPL. It's designed for Clojure developers seeking more interactive and efficient debugging workflows.

written from the facts on this page · September 2026

From the sources

Easier-than-print dataflow tracing to tap> and Portal with automatic last-input function replay on eval, instant re-render and effortless extraction of traced data - gnl/playback

In the maker’s words, at launch

Ladies and gentlemen of a Lisp persuasion, Clojurians and Clojuristas, followers of the paren and everyone else covetously eyeing the greener grass, I made an open-source thing that I would like to share with you. My elevator pitch is that it'll make you forget all about regular print debugging in 10 minutes…

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