REBL is a graphical, interactive tool for browsing Clojure data and features:

  • a two-pane browser/viewer system for viewing collections and their contents
  • navigation into and back out of nested collections
  • a structured editor pane for entering expressions to be evaluated
  • a root browse of a history of expression evaluations
  • the ability to 'wrap' a stdio based REPL (e.g. Clojure's native REPL) so that it can monitor and display the interactions therein, while still allowing them to flow back to the host (e.g. the editor)
  • when used with non-stdio repls (e.g. nREPL), can be launched a la carte and accepts values to inspect via an API call
  • the ability to capture nested values as defs in the user namespace
  • the ability to run multiple independent UI windows
  • metadata viewing
  • datafy support
  • extensibility to new browsers and viewers
  • full keyboard control via hotkeys

REBL runs in your application JVM process, and can be used at dev-time without adding any runtime deps. The UI is written in JavaFX.

The REBL Readme provides information on installation and usage of REBL.

Download REBL

To download REBL, please read and agree to the EULA terms specified below.

REBL End User License Agreement (EULA)

REBL is provided under the terms of this license, and is protected by copyright and/or other applicable law. Any use of REBL other than as authorized under this license or copyright law is prohibited.

By exercising any rights to REBL, you accept and agree to be bound by the terms of this license. To the extent this license may be considered to be a contract, Cognitect Inc, a Delaware Corporation, grants you the rights contained here in consideration of your acceptance of such terms and conditions.

If you do not wish to accept these terms, you should not download, install, or use REBL.

Cognitect Inc, a Delaware Corporation, is the owner of all copyright and intellectual property rights in REBL and grants you a personal, worldwide, royalty-free, perpetual, non-assignable, and non-exclusive license to use REBL under the terms and conditions contained in this license.

You may not use REBL for commercial use (e.g. at or for work) unless:

a) You are an active, paying customer of Datomic (Cloud or On-Prem)

-- OR --

b) You are an active subscriber of the REBL Patreon

You may not redistribute REBL.

Cognitect owns and will retain all legal rights in the software, including all copies, alterations, derivatives or modifications of REBL.

REBL is licensed, not sold or given away.

Representations, Warranties and Disclaimer

Unless otherwise mutually agreed to by the parties in writing, licensor offers the work as-is and only to the extent of any rights held in the licensed work by the licensor. The licensor makes no representations or warranties of any kind concerning the work, express, implied, statutory or otherwise, including, without limitation, warranties of title, marketability, merchantibility, fitness for a particular purpose, noninfringement, or the absence of latent or other defects, accuracy, or the presence of absence of errors, whether or not discoverable. Some jurisdictions do not allow the exclusion of implied warranties, so such exclusion may not apply to you.

Limitation on Liability.

Except to the extent required by applicable law, in no event will licensor be liable to you on any legal theory for any damages, including direct, indirect, special, incidental, consequential, punitive or exemplary damages arising out of this license or the use of or inability to use the work (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if licensor has been advised of the possibility of such damages.


This License and the rights granted hereunder will terminate automatically upon any breach by you of the terms of this License.

The use of REBL is governed by the terms of the REBL EULA. By downloading REBL, you are agreeing to those terms.