gforth - GNU Forth for Android

229 reviews
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About this app

Gforth is the GNU's project implementation of the programming language Forth. This APK is the binary distribution for the Android platform, for ARM and x86-processors. You can find more information and links to source code on, and more information about Android-specific features on

For optimum experience when programming, use a soft keyboard made for that task, like Hacker's Keyboard.

Gforth is available under GPLv3.

Gforth uses GCC to compile a fast direct or indirect threaded Forth; Gforth is fully ANS-Forth and Forth-2012 compliant. Authors of Gforth are Anton Ertl, Bernd Paysan, Jens Wilke, Neal Crook, David Kühling and others.

The goal of the Gforth Project is to develop a standard model for ANSI Forth. This can be split into several subgoals:

* Gforth should conform to the ANSI/200x Forth standard.
* It should be a model, i.e. it should define all the implementation-dependent things.
* It should become standard, i.e. widely accepted and used. This goal is the most difficult one.

To achieve these goals Gforth should be

* Similar to previous models (fig-Forth, F83)
* Powerful. It should provide for all the things that are considered necessary today and even some that are not yet considered necessary.
* Efficient. It should not get the reputation of being exceptionally slow.
* Free.
* Available on many machines/easy to port.

The Gforth apk installs three icons: One is the fast engine (Gforth fast), one the debug engine (Gforth ITC), where the single step debugger works, and the backtrace is precise even on exceptions, and the third one is the net2o protocol demo app, with the "Nettie" octopus. It's a demo now, so don't expect it to work flawless.
Updated on
Aug 29, 2022

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229 reviews
Alan Squire
June 11, 2021
It works. (1) Would be nice to be able to change font size (2) I can't paste anything into the editor using long press... Also, consider adding options like "Use volume down key for CTRL"; that way, we wouldn't have to install outdated keyboards like Hackers Keyboard, which doesn't work well on all systems.
6 people found this review helpful
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Yann Vernier
July 4, 2022
Provides GNU Forth, but has some glitches. I've found: 1. Although I've granted it Storage permission, it doesn't see the contents of /sdcard. Its storage is under /sdcard/Android/data/gnu.gforth/files. 2. It crashes when external hardware keyboard connects; if it was already connected when starting, it can be used. This poses a problem e.g. when switching to the app after the keyboard falls asleep. 3. The font used is limited (e.g. no Swedish åäö), and terminal may lag. 4. g does nothing.
2 people found this review helpful
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A Google user
February 3, 2019
Latest January upgrade broke the system. Forth crashes during start-up on Android 4.4.2 . Any option of downgrading so that I can still enjoy this excellent system ?
2 people found this review helpful
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Bernd Paysan
July 26, 2019
You can download past versions on

What's new

Polishing to get much closer to Gforth 1.0