gforth - GNU Forth for Android

248 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
Dec 8, 2023

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Ratings and reviews

195 reviews
John Cochran
April 4, 2024
Nice implementation. However, it seems that all output is buffered and nothing will be displayed until execution is finished. Have attempted to flush the output during execution and nothing works. When the main word finally returns, all of the output is immediately displayed. So, everything is stored until execution is finished and then everything (up to thousands of lines) gets displayed as one huge chunk.
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Amila Praveen
February 10, 2024
I really enjoy stack languages! We are fortunate to have open source full ANS Forth GForth! 1. The phone is Android 11, why there is no GForth folder anywhere on sdcard, or anywhere i can put files into? After installing i gave storage permission, and Gforth said successfully created the gforth folder, but i see no such folder! 2. Please consider porting GForth 0.7.9 for Termux, the current version there is still 0.7.3 which is rather buggy. GForth works so well on Termux than in a separate app!
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N. A. McBee
November 14, 2023
Developer replies on critical comments, that's helpful! So I found out what went wrong and give it 5 stars now. Nevertheless, you must tame your keyboard app of choice to behave in a way which Gforth can handle. All these automatic things are prone to erratical behavior, esp. automatic punctuation and cousins. Programming on the phone is simply cumbersome. But maybe you have a nice Forth application which you may transfer to the phone and use it. This should work fine.
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Bernd Paysan
November 16, 2023
The keyboard of choice for Gforth is Hacker's Keyboard. Even better is when you have a Bluetooth keyboard, i.e. a real one.

What's new

Updating to current Gforth snapshot