Full-on coding on your phone, zero setup.

Katydex is a code editor for Android with Linux built in. Python, Node.js, PHP, C, C++, Java, a full terminal, and SQLite in one app.

shop $python hello.py

Hello, Katydex!

Download APK Take the tour

Supported languages

01/ 09Terminal

A full terminal.

Colors, a cursor, and full-screen programs.

Download

shop $ node -v

v24.18.1

shop $ python -V

Python 3.14.8

shop $ php -v

PHP 8.4.26 (cli)

shop $ java Cart.java

Total : 67100

Change : 32900

shop $ gcc change.c && ./a.out

Change : 32900

shop $ python hello.py

Hello, Katydex!

shop $

02/ 09Languages

Six languages. One Run button.

All installed from the start.

Python 3.14Node.js 24PHP 8.4C / C++ Clang 22Java 17SQLiteHTML · CSS · JSBash

Web & PHP

A PHP server runs inside the app.

Python

Run a script and see the result right away.

Node.js

JavaScript runs inside the app.

Demo

report.php

Editor + Preview

Run

1<?php

2// Sales report

3date_default_timezone_set("Asia/Jakarta");

4$revenue = 0;

▥

Reportcreated Oct 9, 2026

Revenue$1,342

Orders12

Average$111.83

Best sellers

Fried Chicken14 sold

French Fries9 sold

Chicken Noodles7 sold

Fried Rice7 sold

Iced Latte6 sold

ProjectEditorTerminalDatabase

report.py

Editor + Terminal

Run

Pyreport.py×

1import json

2data = json.load(open("products.json"))

3total = sum(p["price"] for p in data)

4print("Items :", len(data))

5print("Value :", total)

$ python report.py

Items : 12

Value : 186000

Finished · exit 0 · 0.21 s

ProjectEditorTerminalDatabase

app.js

Editor + Terminal

Run

JSapp.js×

1const products = require("./products.json");

2const total = products.reduce((a, p) => a + p.price, 0);

3console.log("Items :", products.length);

4console.log("Total :", total);

$ node app.js

Items : 12

Total : 186000

Finished · exit 0 · 0.14 s

ProjectEditorTerminalDatabase

SQLite

Create, edit, and drop tables with one tap.

Java

Compile and run in one tap.

C / C++

Clang and GCC are already included.

Demo

dbshop.db×

item×products+

SELECT * FROM "item" LIMIT 100;

Run

31 rows · 15 ms

ORDERPRODUCTQTYPRICE

TRX-0001322.50

TRX-0001511.20

TRX-0002141.80

TRX-0002210.90

TRX-0003432.10

TRX-0004322.50

TRX-0004610.80

TRX-0005221.80

TRX-0005110.90

TRX-0006533.60

TRX-0007410.70

TRX-0007322.50

ProjectEditorTerminalDatabase

Cart.java

Editor + Terminal

Run

JCart.java×

1var k = new Cart();

2k.add("Fried Chicken", 2, 25000);

3k.add("Iced Tea", 1, 5000);

4System.out.println("Total : " + k.total());

$ java Cart.java

Total : 67100

Change : 32900

Finished · exit 0 · 2.17 s

ProjectEditorTerminalDatabase

change.c

Editor + Terminal

Run

Cchange.c×

1#include <stdio.h>

2int main(void) {

3 int total = 67100, paid = 100000;

4 printf("Change : %d\n", paid - total);

$ gcc change.c && ./a.out

Change : 32900

Finished · exit 0 · 0.38 s

ProjectEditorTerminalDatabase

One APK file

No Termux and no extra apps.

±45

seconds of setup

Only on first launch.

03/ 09Editor

An editor that helps.

Writing code on a small screen isn't easy. These four things make it lighter.

04/ 09Projects

Your project, tidy in one tree.

Create, rename, move, copy, and delete files without leaving the app.

Your files stay yours.

Still there if Katydex is uninstalled
Opens in file managers and other apps
Easy to copy to a computer or back up

05/ 09Appearance

Tune it until it's easy on your eyes.

This is a copy of the app's Appearance screen. Tap a theme: this page changes with it.

2 themes
Display scale 50–150%
Text size 10–22
Your own code font
English and Indonesian

Try it right here

Appearance

Theme

Display scale

Code font

Font file…

Text size

print("Hello, Katydex")
SELECT * FROM menu;

06/ 09Numbers

Numbers from real phones.

We measured every one of these ourselves. None are estimates.

439MB

One APK file

Six languages, the C/C++ and Java compilers, and Linux itself are all inside.

9seconds

Six languages back to back

Run by a single test script, in 9 to 13 seconds.

0.4seconds

A sample Python script

How long the program runs after you tap Run.

2phones

Tested from a clean install

Two different brands, both on Android 16.

Measured October 9–10, 2026 on two test phones: Infinix X6870 and realme RMX5303. Results on other phones may differ.

07/ 09No Termux

No Termux. See the difference.

The usual way to run code on Android takes two apps and a handful of commands. Katydex cuts it down to three taps.

Editor + TermuxKatydex

Apps to installTwo or moreOne

Setup commandspkg update, pkg install …None

Running codeSwitch apps, then type a commandA Run button

Web and PHP previewStart your own serverBuilt in

Viewing SQLite dataFrom the command lineA table on screen

Already happy with Termux? It's still a great choice. Katydex is for people who want to start writing code right away.

08/ 09Specs

Check before you download.

So there are no surprises after installing.

SystemAndroid 8.0+

Proven on Android 16.

ProcessorARM 64-bit

The standard on today's phones.

Download439 MB

One download, nothing more to fetch later.

Free space±2 GB

The built-in Linux uses about 1.1 GB.

InternetNot required

You can write and run code offline.

RootNot needed

Runs on an ordinary phone.

AccountNot needed

Open the app and start.

Ads and trackersNone

Code runs on your phone, not on a server.

Permissions it asks for

All files access requiredSo projects are saved as ordinary files in the IDEWorkspace folder.
InternetUsed when a web preview loads content from the internet and when you install extra packages.
Run in the background optionalSo a running program isn't paused when you leave the app.

Good to know

Version 0.3.0. Early days, and it gets better with every update.
Proven on Android 16 across two phone brands. Built for Android 8.0 and up.
A direct APK download. No app store account needed.
Code suggestions come from language servers running on your phone, offline. They read your code, so they know what is in your lists, modules and your own functions.
Some phones pause background apps. One button in Settings asks Android to keep Katydex running.

09/ 09FAQ

Still have questions?

Seven questions most likely to come up before installing.

Is Katydex free?

Yes. There are no accounts, ads, or trackers in it.

Do I need Termux or root?

Neither. Katydex's built-in Linux runs on an ordinary phone, with no root and no extra apps.

Why is it 439 MB?

Because every language ships inside the file: Python, Node.js with npm, PHP, Java, the C and C++ compilers, and the language servers behind the code suggestions. In return, there is nothing else to download once it is installed.

Why does it ask for all files access?

Projects are saved as ordinary files in the IDEWorkspace folder, not inside the app. That is why your projects survive uninstalling Katydex and still open in other apps.

Do I need internet?

Only to download the APK. After that you can write and run code offline. The internet is used again only when you install extra packages or when a web preview loads something from the internet.

Can I add libraries or other tools?

Yes, from the terminal. The built-in Linux is Alpine, so you install packages with apk add (needs internet). npm comes built in.

Do programs stop when I leave the app?

Some phones pause apps in the background. Settings has a button that asks Android not to restrict Katydex. Results vary from phone to phone.

End of the tour

Tour's over. Your turn.

Three taps from here to your first running code.

Tap 1DownloadOne APK file, installed like any other.

Tap 2AllowOne file-access switch and you're in.

Tap 3RunWait for the one-time setup, write code, then press Run.

Download Katydex.apk

FreeVersion 0.3.0439 MBAndroid 8.0+ · ARM 64-bit

PythonNode.jsPHPC / C++JavaSQLiteFull terminalNo accountNo Termux

New in version 0.3.0: a new look, smart code suggestions for JavaScript, TypeScript, Python, HTML, CSS, C, C++ and PHP, and npm built in.

SHA-256: 5793e0a513edd31046dcf0e02df7ed7f1d2d021405e1e9a8ab521f18f113a390

Have version 0.2.0 or older? Uninstall it first, then install the new one: from 0.3.0 on, Katydex is signed with a new key. Your projects in the IDEWorkspace folder stay safe.

Download Katydex Insider · 439 MB

Test version 0.3.0-beta.1, with the newest features. It may contain bugs. It installs next to Katydex.