A GUI JavaScript Operating System For The ESP32

Haris16-code / KryonOS

KryonOS is an ESP32 GUI operating system with a JavaScript runtime for apps. It provides a real touch-based interface and allows installing and running JS apps dynamically without reflashing firmware.

KryonOS

KryonOS is an open-source, lightweight, high-performance GUI Operating System and JavaScript App Runtime designed specifically for the ESP32 microcontroller. It provides a complete desktop-like experience on embedded devices, featuring an integrated JS engine (Duktape) for executing standalone JavaScript applications, double-buffered graphics for smooth 2D/3D rendering, an App Store, file management, and direct hardware API access.

ESP32 + ILI9341 2.8" (Touch)	Multiple Devices (Lab Overview)	M5Stack Cardputer	CYD (Cheap Yellow Display)	LilyGO T-HMI
Stable 🟢	Experimental 🧪	Experimental 🧪	Experimental 🧪	Experimental 🧪

Features

• JavaScript App Runtime: Execute interactive JS apps natively on the ESP32 using the optimized Duktape engine.
• Rich UI & Graphics: Built-in graphics library with double-buffering support for smooth, tear-free 2D and 3D rendering.
• App Store & Installer: Browse, download, and install JavaScript apps and updates dynamically over Wi-Fi.
• File Management: Fully functional file explorer and text editor utilizing the SD Card for storage.
• Hardware API:…

View on GitHub

Meet KryonOS: An Open-Source Graphical OS and JavaScript Runtime for the ESP32

Microcontrollers have advanced far beyond simple sensor telemetry and blinking LED loops. With dual-core 240MHz processors and high-speed external PSRAM, modern chips like the ESP32 and ESP32-S3 can run full-fledged operating environments. That vision led to KryonOS: an open-source graphical operating system featuring an embedded JavaScript application engine, native 3D hardware graphics, and modern networking capabilities.

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ESP32 + ILI9341 2.8" (Touch)	Multiple Devices (Lab Overview)	M5Stack Cardputer	CYD (Cheap Yellow Display)	LilyGO T-HMI
Stable 🟢	Experimental 🧪	Experimental 🧪	Experimental 🧪	Experimental 🧪

Why an OS on a Microcontroller?

Typically, developing for an ESP32 requires flashing monolithic firmware via PlatformIO or the Arduino IDE for every tweak. Changing a button's position or tweaking game logic means a full recompile and reflash cycle.

KryonOS shifts this paradigm by establishing a clear boundary between the native C++ core kernel and high-level applications:

• Native C++ Kernel: Manages FreeRTOS task scheduling, display SPI DMA channels, touchscreen interrupts, power management, and storage partitions.
• Embedded JavaScript Engine: Runs isolated user applications dynamically loaded from an SD card or internal LittleFS flash without recompiling firmware.
• Unified System APIs: Gives developers high-level JavaScript access to graphics primitives, networking, audio, file storage, and hardware sensors.

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Hardware-Accelerated 3D on a Microcontroller: The Kryon3D Engine

A flagship highlight of KryonOS is Kryon3D, a native C++ rasterization pipeline exposed directly to the JavaScript runtime. Built for double-buffered, tear-free rendering on TFT displays (like the ILI9341), it handles the heavy math at bare-metal speeds:

• Hardware Shading & Lighting: Directional lighting calculations and backface culling to maximize polygon throughput.
• FastMath Acceleration: Vector, matrix, and trigonometric operations offloaded to native routines for 30–60 FPS scene updates.
• Composite 2D + 3D Rendering: Render a 3D scene (cubes, wireframe meshes, or billboards) and composite 2D HUD text, crosshairs, or mini-maps directly in the same frame buffer before a single DMA flush to the display glass.
• Distance Fog & Camera Models: Standard 3D world coordinates with 6-DOF camera controls and fog blending.

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Modern Networking: Full REST, Streaming, and WebSockets

Connected IoT and handheld devices need reliable communication without blocking the UI. KryonOS implements a non-blocking network architecture that avoids Task Watchdog (TWDT) panics and handles memory safely:

• Complete REST API: Native Network.get(), post(), put(), delete(), and request() bindings with configurable timeouts.
• Memory-Optimized TLS: Uses Maximum Fragment Length Negotiation (MFLN) to drop mbedTLS buffer usage from 32 KB down to ~3 KB, leaving internal SRAM free for execution.
• Direct Storage Streaming: Network.downloadFile() streams remote files into LittleFS or SD storage in 1024-byte chunks with real-time download progress callbacks, preventing heap exhaustion.
• W3C-Standard WebSockets: Native C++ engine with automated 20-second ping/pong frames to keep NAT connections alive for live telemetry and IoT dashboards.
• Smart Wi-Fi Manager: Multi-network persistence (known_networks.json) with RSSI sorting, automatic failover, and lightweight WAN reachability verification.

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Sample: Running a 3D Scene in JavaScript

Writing an application for KryonOS is straightforward for anyone familiar with basic JavaScript:

// Initialize 3D Viewport in PSRAM
if (Kryon3D.begin(240, 320, 16)) {
    Kryon3D.setCamera(0, 2.0, -4.0, 0, 0, 0, 60);
    Kryon3D.setLight(0.5, 1.0, -0.7, 0.3, 0.7);

    var angle = 0;

    while (true) {
        Kryon3D.clear(0x0000); // Clear buffer

        // Draw a rotating lit 3D cube
        angle += 0.05;
        Kryon3D.drawCube(0, 0, 0, 1.5, 1.5, 1.5, angle, angle * 0.5, 0, 0xFD20, true);

        // Draw 2D HUD over 3D scene
        System.drawString("FPS: 30", 10, 10, 2);

        // Push frame to physical glass (Zero Flickering)
        Kryon3D.render(0, 0);

        System.delay(16);
    }
}

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Hardware Support: Stable vs. Experimental Boards

KryonOS is built to support a range of popular maker hardware, with clear milestones across devices:

• ESP32 + ILI9341 2.8" SPI Touch: The flagship reference platform with full, battle-tested Stable support.
• ESP32 Cheap Yellow Display (CYD): While we ran experimental builds of KryonOS v1.0.0 during internal lab testing, those were not published as standalone binaries. With v2.0.0, CYD is officially supported with a fully tested, stable binary ready to flash directly to your board.
• M5Stack Cardputer & LilyGO T-HMI: Currently in active Experimental status as we optimize key layouts and display bus timings.

Check out the repository, run the code on your own hardware, or leave a star to follow along with the upcoming v2.0.0 release!

Explore the KryonOS GitHub Repository

Haris16-code / KryonOS

KryonOS is an ESP32 GUI operating system with a JavaScript runtime for apps. It provides a real touch-based interface and allows installing and running JS apps dynamically without reflashing firmware.

KryonOS

KryonOS is an open-source, lightweight, high-performance GUI Operating System and JavaScript App Runtime designed specifically for the ESP32 microcontroller. It provides a complete desktop-like experience on embedded devices, featuring an integrated JS engine (Duktape) for executing standalone JavaScript applications, double-buffered graphics for smooth 2D/3D rendering, an App Store, file management, and direct hardware API access.

ESP32 + ILI9341 2.8" (Touch)	Multiple Devices (Lab Overview)	M5Stack Cardputer	CYD (Cheap Yellow Display)	LilyGO T-HMI
Stable 🟢	Experimental 🧪	Experimental 🧪	Experimental 🧪	Experimental 🧪

Features

• JavaScript App Runtime: Execute interactive JS apps natively on the ESP32 using the optimized Duktape engine.
• Rich UI & Graphics: Built-in graphics library with double-buffering support for smooth, tear-free 2D and 3D rendering.
• App Store & Installer: Browse, download, and install JavaScript apps and updates dynamically over Wi-Fi.
• File Management: Fully functional file explorer and text editor utilizing the SD Card for storage.
• Hardware API:…

View on GitHub

Support KryonOS

If you find KryonOS useful and want to support its development, you can contribute toward new hardware, testing, and support for additional boards.

Support KryonOS