Software that is specifically made to run on an Ultimate Device. Meaning a 1541Ultimate, Ultimate II+, Ultimate Elite, or a Commodore64 Ultimate.

• chrisgleissner/c64bridge - MCP server to control and program the Commodore 64 Ultimate, Ultimate 64, Ultimate II, or VICE.
• xphileby/c64u-mcp-server - MCP (Model Context Protocol) server for the Commodore 64 Ultimate Computer.
• bbsbot/ultimate-64-dev - A library of Claude Code skills to empower the ultimate Commodore 64 developer for games, utilities, and more.
• MCP server for the Ultimate 64 series ! Version 0.1 Alpha ! - A Model Context Protocol (MCP) server for the Commodore 64 Ultimate — the official modern Commodore 64 computer. This server enables AI assistants like Claude, ChatGPT, and Cursor to control your C64 via the Ultimate's REST API.

• robbiew/turbo64 - A modern Commodore 64 BBS written in C for the Oscar64 compiler. Optimized for VICE and the C64 Ultimate.
• nmclaren/c64u-term - Terminal software targeted primarily for the Commodore 64 Ultimate by Commodore International Inc. May or may not work on other devices.

• UBoot64-v2 - Boot manager/Boot menu for Ultimate devices.

• MykelSIlver/meshchat64 - End-to-end-encrypted WebSocket chat running entirely in 6502 assembly on a Commodore 64. A real C64 (or Ultimate-64) chats, fully encrypted, in the same network as modern browsers.

• Infinite Matter
• Ultiverzum
• The Tuneful Eight (included on The Very Second)
• UltimateDemo2026
• Raster Split Fun

• rericflores/c64uhex - C64UHEX is a native hex editor for the Commodore 64. It provides professional, byte-level inspection and modification of binary data using a true PETSCII interface, respecting the constraints and character semantics of the original platform.
• drericflores/AdveditC64 - Advanced Commodore Editor is a native, full-screen text editor designed specifically for the Commodore 64, with special attention given to the C64 Ultimate and its SD/USB-based storage workflow. The editor is inspired by the philosophy of the Linux nano editor: Simple controls, fast interaction, minimal cognitive overhead, and clear on-screen prompts while respecting the technical constraints and historical behavior of vintage hardware.

• qwertybob1978/Commodore64_8088_Ultimate_Emulator - PCem Inspired 8088 Emulator for the Commodore 64 Ultimate (in Turbo mode)

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  Ultimate Opus

  Ultimate Opus - A dual-pane file manager for Ultimate devices, released by Lft. Current version is 0.2, released in 2014. No active development.

• Axlfc/abadia-c64-starter - Test Port for Commodore 64 (Ultimate) of the game 'La Abadía del Crimen'

• Cenbe/geoIRC - IRC client for GEOS/GDOS64. Connect to any IRC channel available on the internet. Only works via Ethernet!
• xahmol/GeoUTools - Tools for use with Ultimate devices without having to leave the GUI, or even having to open the Ultimate menu! Also works in 80-column mode in GEOS128 with Ultimate cartridge.

• ALBERT - Win/Mac/Linux application to create C64 graphics; it can send its images to your Ultimate device, save them as .PRG and other formats. ALBERT allows its users to create Commodore 64 images that extend into the left and right borders of the visible screen, with sprites to display the extra pixels, using an uncomplicated drawing workflow, without requiring the assistance of a coder.

• JKnivesworthy/hometo64 - A Home Assistant Integration to view and control your home directly from the Commodore 64 Ultimate.

• jbramwell/READYCode - A remote editor for the Commodore 64 Ultimate.

• kfox/c64cast - Turn a real Commodore 64 into a programmable display + audio device via Ultimate 64 or TeensyROM+ — video, SID-music scopes, webcam, MIDI/ASID synth, WLED, generative visuals, overlays, playlists.

• Heartbeat Sound Tracker - Heartbeat Soundtracker is currently the only music program that fully covers the sound capabilities of Commodore 64 Ultimate – all 8 SIDs and 7 sampler channels.
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  Ultimate 64 Web Music Player on a mobile device

  Ultimate 64 Web Music Player - Use any device with a web browser to play your favorite SID songs at home. Designed to be used with your mobile phone to have an easy way to control the music that is coming out of your C64 or C64U.

• Ultimate64 SID Player (Windows/Mac/Linux) - Play SID music files from your Commodore 64 Ultimate, Ultimate64, or Ultimate-II+ via the REST API.
• Ultimate64 SID Player (Amiga) - Ultimate64 SID Player is a full-featured C64 SID music player for AmigaOS that connects to Ultimate64 and Ultimate-II devices over the network. It provides playlist management, multi-subsong navigation, and integrates with the HVSC song length database for accurate playback timing.
• Phosphor - A SID music player for USBSID-Pico hardware, software-emulated SID, and for Commodore Ultimate 64 network playback. Includes a library panel for finding music online off the HVSC website.

• fputmango/Teletext64U - Teletext program showing live pages from the internet for the Commodore 64 Ultimate and other Ultimate products that have networking capabilities. Also supported: WiC64!
• k6lcm/c64u-radar - an ADS-B radar scope for the Commodore 64 Ultimate

• xlar54/uos-master - A new graphical OS made specifically to take advantage of the Ultimate 64's capabilities
• ReadyOS - What if a Commodore 64 could feel ready, not just nostalgic? ReadyOS treats waiting as the enemy. It is a keyboard-first, full-screen terminal-style environment built around instant app switching, suspend/resume, shared clipboard and history, and deeper links between apps.
• Command64 OS - MS-DOS style operating system for the C64 with a REU size of 1MB minimum

• danielwcarey/C64UltimateMouse - Sample code to use the Commodore 64 Ultimate Mouse

• xlar54/ultimateii-dos-lib - cc65 library for accessing the DOS and network functions of the Ultimate II+ cartridge the Ultimate 64 motherboard, and the new Commodore 64U
• omiq/c64-ultimate - Programming the C64 Ultimate
• c64uploader/go-ultimate - A Go library for remotely controlling Commodore 64 Ultimate
• monteslu/c64lua - Write Commodore 64 games in PICO-8-flavored Lua, compiled to native 6510. Autostart .d64 disks for the C64 Ultimate and demo scene.

• EdyJ/c64u-control-panel - Comprehensive web-based control panel and toolset for the Commodore 64 Ultimate (C64U)
• amiantos/c64-ultimate-toolbox - Native macOS app for streaming, viewing, and controlling your Commodore 64 Ultimate device with real-time CRT shader effects.
• chrisgleissner/c64commander - Cross-platform app (Android/iOS/web) for controlling a Commodore 64 Ultimate over your local network.
• Ultimate64 Manager - A cross-platform desktop application for managing Commodore 64 Ultimate, Ultimate 64 Elite, and Ultimate-II+ devices. Browse files, stream content, play SID music, mount disk images, and configure device settings. Also, 'Memory Editor', you can now peek and poke C64 memory directly from your desktop.
  • Amiga OS version
  • iPhone version
• sandlbn/Phosphor - A SID music player for USBSID-Pico hardware and Commodore Ultimate 64, supporting both hardware SID chips and emulated SID playback.
• svetzal/r64u - Cross-platform desktop app for controlling Commodore 64 Ultimate devices (Ultimate 64 / 1541 Ultimate II+) over the local network — browse files, mount disks, run programs, play SID music.
• coat64/C64-FTP-Upload-tool - A small, cross-platform GUI utility to upload files from a PC to a Commodore 64 Ultimate via FTP.
• lastylegp/Quopus - Quopus Commander started life as a familiar two-panel file manager and grew teeth: a workshop for everyone who still cares about Commodore, demoscene art, and the old serial / BBS protocols. If you spend time around a real Ultimate-64, VICE, a 1541, a modem callback, or a wall of .d64 images you forgot you had - this tool was built for you.
• C64 Ultimate Viewer for Linux - A simple video & audio stream viewer designed for the new C64 Ultimate owners running Linux systems. Watch your C64 screen output on your computer with real-time streaming.
• Ultimate Remote - Remote control your Ultimate from your Android device.

• cybersorcerer/c64u - CLI for the new Commodore C64 Ultimate
• jeffsand/c64 - Command your Commodore C64 Ultimate from the terminal. npm install -g @jeffsand/c64
• carledwards/u64shell - A DOS-style TUI that mirrors a Commodore 64 Ultimate's screen live and remote-controls it — in your terminal or a browser, from one codebase. Built on u64ctl + foxpro-go.
• drericflores/c64u-cpp_remote - Remotely send and run a .PRG file on a Commodore 64 Ultimate. A Linux C++ command-line client for interacting with the Commodore 64 Ultimate over its REST API. This project is a C++ port of the original Go reference implementation and allows remote control and inspection of a C64 Ultimate from a modern Linux system.
• AllMeatball/u64-remote - Remotely send and run a .PRG file on any Ultimate device.

• chrisgleissner/c64stream - C64 Stream is an OBS Studio source plugin for streaming video and audio from Commodore 64 Ultimate devices
• gruetze-software/C64UViewer - A high-performance, lightweight remote video stream viewer for the Commodore 64 Ultimate and Ultimate-II+ ecosystem. Working on Windows and Linux.
• jusii/vlc-u64stream - VLC plugin that decodes the Ultimate 64 / Commodore 64 Ultimate raw video+audio UDP stream natively

• wiebow/d71-81writer.c64 - 1541 ultimate 2 write tool for D71 and D81 disk image files. Commodore 64 version.

Tools to prepare data on another computer before moving it over to the C64U to be used there.

• GameBase64 Game Organizer - A Python utility to organize Commodore 64 games from zip archives into a structured folder hierarchy based on metadata from VERSION.NFO files.