jdBasic - A Persistent Experimental BASIC Environment

jdBasic is a modern BASIC interpreter built around a custom bytecode virtual machine with APL-style array programming, hot-reloadable code, a persistent REPL workspace, and first-class graphics, GUI, audio, networking, AI, and Godot-engine integration.

It combines the immediacy of classic BASIC with powerful built-in capabilities and a "stay in the session" philosophy - no constant restarts, no rebuild loops, just think and run.

Reduce friction between thinking and running code.

<p align="center"> <img src="doc/img/prisma.png" width="30%" alt="PRISMA, a match-3 game written in pure jdBasic"/> <img src="doc/img/godot_rpg.jpg" width="38%" alt="A 3D RPG in Godot whose NPC dialogue brain is a local LLM, scripted entirely in jdBasic"/> <img src="doc/img/vscode_forms_designer.png" width="30%" alt="The VS Code visual form designer editing a .jdform layout"/> </p> <p align="center"><em>A match-3 game, a Godot RPG whose NPCs think with a local LLM, and the VS Code form designer - all scripted in jdBasic.</em></p>

🎥 Train jdBasic is on YouTube - 14 video lessons covering everything from PRINT to native compilation, all auto-generated and voiced by jdBasic itself. Watch the playlist →

You can:

• explore ideas in a powerful interactive REPL
• save and restore entire sessions with SAVEWS / LOADWS
• write vectorized data pipelines using APL-inspired array operators
• prototype graphics, games, and tools with SDL3 + Dear ImGui
• embed in Godot 4 and script whole 3D games, tools, and visualizers in pure BASIC
• talk to local LLMs (llama.cpp) and run ONNX models inline
• pair-program with an AI agent: the built-in MCP server exposes a persistent VM that Claude Code, Cursor & Co. can run, inspect, and live-patch without restarting your program
• build automation tools, REST clients, and serial-device controllers
• extend the language with native modules

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Try jdBasic in your browser

jdbasic.org/live - no installation required.

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Watch the lessons

The Train jdBasic YouTube series walks through the language from "Hello, World" to native compilation - 14 episodes, 5–10 minutes each, with auto-generated chapters and code-on-screen as it happens.

▶️ Full playlist on YouTube

#	Lesson	Topic
01	Hello jdBasic	PRINT, DIM, basic types
02	If and For	IF/ELSE, FOR/NEXT, FizzBuzz
03	Arrays	Vector ops, broadcasting, reductions
04	Strings	Slice, search, SPLIT
05	Functions and SUBs	FUNC, SUB, recursion
06	Maps	Key-value data
07	INPUT and DO Loops	User-driven programs
08	File I/O	TXTWRITER, TXTREADER$
09	Graphics	SCREEN, shapes, colours
10	Modules	EXPORT, IMPORT, code reuse
11	[REPL Workflow]