Overview
donjon is a legendary, minimalist suite of web-based procedural generators that has served as the "Swiss Army Knife" for Game Masters since its first dungeon generator went live in 1999. Created and maintained by a developer known as drow, the site eschews modern flashy graphics and subscriptions in favor of raw utility and speed. In late 2025 and 2026, the site saw a significant "5.5 Refactor," adding full support for the 2024 D&D Core Rules, including new treasure tables, encounter calculators, and Bastion event generators.
Description
donjon is the ultimate tool for the "Zero-Prep" GM. It is a collection of text and image-based algorithms that can generate everything from a single NPC to an entire star system in less than a second. While newer tools focus on 3D visuals, donjon remains a favorite because it is incredibly lightweight; it loads instantly on any device and provides high-density information without any clutter. It is the "source code" of many GMs' campaigns, providing the mechanical backbone for loot, encounters, and world-building data.
System Overview & Key Features
Random Dungeon Generator
The crown jewel of the site. It creates fully mapped-out dungeons with "old-school" aesthetics. You can specify the level, layout, and "dungeon motif" (like Sunken Temple or Abyssal Rift), and it will populate the map with traps, secret doors, wandering monsters, and room descriptions automatically.
D&D 5.5 / 2024 Core Support
New for 2026, the site features a dedicated "5.5" section. This includes an updated Encounter Size Calculator that accounts for the 2024 power scaling, as well as a Magic Shop Generator that utilizes the new pricing and item rarity structures introduced in the latest D&D revision.
Fractal World Generator
This tool uses a recursive algorithm to generate entire world maps with realistic coastlines, islands, and tectonic-like features. GMs can adjust the "Ice Limit," "Water Percentage," and "Scale" to create a unique continent or a planet-wide archipelago in seconds.
Sci-Fi and Weird Fiction Suites
Beyond fantasy, donjon is the premier source for Star Wars (d6/d20) and Traveller star system generators. It also features a Weird Fiction section for Call of Cthulhu players, generating eldritch tomes, blasphemous rituals, and sanity-testing NPCs.
The "Endless Oubliette"
For GMs running "Megadungeons," this tool uses Dyson Logos-style geomorphs to generate an infinitely expanding dungeon. As players move through the map, the GM can keep generating new sections, ensuring the dungeon literally never ends.
HTML and TSV Exports
Almost every generator on the site allows you to export results as a raw text file or a portable HTML page. This is essential for GMs who want to copy-paste generated NPCs directly into Discord or import loot tables into Foundry VTT or Obsidian.
Additional links
donjon.bin.sh 
https://donjon.bin.sh - Official donjon website and site index