Overview
The Medieval Fantasy City Generator (MFCG) is a highly influential, browser based procedural tool created by the developer watabou. Since its debut in 2017, it has become the gold standard for "instant" urban cartography, capable of generating complex, aesthetic city layouts in a single click. In late 2025 and early 2026, the tool received significant updates to its District View and Building Placement algorithms, allowing for more organic street flow and higher density urban "slums" that better reflect historical medieval layouts.
Description
The Medieval Fantasy City Generator is a "toy" in the best sense of the word—a lightweight, highly customizable application that prioritizes "cool looking" maps over strict geographical simulation. It uses Voronoi diagrams to partition space into districts, then fills them with procedurally generated buildings, walls, and landmarks. Because it runs entirely in HTML5, it requires no installation and is a favorite for GMs who need to generate a "capital city" or "coastal port" on the fly during a live session.
System Overview & Key Features
One Click Generation
Pressing a single key (Enter) generates a completely new city with unique geography. The tool automatically decides where the castle, the temple, and the market square go, providing an instant foundation for a Game Master to build their narrative upon.
Procedural District Mapping
The 2026 version features an improved "Alleys and Blocks" view. Cities are divided into logical districts—like the Craftsmans Quarter or the Shanty Town—each with its own architectural density and procedurally generated name that can be edited by the user.
Dynamic Warp Tool
GMs can manually reshape the city by "warping" its boundaries. If you need a city that is long and thin to fit a specific riverbank, or a circular fortress atop a hill, the warp tool allows you to push and pull the city's footprint while the buildings rearrange themselves in real time.
3D City Viewer Integration
By exporting a city as a JSON file, users can open their map in the companion City Viewer app. This transforms the 2D layout into a fully navigable 3D environment, perfect for showing players the "skyline" of the city they are about to enter.
SVG and JSON Export
Maps can be exported as high quality SVG files, allowing them to be opened in programs like Illustrator or Inkscape for further artistic customization. The JSON export ensures full compatibility with other "Procgen Arcana" tools and major VTTs like Foundry.
Azgaar's Integration
The generator is natively linked to Azgaar's Fantasy Map Generator. When a user clicks on a city in a world map, it can automatically trigger the Medieval Fantasy City Generator to build that specific town, creating a seamless "World to Street" experience.
Additional links
watabou.itch.io/medieval-fantasy-city-generator 
https://watabou.itch.io/medieval-fantasy-city-generator - Official application page
watabou.github.io https://watabou.github.io - The full "Procgen Arcana" suite of generators
patreon.com/watabou https://patreon.com/watabou - Official Patreon for supporting the developer