Leaflet

Leaflet may refer to a small printed informational sheet distributed for advertising or instructions. It also denotes Leaflet.js, a widely used open-source JavaScript library for interactive maps in web pages. Leaflet.js provides a lightweight, dependency-free API for creating map interfaces.

The project was created by Vladimir Agafonkin in the early 2010s and has grown through contributions from a large community of developers. The library emphasizes simplicity and performance, with a small core size and a modular approach via plugins. It is designed to run in modern desktop and mobile browsers and supports touch interactions.

Key features include tile layers for basemaps, markers and popups, vector overlays, layers and controls, events, and a flexible rendering system. Leaflet can work with tile providers such as OpenStreetMap and others, and supports custom overlays, heatmaps, and more through plugins. The API focuses on an intuitive, consistent experience across devices, and it can be extended with numerous plugins from the ecosystem.

Under the BSD-2-Clause license, Leaflet is maintained by a community of volunteers and is hosted on repositories such as GitHub. It has become one of the standard choices for building web-based maps due to its balance of simplicity, performance, and extensibility.