dhtmlxScheduler is a web-based event calendar which provides simple in-browser scheduling solution. With smooth Ajax-enabled interface dhtmlxScheduler allows users to add, modify or delete events without refreshing the web page. Intuitive drag-n-drop behavior gives the possibility to change events date and start/end time by simply dragging the event boxes. The calendar events can be displayed in Day/Week/Month views. dhtmlxScheduler is very lightweight (about 19KB gzipped), cross-browser and highly customizable. Each aspect of the calendar interface can be configured through JavaScript API. Developers can easily add/update events, change date format, time scale or calendar language. dhtmlxScheduler is distributed under GNU GPL and commercial licenses.