In TiddlyWeb a renderer is a code system that takes a tiddler as input and returns an HTML form. It is used by the HTML serializer to generate the HTML content, usually turning wikitext syntax into HTML with a wikitext renderer, such as WikklyText. This functionality was originally fully in the serializer, but it became clear with use that being able to support multiple syntaxes would be useful.

Two config items control how wikitext in tiddlers is rendered. They are wikitext_renderer and wikitext_render_map.

If the HTML form of a tiddler is requested and the type attribute on the tiddler is not set its content will be rendered by the default wikitext_renderer. In the default installation wikklytextrender is used. If the tiddlywebwiki package has not been installed, the the raw renderer is used, wrapping HTML escaped content in <pre> tags.

If the HTML form of a tiddler is requested and the type attribute begins with text/ and the type attribute is present as a key in wikitext_render_map the value in the map is used to identify the module which contains the render() method for that type.