Yes. When retrieving a single tiddler or multiple tiddlers you can cause the server to include a render attribute with a value which is the rendered HTML of the tiddler. You do this by adding a 'render=1' query parameter to the request. See also How can I GET many tiddlers at once? render and fat, since version 1.2.57 are independent of one another.

Some examples:

• http://tiddlyweb.tiddlyspace.com/bags/tiddlyweb_public/tiddlers/renderer.json
• http://tiddlyweb.tiddlyspace.com/bags/tiddlyweb_public/tiddlers/renderer.json?render=1
• http://tiddlyweb.tiddlyspace.com/bags/tiddlyweb_public/tiddlers/renderer.json?fat=0
• http://tiddlyweb.tiddlyspace.com/bags/tiddlyweb_public/tiddlers/renderer.json?fat=0&render=1