Tiddlywiki ni wiki ya kibinafsi na daftari isiyo ya mstari wa kuandaa na kushiriki habari ngumu. Ni programu ya wazi ya ukurasa mmoja wa Wiki katika mfumo wa faili moja ya HTML ambayo inajumuisha CSS, JavaScript, na yaliyomo. Imeundwa kuwa rahisi kubinafsisha na kuunda tena kulingana na matumizi. Inawezesha utumiaji wa yaliyomo tena kwa kuigawanya vipande vidogo vinavyoitwa Tiddlers.

TiddlyWiki is designed for customization and to be shaped according to users’ specific needs, perhaps comparable to a high-end programming language. As such, it can be shaped into a wide and arbitrary range of special applications. Examples include niche note taking applications, to-do lists, presentations, collections, authoring tools, personal databases, recipe collections, etc.

Although there are many TiddlyWiki documents on the Web, the majority of TiddlyWikis reside on personal computers or in the cloud, or are exchanged over email, in a manner similar to word processing documents and spreadsheets. As a single HTML file, or saved as an HTA file in Microsoft Windows (allowing corporate IE lockdown to be bypassed), TiddlyWiki can be useful in corporate environments where red tape or IT resources might prevent the use of a wiki that requires a more complicated installation.