ニコ動履歴 is a free Chrome extension developed by mochixp. It allows users to keep track of their viewing history on NicoNico Douga, a popular Japanese video-sharing website. With this extension, users can record up to 50,000 history entries and have the ability to individually delete entries. The extension also provides features such as sorting the history, searching for keywords, searching for tags, and searching for tags that include specific keywords.

Please note that the current version of the extension may contain a number of bugs due to significant internal changes being made. If you encounter any bugs or have any feature requests, the developer can be contacted through email at or via Twitter at mochixp.