Octra is an open-source editor for web-based orthographic transcription. It runs in a web browser on any platform, and operates in an online and a local mode. In the local mode, files are opened via drag & drop on the browser window, in the on line mode the transcriber logs in and selects the transcription project; the next file to transcribe is opened immediately. Octra features three different viewers: dictaphone, linear and 2D, and it may access external web services, e. g. for ASR or time-aligning the transcript and the signal. It supports various common file formats for interoperability, for import and export. In Octra, a transcriber places boundaries in the signal and then transcribes these transcription units. The length of the tran scription units is determined by the personal preferences of the transcriber, and may vary with the type of recordings.