This document specifies the basic brain–computer interface (BCI) data format including the definition of basic data elements, technology-specific information and metadata, design of an extensible and modular data structure, specification of metadata and annotation information, and the development of a standardized data format and naming convention for BCI data. This document is applicable to non-invasive BCI technologies, such as electroencephalography (EEG), magnetoencephalography (MEG), functional near-infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI), and provides a comprehensive approach to BCI metadata formats in the product development environment. It takes into consideration various applications, ranging from neurological rehabilitation to human–computer interaction.