NIfTI (Neuroimaging Informatics Technology Initiative) is a specialized file format designed to provide a coordinated approach to the storage and exchange of neuroimaging data. It was developed as a successor to the older ANALYZE 7.5 format to address specific deficiencies, such as the lack of standardized orientation information and the cumbersome separation of header and image data. The format primarily uses the .nii extension, which encapsulates both the metadata (header) and the raw voxel data in a single file, though it can also exist as a pair of .hdr and .img files. NIfTI files are widely used in the medical research community for storing MRI (Magnetic Resonance Imaging) and fMRI (functional MRI) scans. One of its key features is the inclusion of affine transformations in the header, which allows software to map voxel coordinates to real-world spatial coordinates, such as MNI or Talairach space. This ensures that brain images are correctly oriented and aligned across different analysis platforms. The format supports various data types, including integers and floating-point numbers, and can handle multidimensional data beyond three spatial dimensions, such as time series or diffusion gradients. Because of its simplicity and robustness, it has become the de facto standard for neuroimaging research and data sharing.