file-type is a utility for detecting file types by examining file contents rather than relying on extensions or MIME type declarations.
The tool solves the problem of accurately identifying what a file actually contains, which matters when you cannot trust file extensions or when you need to validate uploads. It works by reading the beginning of a file or data buffer and matching against known file signatures, also called magic numbers. This approach detects the true format regardless of what name or extension the file carries. The tool supports detection from files on disk, readable streams, and raw data buffers, making it flexible for different input sources.
Developers should choose this tool when building file upload validators, content analysis systems, or any feature where knowing the actual file type is critical for security or functionality. It suits projects that need reliable file type identification without external dependencies or system calls. The tool works with Node.js and browser environments where Uint8Array is available.
The project maintains a focused scope with regular updates to support newly discovered file formats and to address edge cases in detection logic. Maintenance activity shows consistent attention to keeping the format signatures current and the codebase aligned with evolving JavaScript standards. The tool receives ongoing refinement to handle both common and uncommon file types accurately.
