Claude Code doesn’t use a traditional file upload mechanism since it operates directly within your terminal environment and has access to your entire project directory structure. Instead, it can read and process virtually any file type that exists within your project folder, making it much more flexible than web-based interfaces with specific upload restrictions. For source code, Claude Code supports all common programming languages including Python, JavaScript, TypeScript, Java, C++, C#, Ruby, Go, Rust, PHP, and many others, along with configuration files like JSON, YAML, TOML, XML, and environment files. It can also work with markup languages like HTML, CSS, Markdown, and documentation formats, making it suitable for full-stack development projects that involve multiple technologies and file types.
For data analysis and processing tasks, Claude Code can handle structured data files including CSV, Excel spreadsheets (XLSX), JSON, TSV, and other tabular data formats. It can read and analyze database files, log files, and various text-based data formats. Claude Code also has image analysis capabilities, allowing it to process and interpret visual files like JPEG, PNG, GIF, and WebP images, which is particularly useful for analyzing charts, diagrams, screenshots, or design mockups that are part of your project. Additionally, it can work with binary files, compressed archives, and proprietary file formats by using appropriate tools and libraries available in your development environment.
The file processing capabilities extend beyond just reading to include transformation and generation tasks. Claude Code can convert between different file formats, extract data from complex file structures, generate new files based on existing ones, and even work with version control files to understand project history and changes. Unlike web-based interfaces that typically have file size limits (usually around 10-30MB), Claude Code can process files of any size that your system can handle, making it suitable for large datasets, extensive codebases, or comprehensive documentation projects. The key limitation is not file type support but rather token usage and processing time, as larger files consume more computational resources and may impact response speed and cost efficiency.