JSZip Lets Developers Parse and Create ZIP Files Entirely in the Browser

JSZip is a JavaScript library that enables developers to read and create ZIP archives directly in the browser, eliminating the need for server-side processing. This approach is particularly useful when handling sensitive documents such as legal filings, medical records, or financial data, as the files never leave the user's device. The library supports extracting text, images, and other file types from ZIP archives, as well as generating new ZIP files with DEFLATE compression. For large files exceeding 10MB, JSZip provides a progress callback to monitor processing, with benchmarks showing parse times ranging from around 5ms for 50KB files to roughly 900ms for 50MB files. The technique was applied in a real-world tool called udf2md, which converts Turkish court documents to Markdown in the browser with no backend, aiding compliance with GDPR and Turkey's KVKK data protection regulations.