The Compression Streams API is a modern browser API that provides native, hardware-accelerated compression and decompression of data streams using standard formats like Gzip and Deflate. It's part of the browser's built-in capabilities and doesn't require any external libraries, making it fast and efficient for processing data directly in the browser.

The API supports three formats: Gzip (RFC 1952, the most common format used in .gz files and HTTP compression), Deflate (RFC 1950, deflate wrapped in a zlib header), and Deflate-Raw (RFC 1951, pure deflate without any headers). Gzip is the most widely compatible and recommended for general use.

The API is supported in Chrome 80+, Edge 80+, and Opera 67+. As of 2024, Firefox and Safari have limited or no support. You can check the current support status using the badge at the top of this tool. For unsupported browsers, consider using a polyfill or a JavaScript library like pako.

Gzip wraps deflate-compressed data with a gzip header (containing metadata like filename and timestamp) and a CRC32 checksum. Deflate (zlib) wraps the deflate data with a smaller zlib header and an Adler-32 checksum. Deflate-Raw is the pure deflate compressed stream with no headers or checksums — it's the core compression algorithm without any wrapper. Choose Gzip for maximum compatibility.

This is normal for very small inputs. Compression formats add headers and metadata overhead (typically 20-30 bytes for gzip). For inputs smaller than a few hundred bytes, the overhead can exceed the compression savings, resulting in a larger output. Compression becomes effective for inputs larger than ~500 bytes, especially with repetitive patterns like JSON, HTML, or CSS.

Yes! The Compression Streams API works with any binary data. You can upload images, documents, or any file type for compression. However, keep in mind that formats like JPEG, PNG, MP4, and ZIP are already compressed — re-compressing them usually yields little to no size reduction and may even increase the file size slightly.

The underlying algorithm is identical. Server-side gzip (used in Nginx, Apache, etc.) and the browser's Compression Streams API both use the DEFLATE algorithm as defined in RFC 1951. The difference is where the compression happens: server-side compresses before sending data over the network, while this API compresses data client-side, which is useful for preparing data before upload or for offline/PWA applications.

Absolutely. The Gzip output is fully compatible with command-line tools like gzip, gunzip, zcat, and any software that handles .gz files. The Deflate output is compatible with zlib-based tools. You can download the compressed files and decompress them on any system using standard utilities.