Compress or decompress raw DEFLATE streams (no header, no checksum) up to 2 GiB in your browser, with a level from 0 to 9.
Runs in your browser — your input is processed on this device and never uploaded.
Pasted text up to 100 MiB, read as UTF-8, or a file up to 2 GiB.
Results appear here.
Raw DEFLATE is the compressed bytes themselves. There is no header and no checksum. Gzip and zlib both wrap this stream, and a zip entry often stores it directly.
This tool compresses bytes into a raw DEFLATE stream, or decompresses one back to the original bytes.
A container that already records the length and a checksum does not need another one. Zip entries, and the compressed data inside PNG, keep the wrapper outside the DEFLATE bytes so it is not counted twice.
Without that wrapper, the bytes do not identify themselves. This tool trusts the action you pick. It does not inspect the input and decide which format it is.
Gzip and zlib are the same compressed bytes with a header and a checksum. This page will not open those. A .br (Brotli) or .zst (Zstandard) file is a different algorithm and will not open here either.
The gzip command on your computer can still inflate a raw stream with gzip -d only when the stream is actually gzip. For a raw stream, tools such as Python's zlib with a negative window, or openssl zlib, are the usual choice for files larger than 2 GiB.
Phil Katz designed DEFLATE for PKZIP. The format of the raw stream is RFC 1951. The specification writes the name in capitals.
A damaged raw stream can expand into the wrong bytes, because nothing in the stream says it is intact. Gzip and zlib fail when their checksum does not match. Raw DEFLATE cannot do that check.
There is no standard file suffix. This tool uses .deflate so the download is easy to tell apart from a gzip or zlib file.
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