Deflate compress

It is the same deflate algorithm with no wrapper at all. gzip adds a header with a CRC-32, zlib adds a small header with an Adler-32, and raw deflate adds neither, so it is the smallest of the three and carries no integrity check. Use it when another program expects raw deflate, which is common inside file formats and protocols.

Your file name with .deflate appended, keeping the original extension, so payload.bin becomes payload.bin.deflate. Deflate decompress strips that suffix back off. The extension is a convention used here for the round trip, not a standard. Any program expecting raw deflate will read the contents whatever the file is called.

No. The tool has no options and uses the fflate default every run, so the same input always produces the same bytes. If you need to tune the level or the strategy, use a library or a desktop tool that exposes them.

No. A raw deflate stream is not an archive and has no header for a tool to recognise, so a desktop archiver will refuse it. It is meant to be fed back to something that expects raw deflate, or to Deflate decompress here.

No. Deflate compresses one stream of bytes, with no notion of file names or directories. Bundle first with Create tar or Create ZIP if you need structure. For a single file the result is the compressed stream alone, with no name, no timestamp and no checksum stored beside it.

No. It is compressed in a Web Worker in your own tab with nothing sent to a server. The input and the output are held in memory together, so the practical size limit is your device. There are no accounts and no network calls, and the page keeps working once you switch your connection off.