bytestream

A bytestream is a sequence of bytes that can be read or written sequentially. It provides a low-level channel of data where the payload is treated as raw bytes, not as characters or structured messages. Bytestreams are used for binary data, file I/O, network communication, and inter-process communication where exact byte values must be preserved.

In contrast with character streams, bytestreams do not perform character encoding or decoding. Read operations return raw bytes up to a requested length and may return fewer bytes than requested, with an end-of-stream indication. Write operations append bytes to the stream. Many languages provide standard abstractions for bytestreams, such as Java's InputStream/OutputStream, Python's files opened in binary mode, or the io.BytesIO class, and C/C++ FILE in binary mode or sockets.

In networking, a bytestream often implies a stream-oriented transport such as TCP, in which data is delivered as a continuous sequence of bytes without explicit message boundaries. Protocols built on top of such streams add framing to delineate messages. Bytestreams must be buffered and interpreted by application logic to recover discrete records.

When exchanging data across platforms, attention to endianness and integer sizes is important, since the same byte sequence may be interpreted differently by different architectures if not defined.

See also: binary data, stream, endianness, input/output, I/O stream.