[1][2] Netstrings store the byte length of the data that follows, making it easier to unambiguously pass text and byte data between programs that could be sensitive to values that could be interpreted as delimiters or terminators (such as a null character).
The format consists of the string's length written using ASCII digits, followed by a colon, the byte data, and a comma.
The comma makes it slightly simpler for humans to read netstrings that are used as adjacent records, and provides weak verification of correct parsing.
For example, see its use in the Simple Common Gateway Interface (SCGI) and the Quick Mail Queuing Protocol (QMQP) .
Netstrings avoid complications that arise in trying to embed arbitrary data in delimited formats.