ydb/library/cpp/json/writer/README.md

JSON writer with no external dependencies, producing output where HTML special characters are always escaped.

Use it like this:

#include <library/cpp/json/writer/json.h>
...

NJsonWriter::TBuf json;
json.BeginList()
    .WriteString("<script>")
    .EndList();
Cout << json.Str(); // output: ["\u003Cscript\u003E"]

For compatibility with legacy formats where object keys are not quoted, use CompatWriteKeyWithoutQuotes:

NJsonWriter::TBuf json;
json.BeginObject()
    .CompatWriteKeyWithoutQuotes("r").WriteInt(1)
    .CompatWriteKeyWithoutQuotes("n").WriteInt(0)
.EndObject();
Cout << json.Str(); // output: {r:1,n:0}