JSON.stringify, JSON.parse, and Escaping

JSON.stringify converts a JavaScript value to JSON text. JSON.parse reads JSON text and returns a JavaScript value. Escaping is the narrower task of representing characters inside a JSON string literal.

One object, three representations

Suppose a program has the value { name: 'Alex' }. This is JavaScript object notation, not JSON text. JSON.stringify({ name: 'Alex' }) returns the string of characters {"name":"Alex"}. Those characters form a valid JSON document representing an object.

If you need to place that entire document inside a JSON string, the string literal is "{\"name\":\"Alex\"}". The outer quotes and backslashes belong to the encoded string, not to the object document.

Input	Operation	Result
hello	Escape text	"hello"
"hello"	Unescape JSON string	hello
{"name":"Alex"}	Stringify JSON document	"{\"name\":\"Alex\"}"
"{\"name\":\"Alex\"}"	Unstringify document	{"name":"Alex"}

Try these modes in the JSON escape and unescape tool. Its stringify document mode validates the source as JSON, then wraps its exact text as a string. In JavaScript, JSON.stringify(JSON.parse(text)) may normalize formatting and number representation instead.

Parsing failures

JSON.parse('{name:"Alex"}') throws because the property name is not in double quotes. JSON.parse('"hello"') returns the plain string hello; JSON.parse('hello') throws because bare hello is not JSON. The validator explains malformed JSON with a location.

Never use eval() to decode JSON. It executes JavaScript and accepts syntax that strict JSON does not. For the JSON grammar and escaping rules, see RFC 8259.