JSON Stringify Online.

JSON stringify online - free and private

A JSON stringify online tool converts valid JSON into an escaped string literal. That is useful when you need to paste JSON into JavaScript, app config, logs, database text fields, documentation, test fixtures, or any place where quotes and newlines must be escaped. This tool validates the JSON first, then stringifies it safely in your browser.

How to stringify JSON in three steps

1. Paste valid JSON into the input box or load the sample.
2. Choose quote style - double quotes, single quotes, or backticks.
3. Stringify and copy the escaped string literal or download it as text.

Escape JSON for embedding in code or DB fields

Stringified JSON escapes the characters that break string literals: quotes, backslashes, newlines, tabs, carriage returns, and control characters. Use double-quoted output for strict JSON string values, single-quoted output for many code and text-field workflows, and backtick output when a JavaScript template literal is more convenient.

Unstringify JSON on the same page

Need to reverse the process? Switch to Unstringify / parse mode and paste a quoted escaped string such as "{\"name\":\"Ada\"}". The tool decodes the string body, validates the decoded JSON, and returns formatted or minified JSON.

The three arguments to JSON.stringify

JSON.stringify(value, replacer, space)

The first is your data. The third is the one everyone actually wants and half of people never learn — it is the indent:

JSON.stringify(data)             // minified
JSON.stringify(data, null, 2)    // pretty-printed, 2-space
JSON.stringify(data, null, "	") // pretty-printed, tabs

The second is a replacer — pass an array of keys to keep only those fields, or a function to transform values as they serialise. It is the tidiest way to strip a password out of an object before logging it.

The silent data loss nobody warns you about

Several JavaScript values have no JSON equivalent, and JSON.stringify discards them without a word:

JSON.stringify({
  a: undefined,        // key vanishes entirely
  b: () => {},         // functions vanish
  c: Symbol("x"),      // symbols vanish
  d: NaN,              // becomes null
  e: Infinity,         // becomes null
  f: new Date(),       // becomes an ISO string
});
// {"d":null,"e":null,"f":"2026-07-12T10:00:00.000Z"}

Keys a, b, and c are simply gone. Inside an array they behave differently again — undefined becomes null rather than disappearing, which quietly changes your data instead of shrinking it.

And note f: a Date serialises to a string and does not come back as a Date when you parse it. Round-tripping through stringify and parse gives you equivalent data, not identical data.

Circular references throw

const a = {};
a.self = a;
JSON.stringify(a);   // TypeError: Converting circular structure to JSON

JSON is a tree and cannot express a cycle, so there is no way around this except to break the cycle first — either delete the offending reference, or pass a replacer that tracks objects it has already seen and drops repeats.

JSON stringify vs JSON escape

JSON Escape is best when you have raw text and want to make it safe inside a JSON string. JSON Stringify is best when you already have full JSON and want to serialize the whole object, array, string, number, boolean, or null as an escaped string literal. You can also use JSON Formatter or JSON Validator before embedding. Learn more in how to stringify JSON online.