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Stringify JSON

Turn JavaScript object literals and arrays into proper JSON strings in one step. Paste your JS data, choose the indentation, and copy the ready-to-use JSON. Free, fast and private.

Input
Output

About Stringify JSON

JavaScript and JSON look similar, but they are not the same thing. A JavaScript object literal uses unquoted keys and single quotes — {name: 'Ana'} — while JSON demands strict double-quoted syntax. Stringify JSON bridges the gap: paste your JavaScript data and get a valid JSON string back, ready for APIs, storage and configuration.

The tool evaluates JavaScript object and array literals safely, then re-emits them as proper JSON with your choice of indentation. It is ideal for converting quick test fixtures, config snippets and copy-pasted examples into the strict JSON your tools expect. All evaluation happens locally in your browser, so nothing is sent anywhere.

Features

  • JavaScript to JSON: accepts unquoted keys, single quotes and trailing commas in the input.
  • Automatic wrapping: no need to wrap objects or arrays in parentheses yourself.
  • Configurable indentation: 2-space or 4-space output to match your style.
  • Strict valid output: the result parses cleanly with JSON.parse.
  • Clear error reporting: invalid JavaScript expressions are explained instead of failing silently.
  • Copy or download: grab the JSON string or save it as a file.
  • Private by design: all evaluation happens locally in your browser.

How to Use

  1. Paste your JavaScript data — an object literal, array or scalar.
  2. Choose the indentation for the JSON output.
  3. Copy or download the resulting JSON string.

Examples

Example 1 — Test fixtures. You wrote a config as a compact JS object in a comment; convert it to JSON so a test loader can read it.

Example 2 — API contracts. Turn a mock JavaScript object into the exact JSON your API endpoint should return.

Example 3 — Migrating examples. Documentation and Stack Overflow answers often use JavaScript syntax; stringify it into strict JSON for your application.

Benefits

  • Bridge the syntax gap — from JavaScript literals to strict JSON.
  • Faster fixture creation — no manual quote fixing.
  • Consistent output — valid JSON every time.
  • Time saved — skip rewriting examples by hand.
  • Free and private — runs locally, no uploads.

Frequently Asked Questions

What is the difference between JavaScript data and JSON?
JavaScript object literals allow unquoted keys and single quotes, for example {name: 'Ana', age: 30}. JSON is a stricter text format that requires double-quoted keys and strings. This tool converts the relaxed JavaScript form into strict JSON.
Which JavaScript values are supported?
Objects, arrays, strings, numbers, booleans and null are fully supported. Functions, undefined values and circular references cannot be represented in JSON and are dropped or reported.
Do I need to wrap my object in parentheses?
No. The tool handles that for you automatically when your input starts with a curly brace or square bracket.
Is my data uploaded anywhere?
No. Everything runs locally in your browser. Your data never leaves your machine.
Is my JSON sent to a server?
No. Everything runs locally in your browser. Your data is never uploaded, stored or logged.
Can I download the result?
Yes — use the Download button below the output area, or Print / Save PDF for a printable copy.

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