ADVERT

JSON.stringify Playground

Interactively explore JSON.stringify options. Try replacer arrays or functions, adjust indentation, and inspect replacer call traces.

Input JSON

Replacer modeReplacer function body

Indentation: 2

Sort keys before stringifyTrace replacer calls

Stringify output

Custom replacer function

JSON.stringify(value, replacer, 2);

{
  "email": "ada@example.com",
  "id": 42,
  "metrics": {
    "conversion": 0.48,
    "createdAt": "1843-12-10T00:00:00.000Z",
    "visits": 1234
  },
  "name": "Ada Lovelace",
  "roles": [
    "admin",
    "editor"
  ]
}

Characters222

Lines14

Replacer trace

KeyIncoming valueReturned value

(root){"email":"[email protected]","id":42,"metrics":{"conversion":0.4821,"createdAt":"1843-12-10T00:00:00.000Z","visits":1234},"name":"Ada Lovelace","password":"supers3cret","roles":["admin","editor"]}{"email":"[email protected]","id":42,"metrics":{"conversion":0.4821,"createdAt":"1843-12-10T00:00:00.000Z","visits":1234},"name":"Ada Lovelace","password":"supers3cret","roles":["admin","editor"]}

email[email protected][email protected]

id4242

metrics{"conversion":0.4821,"createdAt":"1843-12-10T00:00:00.000Z","visits":1234}{"conversion":0.4821,"createdAt":"1843-12-10T00:00:00.000Z","visits":1234}

conversion0.48210.48

createdAt1843-12-10T00:00:00.000Z1843-12-10T00:00:00.000Z

visits12341234

nameAda LovelaceAda Lovelace

passwordsupers3cretundefined

roles["admin","editor"]["admin","editor"]

0adminadmin

1editoreditor

How to use this tool

Paste JSON input and choose replacer mode (none, keys, or function).
Adjust indentation and optional key sorting to simulate production output.
Inspect output plus replacer trace details, then copy serialized JSON.

Learning and debugging use cases

Understand how replacers transform or omit fields during serialization.
Prototype API payload sanitization before shipping application code.
Validate whitespace and structure for logs, snapshots, or fixtures.

Serializer behavior notes

Returning undefined can omit keys or whole payloads depending on position.
Function replacers run for root and nested keys in traversal order.
Trace output is capped to avoid UI slowdown on large objects.

FAQ

Can I test whitelist array replacers?: Yes. Use key whitelist mode and provide comma-separated property names.
Why is output blank sometimes?: If the root value is omitted by replacer logic, JSON.stringify returns undefined.
Is code executed remotely?: No. Parsing and replacer execution happen locally in your browser.

ADVERT

Stringify output

Replacer trace

How to use this tool

Learning and debugging use cases

Serializer behavior notes

FAQ

More like this

Stringify output

Replacer trace