JSON Serialize Online

Describe your JavaScript object below, build interactively, or paste code—see live JSON output, type inference, and instant validation, all in beautiful privacy.

Type or paste JavaScript object here Supports single quotes; keys without quotes; trailing commas ignored. Optional JSON Replacer Function (JavaScript) Example: To exclude "age" property, use (key, value) => (key === "age" ? undefined : value)

JSON Output (live preview)

Indentation:

Type preview:

Knowledge Base

JSON serialization converts JavaScript objects to JSON strings for storage, transmission, or configuration.
It is vital for data interchange between client/server, APIs, and saving application state.
Tools like JSON.stringify() handle nested structures, arrays, and common data types seamlessly.
Serialization ensures data can be consumed in multiple environments and programming languages.
Learn more at MDN JSON.stringify() and Json.NET Serialization Guide.

Features

Live instant preview updates as you type or modify objects.
Flexible indentation choices: compact, 2 spaces, or 4 spaces formatting.
Smart parsing supports JavaScript-like object syntax quirks.
Real-time type inference displayed for user clarity.
History navigation with arrow keys for quick access to previous objects.
Confetti animation and dark mode toggle for a delightful user experience.
100% client-side processing ensuring security and privacy of data.
One-click copy or download for easy data integration.
Wow Factor: Custom replacer support, circular reference handling, and large number precision safeguards.

FAQs

Q: What is JSON serialization?
A: It is the process of converting JavaScript objects to JSON strings, enabling data to be transmitted or stored in a standard format.

Q: How does this tool handle invalid objects?
A: The tool displays clear error messages instantly and prevents serialization until the input is corrected.

Q: Are functions or undefined values serialized?
A: No, functions and undefined are omitted as JSON cannot represent them.

Q: Is my data shared or uploaded?
A: No, all operations are performed in your browser; data never leaves your machine.

Q: Can I format the JSON output?
A: Yes, choose your indentation preferences for readability or compactness.

Q: Can I define a custom replacer function?
A: Yes, you can provide a JavaScript replacer function that filters or modifies key-value pairs during serialization.