Question 1

What does Format / Decode do?

Accepted Answer

Format / Decode is the main action. It pretty-prints any JSON-like input with 2-space indentation and also handles common problems automatically: unquoted keys, single-quoted strings, trailing commas, JavaScript-style comments, and double-encoded strings (a JSON string wrapped in an extra layer of JSON.stringify). If the input cannot be parsed at all, the tool still shows a best-effort formatted view alongside the exact parse error.

Question 2

What does Encode do and when would I use it?

Accepted Answer

Encode takes a valid JSON document and produces a double-encoded string — the equivalent of calling JSON.stringify twice. The result is a JSON string value whose content is itself a JSON document. This is useful when you need to embed a JSON payload inside another JSON field, for example in some API request bodies or configuration files that store serialised JSON as a string property.

Question 3

Is my JSON data uploaded to a server when I use this tool?

Accepted Answer

No. Every operation — Format / Decode, Encode, and local save — runs entirely inside your browser. Nothing you paste is ever transmitted to any server, stored remotely, or logged. The Save feature writes only to your own browser's localStorage.

Question 4

What is the API Name / Title field for?

Accepted Answer

The API Name is the key used to save and retrieve a JSON snippet from your browser's localStorage. Enter a descriptive name (e.g. "User profile response" or "Auth token payload"), then click Save. Later, click List to see all saved snippets, load one back into the editor, or delete it. Saved data never leaves your device.

Question 5

Why does Format / Decode still show an error but also show output?

Accepted Answer

When the input cannot be fully parsed, the tool falls back to a character-by-character loose formatter that adds indentation without actually understanding the structure. This gives you a readable view that makes it easier to spot the problem. Fix the highlighted error (the message shows the line and column or character position) and run Format / Decode again for a fully valid result.

JSON Encoder & Decoder — Format, Validate & Escape

How to Use

Frequently Asked Questions

Related Tools