JSON Formatter & Validator
100% private: your JSON is parsed and formatted entirely on your device. Nothing is sent to a server, logged, or stored — safe for config files, API responses, and data with sensitive values.
JSON is the language APIs, config files, and web apps speak, but it's unforgiving: one missing comma, a trailing comma, a stray quote, or a single-quoted string and the whole thing fails to parse. When JSON arrives minified — squeezed onto one enormous line — it becomes almost impossible to read or debug by eye. This formatter fixes both problems. Beautify re-indents the structure so you can actually see the nesting; minify does the reverse when you need the smallest possible payload; and validate runs the exact same parser your browser and most servers use, so if it passes here, it's genuinely well-formed JSON.
The real time-saver is the error reporting. Instead of a vague "unexpected token", the tool converts the parser's character position into a human line-and-column reference and shows you the snippet around the break, so you go straight to the problem instead of hunting for it. It handles deeply nested objects, large arrays, Unicode, and escaped characters, and it can sort object keys alphabetically to make two versions of the same data easy to compare.
Because everything happens inside your browser using the built-in JSON engine, nothing you paste ever leaves your device. That matters: JSON often carries access tokens, personal records, internal IDs, and other data you should never hand to a random website. Many online formatters quietly send your text to their servers — this one physically cannot, because there is no server call in the code. Paste production data, API keys, or customer records with confidence; it all stays on your machine and is gone the moment you close the tab.
No. All parsing, formatting, minifying, and validation happen in your browser using JavaScript's built-in JSON engine. There is no network request in this tool — you can even disconnect from the internet and it will still work. Your data never leaves your device, which makes it safe for JSON containing tokens, credentials, or personal information.
It runs your text through the same strict JSON parser browsers and servers use. If it parses, it's valid JSON — correct quoting, commas, brackets, and value types. If it fails, you get the exact line and column of the first error and the character that caused it, so you can fix it immediately. Note that valid JSON uses double quotes, no trailing commas, and no comments.
The most common culprits are single quotes instead of double quotes, a trailing comma after the last item in an object or array, comments (which standard JSON doesn't allow), unquoted keys, or a value like undefined or NaN. The error message points to the first spot the parser choked on — fix that and re-run; sometimes one fix reveals the next.
Yes, within reason. Because it runs in your browser, performance depends on your device's memory, but it comfortably handles typical API responses and config files up to several megabytes. Extremely large files (tens of megabytes) may format slowly or strain the browser tab, since the whole structure is held in memory at once.
Beautify adds indentation and line breaks to make JSON readable for humans — ideal for debugging and inspecting data. Minify removes all unnecessary whitespace to make the JSON as small as possible — ideal for sending over a network or embedding, where every byte counts. Both produce the exact same data; only the formatting differs.