A JSON formatter that never sees your payload.
Paste raw JSON to format, validate, or minify. Works on payloads of any size, runs entirely in your browser using the native `JSON.parse` and `JSON.stringify` APIs, and never sends your data anywhere.
0 bytesYour JSON never leaves your machine. The parser, the pretty-printer, the minifier — everything runs in this browser tab using the standard JavaScript JSON APIs. We never see what you paste, and the page makes no network calls related to your input.
A spec-compliant parser, and the obvious affordances.
The features people actually use when working with JSON — formatting, minification, error reporting — surfaced without sign-up, without ads, and without dropping your payload on a server.
Uses the browser-native `JSON.parse`, so it matches the ECMA-404 spec exactly. Trailing commas, single quotes, and unquoted keys are flagged as errors — no silent rewrites.
Pretty-print with 2 spaces (default), 4 spaces, or tabs. Switch on the fly — the output re-renders without re-parsing.
Strip every byte of optional whitespace. Useful when pasting into env vars, curl payloads, or column widths-constrained config files.
Keys, strings, numbers, booleans, and null are colored independently so scanning a nested structure is faster than reading flat text.
On parse failure, the engine surfaces the exact position and the unexpected token — the same message you would see in DevTools.
One click for either the system clipboard or a `.json` file. The download stays the formatted shape; the clipboard mirrors whatever is currently in the output pane.
Every keystroke triggers a re-parse and re-render. There is no Format button blocking your flow — and no rate limit, because nothing is being uploaded.
Use it anonymously, on as many payloads as you want. No account, no cookies, no usage counter. Inspect the network tab — there is nothing outbound to inspect.
For the work JSON usually shows up in.
When an API returns a 4xx and the body is hand-written JSON with a stray comma, the error location pin-points the offending byte. Saves the squinting-at-curl ritual.
Production services often emit single-line JSON for log shippers. Paste one in to see the actual structure — Datadog and Loki render the same way once they ingest.
Kubernetes manifests, Terraform state, OpenAPI specs — anything 200+ lines deep. Syntax highlighting makes the shape visible at a glance.
When a downstream system limits string length, the minifier strips every optional byte. Useful for stuffing JSON into CI variables or single-line YAML strings.
After decoding a JWT the payload is JSON — pretty-print it here to scan claims, expiry, scopes. Pair with the JWT decoder above for the full flow.
When integrating a third-party provider, paste an example webhook body to learn its shape before writing the type definition. The error column flags any documentation that lies.
JSON formatting, the plain answers.
Effectively no. The parser is the browser-native `JSON.parse`, which handles tens of megabytes without complaint. The bottleneck is the syntax highlighter on payloads above ~5 MB — it can take a second or two to colorize. If you hit that, use the minify button (no highlighting) or drop down to a smaller sample.
No. Every byte of the formatting pipeline runs in this browser tab. The page makes no network calls related to your input. You can verify by opening DevTools → Network and watching it while you paste and format — nothing outbound appears.
JSON has a stricter grammar than JavaScript object literals. Common rejections: trailing commas (`{"a": 1,}`), single-quoted strings (`{'a': 1}`), unquoted keys (`{a: 1}`), comments (`// …`). All of these are valid in JavaScript source code but invalid JSON. Use `JSON5` or `JSONC` parsers for those variants — this tool sticks to RFC 8259.
Not directly — JSONL is a sequence of JSON values separated by newlines, not a single JSON document. Paste one record at a time, or paste the whole file inside a `[]` array first. We are considering adding native NDJSON support; let us know if it would help your workflow.
No. The output preserves the original key order from your input. `JSON.parse` builds an object that conserves insertion order for string keys, and `JSON.stringify` walks that object in the same order. If you need alphabetical sorting, that is a separate transformation we may add later.
For pure pretty-printing and validation the two are equivalent. `jq` adds a query language for slicing, filtering, and transforming structures — far beyond what a formatter does. Use this for quick reformats and error spotting; reach for `jq` when you need real data manipulation.
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