JSON Tools
19 free tools · 100% client-side
Professional JSON tools that run entirely in your browser: format, validate, minify, view, sort, and compare JSON with a VS Code-style editor.
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Most-used JSON Tools
JSON Formatter
Format, beautify, and validate JSON instantly in a professional VS Code-style editor — free, fast, and 100% private.
JSON Parser
Run a real JSON parse in your browser — see exactly what your application will see, or exactly where it will fail.
JSON Validator
Strict RFC 8259 validation with the exact line and column of every error — plus one-click repair for broken JSON.
All 19 JSON Tools
JSON Formatter
Format, beautify, and validate JSON instantly in a professional VS Code-style editor — free, fast, and 100% private.
JSON Validator
Strict RFC 8259 validation with the exact line and column of every error — plus one-click repair for broken JSON.
JSON Editor
A full VS Code-style editing experience for JSON — highlighting, error squiggles, undo/redo, search, and formatting in one place.
JSON Pretty Print
Turn dense single-line JSON into beautifully indented, readable output — your choice of indentation, with optional alphabetical key sorting.
JSON Viewer
Explore any JSON document in an interactive, collapsible tree — keys, types, and counts at a glance, with code view one click away.
JSON Parser
Run a real JSON parse in your browser — see exactly what your application will see, or exactly where it will fail.
JSON Minifier
Compress JSON to its smallest valid form by stripping every unnecessary character — with full validation built in.
JSON Stringify Online
The exact behavior of JavaScript's JSON.stringify() — compact by default, the space argument, and what the serializer silently drops — plus a mode that reverses it.
JSON to One Line
Strip every line break and indent from your JSON to get a clean single-line version — perfect for logs, env vars, and curl.
JSON Compare
Side-by-side JSON diffing with VS Code's engine — highlighted changes, editable panes, and key-order-insensitive comparison.
JSON Sorter
Recursively sort every object's keys A→Z — arrays keep their order — for stable diffs, clean reviews, and canonical configs.
JSON5 Formatter
Beautify JSON5 the way it's meant to be written — unquoted keys, trailing commas and all, with real JSON5 parsing.
JSON5 Validator
Validate JSON5 with precise errors — and get the strict-JSON equivalent of your document in the same click.
JSON Builder
Build a JSON document field by field. Dot-notation paths create the nested objects and arrays for you, and the result is always valid — no stray commas, no unbalanced braces.
JSON Size Calculator
Measure exactly what a JSON payload costs — raw, minified, pretty-printed and gzipped bytes — and see which keys are eating the budget.
JSON Repair
Paste JSON that almost parses — single quotes, trailing commas, comments, a truncated tail — and get valid, formatted JSON back.
JSON Schema Validator
Paste a document and a JSON Schema, press Validate, and get every violation at once — each one located by its JSON Pointer path and named by the keyword that failed. Runs Ajv entirely in your browser.
JSONPath Tester
Paste a document, write an expression, and see exactly what it selects. Two dialects in one page — JSONPath for recursive descent and filters, JMESPath for projections and reshaping — evaluated entirely in your browser.
JSONL Viewer
The JSON Viewer can't open a .jsonl file at all — JSON.parse fails on line two. This page reads it the way it's actually structured: one JSON value per line.
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One workspace for every JSON task
JSON is the lingua franca of APIs, configuration, and logs — which means the same few chores come back daily: making a minified payload readable, finding the syntax error a server rejected, comparing two responses, or flattening a pretty file back to one line. Each tool here is tuned for exactly one of those jobs, and they all share the same editor, so Format, Validate, Minify, Sort, and Compare feel like tabs of a single workspace rather than separate sites.
Everything runs locally. Paste a payload with customer data or API keys and it never leaves the browser tab — there is no upload step, no server log, and the pages keep working offline once loaded. For repeated work, the editor supports file load, drag-and-drop, URL fetch, and one-click copy or download of results.
Which JSON tool do I need?
Reach for the JSON Formatter when you want readable indentation, and the JSON Validator when you need a verdict with the exact line and column of the first error. The JSON Viewer renders a collapsible tree for exploring deep structures; the JSON Sorter alphabetizes keys for stable diffs; JSON Compare shows two documents side-by-side with differences highlighted. JSON Minify and JSON to One Line go the other direction for payloads headed to production, while JSON Stringify escapes a document for embedding inside another string. If the input might be JSON5 — comments, trailing commas, single quotes — the JSON5 Formatter and JSON5 Validator accept what strict parsers reject.
Help
Frequently asked questions
Everything you need to know about the JSON Tools.
01What's the difference between formatting and validating JSON?
Formatting rewrites whitespace so the structure is readable; validating parses the document and reports whether it's legal JSON, with the line and column of the first violation. Formatting requires a successful parse, so the formatter doubles as a validator — but the dedicated validator gives clearer diagnostics when the answer is no.
02Is it safe to paste production API responses here?
Yes. Every JSON tool on this site parses and transforms entirely in your browser using client-side JavaScript — payloads are never transmitted, stored, or logged. You can disconnect from the internet after the page loads and everything keeps working.
03How large a JSON file can these tools handle?
The editor comfortably handles multi-megabyte documents; practical limits depend on your device's memory rather than any server quota. For very large files, prefer the Formatter or Minify over the tree Viewer — rendering tens of thousands of expandable nodes costs more than reformatting text.
Learn the format
Guides for json tools
TOML vs YAML vs JSON: Choosing a Configuration Format
TOML, YAML and JSON compared for configuration files: comments, types, nesting, dates, tooling and the ecosystems that chose each — with a decision guide and conversions.
6 min readGuide · JSONJSON Minify vs Gzip: What Actually Shrinks a Payload
Measured bytes for three JSON documents raw, minified, gzipped and brotlied: what minification saves once compression is on, and when it still matters.
8 min readTutorial · JSONHow to Validate JSON Against a Schema in Python and JavaScript
Validate JSON against a schema with Ajv in Node and jsonschema in Python: install, compile, read the error objects, and wire validation into CI.
9 min readGuide · Web & APIsURL Encoding Explained: %20 vs +, Reserved Characters, When to Encode
What percent-encoding does, which characters are reserved, why forms use + for a space, and how encodeURIComponent, encodeURI and URLSearchParams differ.
9 min readGuide · Developer ToolsFreeFormatter Alternatives (2026): Where Its Tools Went
FreeFormatter.com has been retired and its tool pages now return 404. A verified map of where each formatter, validator, escaper and encoder moved.
6 min readGuide · Developer ToolsJSON Crack Alternative Without Signup: Viewing JSON as a Tree
JSON Crack draws JSON as a node graph. If you want a collapsible tree with path queries instead, here is how the two compare — checked September 2026.
5 min read