Validate, format and check JSON Schema — entirely in your browser.
Paste or upload JSON
Auto-validates as you type
Input JSON
JSON document
JSON Schema (Draft-07)
Why this JSON validator
Privacy by design
All validation, formatting and schema checking runs in your browser. Your JSON never reaches our server. Verifiable in your devtools' Network tab.
Pinpoint errors
Syntax errors show the exact line and column with a snippet pointing to the problem character — not just a vague "unexpected token".
JSON Schema (Draft-07)
Validate documents against JSON Schema with the AJV engine. Common formats like email, uri, date and date-time are supported out of the box.
Format & minify
Beautify JSON with 2-space, 4-space or tab indentation. Sort keys alphabetically for stable diffs. Minify to remove every unnecessary byte.
Real-time validation
The Validate tab checks your JSON as you type, with a 400 ms debounce so you're never wrestling with the cursor.
No signup, no ads in your data
Free to use, no account required, no usage limits. Display ads pay the bills — but they never see what you validate.
How to validate JSON in three steps
Choose a tab — Validate for syntax checking, Format & Minify to beautify or compress, or JSON Schema to verify document structure.
Paste or upload your JSON — drop the contents into the textarea, or click "upload file" to load a .json file from disk. Nothing leaves your browser.
Read the result — a green badge confirms valid JSON; a red badge lists each error with its line, column and a snippet pointing to the problem.
Frequently asked questions
JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format derived from JavaScript object syntax. It is language-independent and is the de facto standard for REST APIs, configuration files, and data exchange on the web. It supports six data types: object, array, string, number, boolean, and null.
JSON validation checks whether a string is syntactically valid JSON — correct brackets, commas, quoting and escape sequences. JSON Schema validation goes further: it verifies that a valid JSON document also conforms to a specific structure such as required properties, data types, value ranges, string patterns, array constraints and conditional rules. Use the Validate tab for syntax, the Schema tab for structural validation.
These errors usually mean a syntax problem at the reported position. Common causes: a missing or extra comma, an unquoted property name, single quotes instead of double quotes, a trailing comma in an array or object, comments (which JSON does not support), or unescaped control characters in a string. The validator shows the exact line and column so you can jump straight to the problem.
Yes, completely. All validation, formatting and schema checking happens in your browser using JavaScript. Your JSON content is never uploaded, transmitted, or stored on any server. You can verify this by opening your browser's developer tools and watching the Network tab while you validate — you'll see no request containing your JSON.
The Schema tab uses AJV 8 with Draft-07, the most widely adopted JSON Schema draft. Common formats (email, uri, date, date-time, ipv4, etc.) are validated via ajv-formats. Older Draft-04 and Draft-06 schemas usually still work in lenient mode; Draft 2019-09 and 2020-12 may require minor adjustments such as replacing $ref placement.
Formatting (also called beautifying or pretty-printing) adds whitespace, line breaks and indentation so the JSON is readable for humans. Minifying removes all unnecessary whitespace to produce the smallest possible representation, ideal for transmission over the network or for inlining in HTML attributes. Both produce semantically identical JSON — only the whitespace differs.
No. This tool validates strict JSON as defined by RFC 8259. JSON5 (which allows comments, trailing commas and unquoted keys) and JSONC (used in VS Code config files like tsconfig.json) are not RFC-compliant JSON and will fail validation. Convert them to strict JSON first by removing comments and trailing commas.
There is no hard limit, but JSON files larger than a few megabytes may cause your browser to feel sluggish, especially during formatting. The validator itself can handle files up to roughly 50 MB on a modern desktop browser; mobile devices have less headroom. For very large files, consider a desktop tool like jq.