Validate, format, and transform JSON, then generate TypeScript, Python, Java, Go, or Zod types straight from it — entirely in your browser, nothing sent to a server.
Yes. The JSON Validator runs entirely in your browser using JavaScript. Your JSON payloads are never transmitted to our servers or any third party, making it secure for validating sensitive enterprise configurations or API responses.
Yes. The validator checks your JSON strictly against RFC 8259 — the official specification for JSON interchange format. It catches syntax errors such as trailing commas, unquoted keys, missing brackets, and invalid escape sequences.
Absolutely. Paste any minified single-line JSON string and the formatter will indent and beautify it for readability while simultaneously checking its structural validity. You can also compare two JSON documents side-by-side using the Diff tab.
Yes. Open Generate Code and pick the YAML tab to convert JSON to YAML (or paste YAML underneath to convert it back to JSON), or the CSV tab to convert an array of objects into rows. CSV export is built for flat or shallow data — nested objects/arrays are JSON-stringified into the cell rather than expanded into extra columns.
Yes, with the Validate Schema button — paste a draft-07-style schema and see pass/fail with specific violated-rule messages. It's a lightweight, hand-written validator covering the most common keywords (type, required, properties, items, enum, minimum/maximum, minLength/maxLength, pattern, minItems/maxItems); it does not implement the full draft-07 specification (no $ref, allOf/anyOf/oneOf, format, etc.).
Yes. When your JSON fails to parse, the panel below the editor shows a plain-English explanation — trailing comma, missing comma, unquoted/single-quoted key, unterminated string, unexpected end of input, or a control character in a string — along with the exact line/column and a highlighted snippet, in addition to the one-click "Apply Fix" suggestions. This is rule-based pattern matching against the parser's error message, not an AI call.
JSON validation uses the browser's native JSON.parse() method, which strictly follows RFC 8259. Common errors include: missing or extra commas, unquoted keys, single quotes instead of double quotes, trailing commas, and unescaped special characters in strings.
Pretty printing adds consistent indentation (2 or 4 spaces) and newlines to make JSON human-readable. Minification removes all whitespace to reduce file size — useful before transmitting JSON over a network or embedding in production code. Neither changes the data; only the whitespace format differs.
JSONPath lets you extract values using dot notation (e.g., $.user.name) or bracket notation (e.g., $["items"][0]["id"]). The $ represents the root object. Use [*] to iterate all items in an array.
JSON does not support comments, trailing commas, or undefined values. Numbers cannot have leading zeros. All strings must be double-quoted. Valid types are: string, number, boolean, null, array, and object.
When your JSON fails to parse, the "What's Wrong & Quick Fixes" panel below the editor matches the browser's raw JSON.parse() error message and the text around the reported position against a fixed set of rules — it is not an AI call. It recognizes trailing commas, single/unquoted keys, missing commas between properties, unterminated strings, unexpected end of input, and control characters inside strings, and explains each in plain language with the exact line/column and a highlighted snippet. Duplicate object keys are detected separately, since they are technically valid JSON — JSON.parse() just silently keeps the last value and drops earlier ones.
YAML output/import uses js-yaml, a widely-used open-source YAML 1.2 parser, loaded from cdnjs. Open Generate Code → YAML to convert your JSON to YAML, or paste YAML into the box underneath that tab to convert it back into JSON in the left editor.
CSV export (under Generate Code → CSV) handles the common case of a JSON array of flat or reasonably shallow objects: each object becomes a row, and the union of all object keys becomes the column headers. Nested objects and arrays are not exploded into extra columns — a nested value is JSON-stringified directly into its cell (e.g. an "address" object becomes the text {"city":"..."} in one cell) rather than crashing the export. This is a hand-rolled converter meant for simple, mostly-flat data; deeply nested or irregular structures will produce cells full of stringified JSON.
The Validate Schema panel checks your JSON against a pasted schema using a hand-written, lightweight validator — it is not a full draft-07 implementation and does not aim to be Ajv-level complete. Supported keywords: type, required, properties, items, enum, minimum/maximum, exclusiveMinimum/exclusiveMaximum, minLength/maxLength, pattern, and minItems/maxItems. Not supported: $ref, allOf/anyOf/oneOf/not, if/then/else, format, additionalProperties, patternProperties, uniqueItems, dependencies, const, and other draft-07 keywords. For full-spec validation, use a dedicated library such as Ajv in your own codebase.
Save snippets, custom schema presets & validation history — coming soon for logged-in users