JSON Validator
Validate JSON and get the exact location of the first error, with hints for common mistakes. Valid JSON shows useful structure stats — all in your browser.
About the JSON validator
Paste JSON and Bytewrench checks whether it's valid, pinpointing the exact line, column and surrounding context of the first error so you can fix it fast. When the JSON is valid, it reports useful stats — root type, total keys, maximum nesting depth and size.
If parsing fails, it also flags the most common culprits — trailing commas, single quotes, unquoted keys and comments — to point you straight at the problem. Everything runs locally in your browser.
Live valid/invalid status as you type or paste.
Exact line and column with a context snippet and caret.
Detects trailing commas, single quotes, unquoted keys and comments.
Root type, key count, max depth and byte size for valid JSON.
Frequently asked questions
What makes JSON invalid?
Frequent causes are trailing commas, single quotes instead of double, unquoted object keys, comments, and missing brackets or commas. The validator highlights the first error's location and flags these patterns.
Does it validate against a schema?
This tool checks JSON syntax. For schema validation against JSON Schema, use the JSON Formatter's Schema tab.
Is there a size limit?
It runs in your browser, so very large documents are limited only by your device's memory; typical API payloads and config files validate instantly.
Is my JSON uploaded?
No. Validation happens entirely in your browser.