JSON Formatter & Validator Online — Pretty Print, Minify, Find Syntax Errors
Format and validate JSON
Format, validate, and minify JSON in one click with a real-time syntax-highlighted preview that pretty-prints nested objects and arrays. When validation fails, the tool pinpoints the exact location with an "Error at line X, col Y" message and renders the offending line with a caret beneath the bad character — even on newer V8 engines where the native "at position N" hint was removed, a custom tokenizer fallback keeps the position accurate. Validate JSON-LD schema markup before publishing it to Google for rich results, debug API responses and webhooks, or tidy up config files like tsconfig, package.json, and .eslintrc. Drop in a .json or .txt file to process large payloads without a server round-trip. Everything runs 100% locally in your browser — your API keys, tokens, and payloads never leave your device.
Validate JSON-LD schema before search engines crawl it
Google rich results — FAQ, product, breadcrumb, how-to — silently ignore any JSON-LD block that contains a trailing comma, an unescaped quote, or a missing bracket, so a single typo in a Schema.org template can cost you a featured snippet overnight. Paste the markup and the formatter returns a cleanly indented, syntax-highlighted version or, on failure, the precise line and column of the offending token with the source line and a caret pointing at the bad character. Use it before every deploy to keep structured data eligible for rich results.
Pinpoint JSON errors to the exact character, locally
Newer V8 engines no longer include position metadata in JSON parse errors, so a custom tokenizer fallback walks the input and reports "Error at line X, col Y" with the offending line echoed back and a caret underneath. Upload a .json or .txt file directly when the input is too large to paste — everything is parsed in your browser with no upload to a third-party linter. That makes the tool safe to run against API responses, webhook payloads, and config files that contain credentials.