JSON Formatter & Validator Online — Pretty Print, Minify, Find Syntax Errors
Format and validate JSON
Browse tools
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.
Frequently Asked Questions (FAQ)
Three operations: Format pretty-prints minified JSON with proper indentation, Validate reports whether the input is well-formed, and Minify strips all whitespace to produce a single-line string for production use. All three are available as one-click buttons above the input.
When the JSON is invalid, the tool reports the exact line and column of the offending token — for example, "Error at line 4, col 13" — and echoes the offending source line with a caret (^) pointing at the bad character. A custom tokenizer fallback handles newer V8 engines that no longer include position metadata in their parse errors.
Yes. The tool accepts .json and .txt file uploads. The file is parsed locally in your browser — nothing is uploaded to a server. This is useful for inspecting large API response dumps or configuration files.
Yes. The formatted output is syntax-highlighted with distinct colors for keys, strings, numbers, booleans, and null, which makes it easier to spot missing commas, mismatched braces, and quoting errors at a glance.
Yes. Paste any JSON-LD block — FAQ, Product, BreadcrumbList, HowTo — and the validator will catch trailing commas, unescaped quotes, and missing brackets before search engines crawl the page. This helps keep structured data eligible for rich results.
No. Every format, validate, and minify operation runs locally in your browser. The tool is safe to use on API responses, webhook payloads, and config files that contain credentials.
Yes. Switch the output to Tree mode and the parsed document is rendered as an interactive tree: every object and array becomes a node you can expand or collapse, with the first two levels open by default. Copying while in Tree mode puts the formatted JSON on your clipboard. The tree makes deeply nested API responses and config files easy to navigate.
Yes. The output mode buttons convert the parsed JSON into YAML, CSV (for arrays of objects, ready for a spreadsheet), and XML with a declaration — on top of the formatted and minified JSON modes. The download button saves the current output with the matching extension: .json, .yaml, .csv, or .xml. Every conversion runs locally in your browser.