Instantly verify JSON syntax compliance, pinpoint the exact line and column of any parse error, and repair trailing commas, single quotes, unquoted keys, or comments in one click.
Fast, secure, and 100% free in your browser. No registration, file watermarks, or software downloads required.
Upload Document to JSON Validator
Select or drag and drop your file here. Safe, private, and instant.
Follow these three straightforward steps to complete your document workflow in seconds:
Paste your JSON payload or upload a .json file into the validator workspace.
If a syntax error exists, the validator highlights the exact line number, column number, and offending character.
Use the 'Auto-Fix Syntax' button to automatically repair trailing commas, single quotes, and comments, then copy or download the valid JSON.
Displays the exact line and column number with a visual caret pointer where JSON parsing failed.
Automatically removes trailing commas, strips JS comments, converts single quotes to double quotes, and quotes unquoted keys.
Inspect total key count, maximum nesting depth, object count, and array count in real time.
Validates strictly against IETF RFC 8259 / ECMA-404 standards in your browser or via POST /api/v1/pdf/json-validator.
Developers can integrate JSON Validator directly into applications and backend pipelines via POST https://goodpdftools.com/api/v1/pdf/json-validator. API usage requires an X-API-Key header.
Generate your API Key & view JSON Validator REST API Documentation →
File handling depends on the tool. See our Privacy Policy for details about processing and retention.
Learn more in our Privacy Policy and Terms of Service.
Unlike JavaScript objects, strict RFC 8259 JSON forbids trailing commas after the last item in an object or array. Click 'Auto-Fix Syntax' to remove trailing commas automatically.
Yes! Clicking 'Auto-Fix Syntax' converts single-quoted strings and keys into standard double-quoted JSON strings and wraps unquoted object keys in double quotes.
No. In-browser validation runs 100% locally inside your browser using native JavaScript parsing so confidential API payloads never leave your machine.
Yes! Call POST /api/v1/pdf/json-validator with your X-API-Key header to receive a structured validation report including valid status, key counts, and error details.
Rated 4.8 out of 5 based on 1313 verified user ratings:
“Used JSON Validator Online on GoodPDFTools for our daily document and API payload workflow. Instant browser processing with zero formatting loss and no watermarks.”
“The JSON Validator Online studio and its /api/v1/pdf REST endpoint saved our engineering team hours of manual work. Fast, accurate, and Core Web Vitals are super responsive.”
“100% free, clean interface, and works directly in Chrome without installing heavy desktop software. Highly recommend JSON Validator Online.”
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