JSON Validator
Check your JSON for syntax errors and structural validity. Get detailed error messages and line numbers.
Last updated: April 28, 2026
Waiting for input...Tool Settings
Waiting for Input
Paste content to start linting
- Double quotes for keys
- No trailing commas
- Correct nesting of brackets
- Valid primitive types
All processing happens locally in your browser. Large files are handled in memory and never uploaded to any server.
JSON Validator
Debug your JSON data with our professional JSON Validator. It performs a deep scan of your JSON structure to ensure it follows the RFC 8259 standard. If an error is found, the validator provides the exact line number and a descriptive message (e.g., 'Missing comma', 'Unterminated string') so you can fix it instantly. It also supports checking for common pitfalls like trailing commas which are invalid in standard JSON. The validator walks nested structures of any depth, confirming that every object and array closes properly and that every value uses a legal type, so mistakes buried far down a data tree are still caught. Failures are reported with line and column positions plus the offending token, so you know exactly where parsing stopped. Validation runs entirely in your browser, so large or sensitive payloads are checked without ever being uploaded.
Why This Tool Exists
What makes this useful — and why I built it this way.
Syntactic Checkups: Detect syntax errors, missing brackets, or bad quotes in JSON.
Detailed Error Flags: Pins precise line numbers where formatting rules are broken.
Interactive Validation: Validates code strings instantly as you write or paste.
Private Checking: Validation runs locally; your payloads are never uploaded for checking.
When You'd Use This
Real situations where this tool saves the day.
Config Debugging: Troubleshoot why project config files fail to load.
Data Integration Prep: Validate custom JSON feeds before feeding them to databases.
Learning Tool: Clean up nested structures and identify formatting mistakes.
Pre-Deployment Checks: Validate environment configuration JSON before shipping a release.
Using JSON Validator
It's straightforward — here's how it works.
Paste the JSON you want to verify into the validator.
Check the 'Status' indicator (Green for Valid, Red for Invalid).
If invalid, look at the error list to see the line, column, and offending token.
Fix the errors in the editor and wait for the status to turn green.
Copy or download the validated JSON once it passes.
Questions People Ask
Honest answers about how this works.
Does it support JSONC (JSON with comments)?
Honestly? Standard JSON does not support comments. Our validator adheres to strict JSON standards, but we provide an option to 'Ignore Comments' if needed for development files.
Does it check more than just syntax?
Yes. Beyond basic parsing, the validator checks that every value is a legal JSON type, that objects and arrays close properly at any nesting depth, that commas are placed correctly, and that strings contain no unescaped control characters or broken escape sequences.
Is my JSON uploaded for validation?
No. Validation happens locally in your browser using a streaming parser, so nothing is transmitted. Private API responses, database exports, and configuration files containing secrets can be checked safely without a copy leaving your device, and the tool works even when you are offline.
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