JSON Validator
Validate JSON and detect syntax errors instantly. This page is built for invalid JSON, unexpected token failures, and parser messages that show a line, column, or character position. When the payload is valid, move to the JSON Formatter for readable output, or browse the JSON Tools hub.
Auto-validates in a worker and highlights the failing character without blocking the UI.
Paste JSON from an API response, config file, schema sample, or debugging session to validate the syntax.
Validation Result
Check the exact syntax mistake next
Most validator failures fall into a small set of repeat errors. Open the matching fix instead of scanning the whole payload blindly.
Trailing Comma in JSON
Check this first when the payload looks right except for the last property or array item.
Single quotes vs double quotes
Use this when copied JavaScript objects or config snippets fail inside strict JSON.
Unexpected token in JSON
Trace parser failures back to missing commas, malformed keys, or invalid opening characters.
Parse error line and column
Use the reported line and column as a search zone when the real mistake is slightly earlier.
Related Tools
Jump to the formatter after validation or keep the broader JSON tool cluster within reach.
JSON Formatter
Beautify raw JSON with readable indentation and a clean copy flow.
JSON Schema Validator
Validate JSON data against a JSON Schema and inspect failing rules quickly.
JSONPath Tester
Run JSONPath queries against a payload and inspect matched values with paths.
URL-encoded JSON Decoder
Decode URL-encoded payloads or query parameters back into readable JSON.
JSON to YAML
Convert valid JSON into readable YAML for config and infrastructure workflows.
JSON Minifier
Compress valid JSON into a single line by removing extra whitespace.
JSON Schema Generator
Generate a starter JSON Schema from a representative JSON sample.
JSON Diff
Compare two JSON objects and highlight the differences.
What this validator checks
Use this section to understand what the validator is checking, why an error appears, and how to fix the part of the JSON that broke.
How validation works
When you paste JSON here, the validator tries to read it the same way a browser or app would. If the text can be parsed, the JSON is valid.
If something is broken, the tool shows the parser error and points you to the line, column, or character position that needs attention.
When to use the validator vs the formatter
Use the validator first when the payload is failing, an API rejects the body, or JSON.parse or json.loads throws an error.
Use the formatter after validation succeeds and you want readable indentation, copy-ready output, or an easier way to scan the final structure.
What invalid JSON errors usually mean
- Unexpected token often means a missing comma, invalid opening character, or bad quote style.
- Line and column errors tell you where the parser noticed the structure break, which may be slightly after the original mistake.
- Quote-related failures often come from copied JavaScript objects or Python-style literals that are not strict JSON.
What the result helps you do
- Confirm whether a payload is valid before using it in code or markup.
- Jump to the part of the JSON that caused the parser to fail.
- Move directly into formatting once the syntax issues are fixed.
Privacy and browser execution
Validation runs in your browser. The JSON is checked locally in the current session instead of being posted to a remote validation service.
That keeps the workflow fast and private, though sensitive data should still be handled carefully in any browser-based tool.
FAQ
Related Guides
Short reference pages for the syntax issues and workflows around JSON formatting and validation.
How to Validate JSON
Check syntax safely and interpret parse errors faster.
Common JSON Errors
A quick reference for the mistakes that break JSON most often.
JSON Single Quotes vs Double Quotes
Learn which quotes are valid in JSON and why copied JavaScript objects often fail.
JSON Parse Error Line and Column
Use line and column information to find the real JSON syntax mistake faster.
Invalid JSON Examples
Broken snippets with fixes so you can spot failure patterns quickly.