JSON Validator
Client-sidePopularValidate JSON instantly in your browser. See type, size, and node counts — or exact parse errors with line and column.
Processed in your browser — data stays on your device
About JSON Validator
JSON Validator checks whether your document is syntactically valid and reports useful structure stats when it is.
When validation fails, you get a clear parser message with line and column guidance so you can fix trailing commas, missing braces, and other common issues.
Features
Instant validation
JSON is checked automatically as you paste or type.
Structure report
See type, node count, character count, and UTF-8 byte size.
Precise errors
Invalid documents highlight line/column whenever the parser provides them.
Exportable report
Copy or download a plain-text validation report for tickets and reviews.
How it works
Paste or upload JSON
Drop a file or paste JSON into the input panel.
Validate automatically
Valid documents show a report with type and size. Invalid ones highlight the error location.
Copy or download the report
Export the validation summary for debugging or reviews.
Example walkthroughs
Valid payload
A valid object reports type object plus node and size metrics.
{"ok":true,"count":2,"items":["a","b"]}Invalid trailing comma
Trailing commas are invalid in JSON and surface as a parse error.
{"ok":true,}
Use cases
QA API contracts
Verify fixtures and mocked responses before running integration tests.
Support triage
Confirm whether a customer-provided payload is syntactically valid.
CI sample checks
Quickly lint sample JSON used in docs or seed data.
Frequently asked questions
Does validation send my JSON to a server?
No. Validation runs entirely in your browser using the native JSON parser.
What does the report include?
For valid JSON: type, node count, character count, and UTF-8 byte size. For invalid JSON: the parser message with line and column when available.
Is duplicate key detection supported?
Browsers follow JSON.parse rules, which keep the last duplicate key. Structural validity is still reported.
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JSON Viewer
Explore JSON as an interactive tree with paths, types, and expandable nodes — all processed locally in your browser.
JSON Compare
Compare two JSON documents structurally. Find added, removed, changed, and type-changed paths — privately in your browser.
JSON Diff
Generate a unified diff of two JSON documents after pretty-printing. Ideal for reading line-level changes quickly.
JSON Escape
Escape text into a JSON string literal, or unescape a JSON string back to raw text — instantly and offline.