Check whether your JSON is valid and see exactly where any error is.
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The validator parses your JSON as you type, using the same strict JSON rules as every browser and API. If something is wrong you get the error message with its line and column, so a missing quote or a trailing comma takes seconds to find. Valid JSON gets a summary of its type, size and top-level structure.
Check a response body before you debug the code that reads it.
Catch a stray comma in package.json, tsconfig.json or app settings before deploying.
Validate test fixtures and mock data you typed by hand.
The most common causes are trailing commas, single quotes instead of double quotes, keys without quotes, comments, and unescaped line breaks inside strings. Standard JSON allows none of these.
Yes. You get the error message with the line and column of the first problem, so you can go straight to it.
No. It checks standard JSON (RFC 8259), the format APIs and JSON.parse expect, so comments and trailing commas are reported as errors.
No. Everything runs in your browser; nothing you paste or upload is sent to our servers.
Files up to 10 MB can be uploaded. Very large documents may take a moment because everything runs on your device.