Does it check against a schema?

No — this checks that the JSON parses at all, and shows the first error. For structure, generate a schema with the JSON Schema Generator.

Never. It's a validator: invalid input is the expected case, so it reports rather than crashes.

validators · free tool

JSON Validator

Check whether JSON is valid and see the first error.

Runs in your browser — your data never leaves it

Input

Paste, type, or drop a file. Runs as you type.

Output

Output appears here as you type.

Input

{"a":1}

Output

✓ Valid JSON

This example is one of JSON Validator's test cases — if the tool stopped producing this output, the build would fail.

Does it check against a schema?: No — this checks that the JSON parses at all, and shows the first error. For structure, generate a schema with the JSON Schema Generator.
Does it ever throw?: Never. It's a validator: invalid input is the expected case, so it reports rather than crashes.

Check whether XML is well-formed and see exactly where it breaks.