snaptools
J
JSON Validator
✓

Valid JSON

✕

Invalid JSON

paste JSON to validate
// about this tool

JSON Validator Online

Updated 2026-07-09

Validate JSON online and find syntax errors instantly, right in your browser. Paste your JSON and SnapTools checks whether it's well-formed as you type — and when it isn't, it points to the exact line and column of the first error so you can fix it fast. Nothing is uploaded; validation runs locally, so it's safe for private or sensitive data.

Catching a misplaced comma or an unclosed bracket by eye is painful in a large payload. The validator does it in milliseconds and tells you precisely where to look — whether you're debugging an API response, checking a config file, or cleaning up hand-edited JSON.

// how to use

  1. 1 Paste or type your JSON into the input panel — validation runs live as you type.
  2. 2 If anything is wrong, the status bar turns red and shows the first error with its line and column.
  3. 3 Jump to that spot, fix the issue (a missing comma, quote, or bracket), and watch it flip to "Valid JSON".

// examples

Valid JSON
Input
{"id":42,"tags":["a","b"],"active":true}
Output
Valid JSON · 3 keys · 1 array
Invalid — trailing comma
Input
{"id":42,"name":"Ada",}
Output
Invalid JSON — unexpected "}" at line 1, column 23 (remove the trailing comma)

// common uses

Debugging malformed API responses Checking a config file before deploy Pinpointing a syntax error by line and column Sanity-checking hand-edited JSON

// faq

The usual culprits are trailing commas, single quotes instead of double quotes, missing commas or brackets, and unquoted keys. The validator points to the exact line and column of the first problem.
No — this checks JSON syntax (is it well-formed), not whether it matches a schema. Schema validation is a separate concern.
Not in standard JSON. Both are common in JSON5/JSONC but are flagged here, because strict JSON does not permit them.
No. Validation happens in your browser — nothing is uploaded, so it is safe for private payloads and tokens.
Validating only tells you whether the JSON is correct and where it breaks; formatting also rewrites it with clean indentation. Use the JSON Formatter to do both at once.

// related

JSON Formatter JSON Minifier JSON Diff JSON to YAML JSON to CSV

Use this via API

Get a free API key → 
curl -X POST https://snaptools.dev/api/v1/tools/json-validator \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"json":"{\"id\":42,\"tags\":[\"a\",\"b\"],\"active\":true}"}'
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