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JSON Validator

100% Free

Validate JSON in real time with structural diagnostics — node count, max depth, type counts, and precise parse-error location.

Real-time
Client-Side
RFC 8259
Paste JSON above to validate.

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  • Responsive design
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<iframe
  src="https://tools.town/embed/json-validator/"
  width="100%"
  height="600"
  style="border:none; border-radius:12px;"
  loading="lazy"
  title="JSON Validator">
</iframe>

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How to Use

  1. 1 Paste any JSON into the input box
  2. 2 Valid JSON shows green check + structural stats
  3. 3 Invalid JSON shows the error with line + column
  4. 4 On error, the offending snippet is highlighted for inline debugging

Features

  • Real-time validation as you type
  • Structural stats — total nodes, max depth, type counts
  • Parse errors with line + column extracted from the message
  • Snippet of the offending position for fast debugging
  • Identifies the root type (object, array, primitive)
  • 100% client-side

Why it Matters

When an API returns 'unexpected end of JSON input' on a 5MB payload, finding the bad character by hand is painful. This validator pinpoints the exact line and column, surfaces the surrounding snippet, and tells you the structural shape of the rest — no copying into a Node REPL required.

★★★★★

Use Cases

API Response Debug

Find the bad character in a malformed API response

CI Pipeline Check

Validate config files before they hit production

Schema Spot-Check

See node count + depth before designing a schema

Frequently Asked Questions

What's the difference between this and the JSON Formatter?
Both validate. The Formatter additionally pretty-prints / minifies / sorts keys. This Validator focuses on yes/no + structural diagnostics (node count, depth, type counts).
Does it support JSON5 (single quotes, comments, trailing commas)?
No — strict RFC 8259 only. JSON5 is a different spec; if you need it, use a JSON5-aware parser like the json5 npm package.
Why is the line/column missing for some errors?
The browser's JSON.parse error format varies. V8 (Chrome/Node/Edge) includes 'at position N'; some other engines don't. We extract whatever's available.
Can I validate against a JSON Schema?
This tool only checks syntax. For JSON Schema validation use Ajv or a similar library — those are heavier and out of scope for a browser tool.
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Browse all guides →
How to Use JSON Validator
json

How to Use JSON Validator — Complete Guide

Learn how to validate JSON syntax, find errors instantly, and understand common JSON mistakes using Tools.Town's free JSON Validator.

8 May 2026

5 min read

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