JSON & data

JSON validator

Validate JSON syntax with line-precise errors, instantly.

JSON Diff tab · or Tools → Inspect → Validate syntax · 7-day free trial · Premium $9.99 / yr

Try it now·runs locally · nothing uploaded

Input✓ valid

Output

{
  "id": 42,
  "name": "Alice",
  "tags": [
    "engineer",
    "admin"
  ],
  "address": {
    "city": "Oslo",
    "zip": "0150"
  }
}

Want side-by-side JSON diff, JSONPath, and instant access from any tab?Install free trial →

★ Premium

Built for the things AI can’t fake

This tool runs free, right here. The extension adds three things a web widget can’t:

Start 7-day trial→

★ Flagship

Playground

↗

JS / TS scratchpad — sandboxed and instrumented.

Paste real code, hit Run. Console + network monitor + watch expressions all in one panel.

·Real ES modules · top-level await
·URL imports — esm.sh & friends
·Live fetch monitor (every call)
·Watch expressions in your scope
·10s sandbox timeout · zero CORS pain

HTTP client

↗

Postman-style request runner.

Save collections, share variables, hit any API. Includes GraphQL with introspection, OpenAPI / cURL import.

·Bearer / Basic / API-key auth
·GraphQL · introspection
·OpenAPI 3.x · cURL import
·Copy as fetch / axios / Python

Realtime (WS + SSE)

↗

Stream-protocol tester — what Postman doesn’t do well.

WebSocket + Server-Sent Events with custom auth headers, auto-reconnect, JSON pretty-print.

·wss:// + ws:// + subprotocols
·SSE via fetch — Authorization works
·Auto-reconnect with backoff
·Send composer · ⌘ + Enter

What it does

JSON syntax is unforgiving — a stray trailing comma or unquoted key, and the whole document fails to parse. A validator tells you precisely which line broke and why.

VibeGear validates as you type. The pane lights up green for valid JSON; red with the error message and line number when it’s not.

Why use VibeGear's json validator

✓Live validation — no "Validate" button to click
✓Errors include line and column numbers
✓Works the same way for YAML, XML, JS, and TS in the Validate syntax tool
✓Fully local

How to use it

1Open the JSON Diff tab.
2Paste your JSON. The pane border turns red on syntax errors.
3Read the error pill below — it includes the message your runtime would have produced.

Frequently asked

What JSON spec is supported?

Standard JSON (RFC 8259). No comments, no trailing commas. If you need a more permissive parser, format the document elsewhere first.

Related tools

JSON formatter & validator

Pretty-print, validate, and explore any JSON — locally, in your browser.

JSON Schema validator

Validate any JSON against any JSON Schema, live.

Syntax validator

Validate JSON, YAML, XML, JavaScript, or TypeScript syntax with line numbers.

★ Premium

One install. Every tool above.

7 days free, then VibeGear Premium is $9.99 / €9.99 per year. Everything runs locally.

Install & start trial →→