Coding and developer tools

Free JSON Validator and Formatter.

Syntax validation, error locations and formatted JSON.

Inspect and format a supplied JSON document while keeping syntax findings separate from assumptions about its intended application.

Chrome extension + account required.
25 free automation tasks/month across tools. Browser-provider limits apply.

WHAT TO HAVE READY

JSON text.

YOUR STARTING POINT

A task you can make yours.

Copy it here. Paste it into WebAct when you are ready.

This page prepares your prompt. The task runs in WebAct.

01

Make the task yours.

Review the prompt above. Add your goal and any requirements that matter.

02

Bring it to WebAct.

Open WebAct, paste the task and provide the data and rules. Review any proposed calculation or code action before approving it, then check a known example.

03

Check the useful part.

Check formulas, code and calculations against known inputs in the appropriate runtime. Review actions before execution and keep the original data available.

A PRACTICAL GUIDE

How to use the JSON Validator and Formatter.

JSON validation should use a parser and report the actual error location. Formatting is separate from checking an application-specific schema.

Make the workflow fit your task.

Parse the exact input to identify syntax errors, then format valid JSON without changing values. Keep application-schema validation separate and report the location and reason for the actual parser failure.

What you provide
JSON text.
What you get
Syntax validation, error locations and formatted JSON.

See the input and the result.

Illustrative input and output · a teaching example, not a live WebAct run

Example input

Input: {"active": true,}

Completed example

The trailing comma is invalid JSON. Corrected input: {"active": true}.
Download this example

Load this input into the prompt, then copy it to WebAct to try the task. Your result may differ from the illustration.

Decisions and troubleshooting.

Does valid JSON mean the data satisfies my API contract?

No. Syntax validation only establishes that the JSON can be parsed. Required fields, types and business rules need separate checks.

Why does text that looks like a JavaScript object fail JSON parsing?

Check quoted property names, trailing commas and unsupported values or comments. JSON has its own syntax rules.

Try it with your own source.

Replace the example with your material in the task prompt. Keep the requirements you need, then copy the task into WebAct.

Customize and copy the task ↑
BEFORE YOU BEGIN

Using WebAct.

The prompt and example are available here. Run your task in the WebAct Chrome extension.

Is this tool free?

You can copy and edit the prompt here for free. To use it with WebAct, install the Chrome extension, create and verify your account, and connect an available browser ChatGPT session. The Free plan includes 25 user-started automation tasks per calendar month, shared across tools. Ordinary browser Chat is separate; provider limits apply.

Learn about shared context in our privacy policy and choosing Chat or Task.

FROM A PROMPT TO YOUR OWN WORK

Bring the task to your page.

Install WebAct, add your source material and make the result yours.

Install WebAct