EN

JSON Validator

Check whether your JSON is valid. If it is not, you see the line and column of the problem together with the surrounding lines, so you can fix it in seconds.

Your files never leave your device. Everything runs in your browser.

How it works

  1. Add your JSONPaste it, type it, open a file or drop it onto the input box. Try Sample if you just want to look around.
  2. Check the resultThe result on the right updates as you type. Errors are shown with the line and column.
  3. Copy or downloadCopy the JSON with one click or download it as a file.

Find JSON errors quickly

A single missing comma or an extra bracket is enough to make a whole file unreadable for a program. Instead of a cryptic message, the validator marks the line and the exact position where the problem starts.

Valid JSON gets a short summary with the number of keys, objects and arrays and how deep the structure goes.

About JSON

JSON (JavaScript Object Notation) is a text format for structured data. It uses objects with keys and values, arrays, strings, numbers, true, false and null. Almost every web API and many configuration files use it because both people and programs can read it easily.

Frequently asked questions

Are comments allowed in JSON?

No. Standard JSON does not support comments. Remove lines starting with // or blocks between /* and */ before validating.

Why are single quotes an error?

JSON only accepts double quotes around keys and text values. Replace single quotes with double quotes.

Is my data uploaded anywhere?

No. Everything runs in your browser. Your JSON and CSV data is not sent to our servers.

How big can my JSON be?

Files of several megabytes work well. Very large files depend on your device's memory. Coloring is turned off for very large results to keep the page responsive.

Why does the tool say my JSON is invalid?

Common causes are a missing comma, a trailing comma before a closing bracket, single quotes instead of double quotes, or comments. The error box shows the line and column so you can fix it quickly.

Does it work without an internet connection?

Yes. After you open the page once, it keeps working even if your connection drops.