FREE TOOL · DEVELOPER

Format, validate and fix JSON

JSON is how apps and AI APIs exchange data. Paste any JSON to format or minify it and get the exact line and column of errors. Then fix a broken record yourself in the challenge.

⏱ 5–10 min · Runs in your browser · No signup

You will practise

Reading JSON structure
Finding syntax errors by line and column
Knowing JSON’s strict rules (double quotes, no trailing commas)

⚙Use the tool

🔒 Runs entirely in your browser. Nothing is uploaded.

Paste JSON

{"tool":"Open Practice","free":true,"steps":["brief","make","check","improve","ship"]}

Result

✓Practice challenge

Fix this JSON so it is valid without changing the data:

{
  name: 'Tendai',
  "age": 29,
  "skills": ["Excel", "SQL",],
}

Your answer

{
  name: 'Tendai',
  "age": 29,
  "skills": ["Excel", "SQL",],
}

Questions people ask

Why is my JSON invalid?

The most common causes are single quotes, unquoted keys, trailing commas and comments — none are allowed in JSON.

Is my data uploaded?

No. Everything runs in your browser.

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