Valid JSON rules
JSON uses double-quoted property names and strings. Objects use braces, arrays use brackets, and items are separated by commas. Trailing commas are not valid JSON.
Formatting versus minifying
Formatting adds whitespace and indentation for people. Minifying removes unnecessary whitespace for compact transfer or storage. The underlying data should remain equivalent.
Common errors
Watch for missing commas, unmatched braces, single-quoted strings and unescaped characters.
Paste data into the JSON Formatter & Validator to check syntax locally in your browser.
Quick answer
Format, minify and validate JSON in your browser. Use the values and units shown by the tool, review the result, and keep the original inputs available if you need to compare another scenario.
Practical checklist
- Confirm the units, dates, rates or source values before calculating.
- Use consistent units and avoid rounding intermediate values too early.
- Run a second scenario when you need to understand how one input changes the result.
- For regulated fees, taxes, provider rules or professional decisions, verify the current official rule before relying on the result.
Try the related ToolViso tool
Use the JSON Formatter & Validator to check the calculation or conversion directly in your browser. No signup is required.
Frequently asked questions
Is my JSON sent to the server?
No. The formatter runs in your browser.
Is JSON allowed to use single quotes?
Standard JSON strings and property names use double quotes. Single quotes are common in some programming languages but are not valid JSON syntax.
Does formatting JSON send it to the server?
ToolViso's JSON formatting tool is designed to run in the browser, so the text can be processed locally.