Simple online tools for developers, networking, text and conversions.
Developer Tools
JSON Validator Guide
Learn when to use JSON Validator, how to use it correctly, and how to avoid common mistakes.
What this guide covers
Use this free JSON validator to quickly test whether your JSON is syntactically correct. It is useful when checking API payloads, config files, request bodies, or copied JSON that may contain commas, quote issues, or broken brackets.
This guide explains when to use JSON Validator, how to get a cleaner result,
and which mistakes to avoid before moving on to related tools or the main tool page.
Why use JSON Validator
Checks JSON before you send it to an API or app.
Helps catch syntax mistakes early during testing.
Useful for request bodies, configs, and exported data.
Gives a quick pass or fail result without extra tools.
Works well for one-off checks directly in the browser.
How to use JSON Validator
Paste your JSON into the input field.
Run the validator to test the syntax.
See whether the content is valid or invalid.
Fix errors in the source JSON and test again if needed.
Best use cases
Checking API request or response payloads before debugging.
Testing JSON copied from logs or documentation.
Validating app or server config files before deployment.
Common mistakes
A trailing comma is left after the last property.
Fix: Remove the extra comma at the end of the object or array.
Object keys are missing double quotes.
Fix: Wrap each key in double quotes to match JSON syntax.
A closing bracket or brace is missing.
Fix: Check that every opening symbol has a matching closing symbol.
Use the tool
Ready to run JSON Validator? Open the main tool page to enter your input,
generate the result, and copy or download the output.