JSON Validator
JSON Validator — Check JSON syntax with clear error messages. Inspect valid data, format it, or download a copy.
From open to done.
Choose your input
Open JSON Validator; validate is selected for you.
Make it yours
Choose indentation and Format, Minify, Validate, or Tree.
Take it with you
Copy the result or download a .json file.
Get a better result.
JSON requires double-quoted strings and keys, and does not allow comments or trailing commas. Validation checks syntax, not an application schema. Native JSON parsing represents numbers as JavaScript numbers; very large integers may lose precision and should be encoded as strings.
JSON Validator begins with validate. The compact object {"name":"Klyvero","free":true} formats into multiple indented lines. Minify removes that whitespace while retaining the same structure.
Made for your everyday work
Processed entirely on your device
Free to use, with no signup
Copy or download your result
Works in a modern browser
When this helps
Make an API response readable, inspect a fixture, or validate a pasted configuration. The tree view helps explore nested arrays and objects without sending potentially sensitive payloads away.
A little more clarity.
What to know before you go.
What does JSON Validator set up for me?
JSON Validator — Check JSON syntax with clear error messages. Inspect valid data, format it, or download a copy. The underlying tool remains available through the parent link.
Can I adjust validate?
Yes. The preset is a starting point, and the controls remain editable. Review your result before saving.
When should I use the main json formatter tool?
Use the main tool when you want to start without this preset or choose a different task setting.
Can I include comments?
No. This tool accepts standard JSON, not JSON5 or JavaScript object literals.
Are big integers preserved?
Numbers outside JavaScript’s safe integer range may change when parsed. Store large identifiers as strings.
Useful shortcuts
Open the main JSON Formatter JSON MinifierYour next useful thing.
Base64 Encode / Decode
Convert UTF-8 text or files to Base64, and decode them back.
Developer toolText Diff Checker
Compare two versions of text with clear word-level changes.
Text toolUnix Timestamp Converter
Convert Unix seconds or milliseconds to a readable date, or a date to epoch time.
Developer toolUUID Generator
Generate UUID v1, v4 or v7, individually or in bulk.
Developer tool