Best for
Checking whether JSON text can be parsed before using it in an API, configuration file or conversion workflow.
Private browser tool
JSON Validator
Validate JSON syntax free in your browser. Find parsing errors without uploading API responses, configuration data or other private JSON.
✓ Local processing✓ No uploads✓ No account
JSON→RESULT
- 1Add input
- 2Choose options
- 3Get result
Next step
Continue working with your file
Simple by design
From file to result in three steps
- 1
Paste the JSON you want to check.
- 2
Select Validate JSON.
- 3
Use the reported parser message to correct the syntax, then validate again.
Practical guidance
When to use Validate JSON
What you get
A clear valid or invalid result with the browser parser error when the syntax cannot be read.
Useful tip
Syntax validation does not enforce a JSON Schema. A document can be valid JSON while still missing fields required by your application.
Start with the first parser error
A missing quote or comma can cause several later characters to look incorrect. Fix the earliest reported problem, then validate again instead of trying to solve every apparent issue at once.
Valid syntax is only the first step
After the document parses, check that field names, allowed values and data types match the system that will receive it. Those requirements belong to that system or its JSON Schema.
Good to know
Frequently asked questions
What does this JSON validator check?+
It checks JSON syntax: matching braces and brackets, valid strings, commas, numbers, literals and the overall document structure.
Does it validate against a JSON Schema?+
No. It does not check required properties, types defined by a schema or business rules.
Why are single quotes rejected?+
JSON strings and property names require double quotes. Single-quoted strings are common in JavaScript but are not valid JSON.
Are comments allowed in JSON?+
No. Standard JSON does not allow line or block comments. Remove them before validation.
Does my file leave my device?+
No. This tool processes your file inside your browser and does not send its contents, name or metadata to Filemivo.
Is Validate JSON free?+
Yes. It is free to use and has no artificial file-size limit. Your browser and device memory determine the practical limit.