# Test-Json > Test whether a string is a valid JSON document. > This command can only be used through PowerShell. > More information: . - Test if a string from `stdin` is in JSON format: `'{{string}}' | Test-Json` - Test if a string JSON format: `Test-Json -Json '{{json_to_test}}'` - Test if a string from `stdin` matches a specific schema file: `'{{string}}' | Test-Json -SchemaFile {{path\to\schema_file.json}}`