Validators for resource files

How do check JSON, YAML, XML, XLIFF, PHP, PO and other files for syntax errors?

Various syntax errors in .json, .xml, .po and other resource files can prevent TextUnited from correctly processing such files.
To check if your file is correctly structured and free of errors, you can use one of these free validators:

JSONLint - The JSON Validator:
https://jsonlint.com/

XML validator:
https://www.w3schools.com/xml/xml_validator.asp

YAML Lint - Validator for .yml files:
http://www.yamllint.com/

PHP Code checker:
https://phpcodechecker.com/

XLIFF 2 Validation:
http://okapi-lynx.appspot.com/validation

RESX:
Microsoft Visual Studio
(Visual Studio offers resource designers that validate the files automatically)