JSONFormatter.org - Online JSON Formatter and JSON Validator will format JSON data, and helps to validate, convert JSON to XML, JSON to CSV. Save and Share JSON
CodeBeautify - Online Tools like Beautifiers, Editors, Viewers, Minifier, Validators, Converters for Developers: XML, JSON, CSS, JavaScript, Java, C#, MXML, SQL, CSV, Excel
JSONLint - JSON Lint is a web based validator and reformatter for JSON, a lightweight data-interchange format.
WTOOLS.io - Free Online Web Tools. Kit of tools such as generators, minifiers, formatters, checkers, converters, seo and much more
FreeFormatter - Freeformatter is a platform that contains free online tools for developers, including formatters (json, html, xml, sql, etc.), minifiers (css, javascript), compactors, validators, and much more.
JSON Editor Online - View, edit and format JSON online