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
JSONLint - JSON Lint is a web based validator and reformatter for JSON, a lightweight data-interchange format.
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
JSON Formatter & Validator - The JSON Formatter was created to help with debugging.
ExtendsClass JSON Formatter - ExtendsClass JSON Formatter is a tool that allows you to beautify, minify, validate, view, and escape JSON code.