Everything happens locally in your browser - your JSON is never sent to any server.
What does JSON stand for?
JSON stands for JavaScript Object Notation. Despite the name, it's a completely language-independent text format - any programming language with a JSON library, which today means practically all of them, can read and write it.
When and by whom was JSON invented?
Douglas Crockford, together with Chip Morningstar, specified JSON in the early 2000s and sent the first JSON message in April 2001, the same year the JSON.org website launched. It started as a lightweight alternative to XML for JavaScript, and was later formally standardized as RFC 4627 (2006), ECMA-404 (2013), and today's current standard, RFC 8259 (2017).
Where is JSON used?
Almost everywhere data moves between systems: it's the default format for most web APIs and REST services, config files such as package.json for npm, browser localStorage and sessionStorage, NoSQL databases like MongoDB, mobile app data exchange, and log files. If two systems trade structured data over the internet today, there's a good chance it's JSON.
What are the most common JSON mistakes?
The usual culprits: a trailing comma after the last item in an object or array, single quotes instead of double quotes around strings and keys, missing quotes around keys entirely, comments (JSON does not allow them at all), and unescaped special characters inside strings, such as a literal backslash or line break. The Format button above catches all of these instantly.