What it is
The JSON & YAML Toolbox is a set of free tools to format, validate, minify, convert and compare JSON and YAML. It exists because the usual online formatters either stop at the first error with a cryptic message, round large numbers, drop YAML comments, or send your text to a server. These tools report every problem with its position, keep your data exactly as written, and never upload anything.
How it works
Everything is static HTML and JavaScript. JSON is handled by a purpose-built diagnostic parser that keeps number text verbatim and collects all errors in one pass. YAML is handled by the open-source yaml library (YAML 1.2), bundled with the page. Differences are computed with the Myers diff algorithm and a structural comparison of the parsed data. There is no application server, database or account.
Who maintains it
The toolbox is built and maintained by an independent developer and kept free by unobtrusive ads. Found a bug, a confusing error message or a file that is not handled well? Please use the contact page; sample input that reproduces the problem helps a lot.