YAML to JSON

Most configuration is written in YAML and most tooling consumes JSON, so this conversion happens constantly — usually when you want to feed a config file into something that only speaks JSON, or when you need to check what a YAML document actually parses to.

That second case is the more useful one, because YAML has a reputation for surprising people. Indentation defines structure, tabs are forbidden entirely, and a value that looks like text can be read as something else: the word no becomes a boolean in older YAML versions, and a version number like 1.10 becomes the number 1.1. Converting to JSON shows you exactly what the parser saw rather than what you meant.

Errors are reported with a line number, because an indentation mistake several levels deep is otherwise very hard to find. The message is trimmed to one readable line rather than the multi-line excerpt the parser produces by default.

Parsing uses the JSON-compatible schema, which refuses the YAML tags that amount to arbitrary object construction. That distinction matters if you are pasting a document from somewhere you do not control — the permissive schema is a genuine security problem in some YAML libraries, and there is no reason to accept those constructs here.

Everything runs in your browser, so nothing you paste is transmitted.