Donaldson R F YAML Formatter & Validator
Check that your YAML is valid, find the exact line of any mistake, and tidy it up with consistent indentation.
About this validator
The YAML is parsed with the js-yaml library (YAML 1.2 core schema). If it is invalid you see the error message with its line and column. When it is valid, it is written back out with your chosen indentation; multiple documents separated by --- are supported. Comments are not preserved when re-formatting (they are not part of the data), quoting style may change, and flow-style lists like [a, b] become block lists — so keep your original if the comments matter. Everything runs in your browser; nothing is uploaded.