YAML formatter/validator · Guide
YAML Formatter Online: Validate and Tidy YAML
A YAML formatter validates your YAML and re-emits it with clean, consistent indentation. Because YAML is whitespace-sensitive, that validation step catches the errors that break pipelines. This guide explains how it works.
Validate first, format second
The formatter parses the YAML before reformatting it, so an indentation slip or a stray tab is reported instead of silently producing wrong structure. Only valid YAML gets reformatted.
It runs in the browser, so config files with internal hostnames or secrets stay on your machine.
Why indentation matters
In YAML, indentation defines nesting. A line indented one space too far changes which block it belongs to. Normalising indentation makes the real structure visible and consistent.
Frequently asked questions
Why does YAML break with tabs?
YAML does not allow tabs for indentation — only spaces. A tab is a common cause of parse errors; replace tabs with spaces and the file usually validates.
Ready to try it?
Open the free browser-based YAML formatter/validator and apply what you just read — no sign-up, runs locally.
Open the YAML formatter/validator tool