YAML Tools
Validate, format, and convert YAML, including JSON round-trips. Comments are usually dropped on re-serialize.
8 tools · 100% browser-based · No uploads · No signup
About these YAML tools
YAML tools validate, format, convert to and from JSON, diff, lint duplicate keys, sort keys, and flatten to .env style. YAML is the language of Kubernetes, Ansible, and GitHub Actions, and it is easy to break with tabs, implicit typing, and duplicate keys.
Norway problem (NO becoming boolean false), unquoted colons, and multiline strings are the usual footguns. Prefer JSON for APIs; use YAML when humans edit nested config and you understand the spec version your runner uses.
Tools in this category
YAML Validator
Validate YAML syntax with clear line-and-column error messages.
YAML Formatter
Format and beautify YAML with the indentation you prefer.
YAML to JSON
YAML is not JSON with comments. `NO` is false, `on` is true, and Norway's country code will disappear into a boolean if you don't quote it.
JSON to YAML
Convert JSON into tidy YAML, with control over indentation.
YAML Diff
Compare two YAML files side by side with structural change highlighting.
YAML Linter
Catch duplicate keys, indentation problems, and trailing spaces in YAML.
YAML Key Sorter
Sort YAML keys alphabetically, with an option to recurse into nested maps.
YAML to ENV
Flatten YAML into .env format, with custom separators for nested keys.
How these tools run in your browser
Parsing uses a JavaScript YAML library in the browser. JSON conversion is a data-model round trip, so comments are dropped. Diff can be structural. .env flattening joins nested keys with a separator you choose. Linter rules are practical, not a full YAML 1.1 vs 1.2 certification.
Common Use Cases
- Find the indent error Kubernetes refuses to apply
- Convert a Helm values snippet to JSON for a script
- Diff two manifests without caring about key order (or sort first)
- Export nested keys to ENV for local docker compose
- Catch duplicate keys that parsers silently overwrite
Common Mistakes
Frequently Asked Questions
YAML 1.1 implicitly types some words as booleans. Quote "NO" or use a 1.2 parser. The linter tries to warn on this class of issue.
Most format paths re-serialize the data model and drop comments. Keep a copy if comments matter.
Processing is local. Still prefer sealed-secrets or a vault rather than pasting production values into any web page.