Free · without registration
Check YAML and format readably
Check YAML from configurations for syntax errors and duplicate keys. Get a readable formatted output with comments and anchors – without uploading.
Entry and options
Their results
Finding indentations and double keys
YAML uses indentations for its structure. A tab in the wrong place, an incomplete mapping entry, or a duplicate key can make the configuration unusable. The validator reports parser errors with context. Duplicate keys are not silently replaced by the last value.
Comments, anchors and several documents
Comments are retained in the document model. Anchors and aliases are not inflated to multiple copied data; their references are checked and excessive alias expansion is limited. A stream of several YAML documents is also possible. The output formats with two spaces and can change the original representation of strings or line breaks.
Syntax testing does not replace application testing
The standard evaluation uses YAML 1.2; explicit version directives are taken into account. Whether a key is technically allowed in TYPO3, Kubernetes or a CI configuration is decided by their respective schema. Unknown own tags are displayed as hints. Therefore, check the formatted file in the target application before use.
Open the file locally and take the result
Add up to 500 KB of UTF-8 or open one. yaml or . yml file. After successful testing, you can copy or download the output. Processing in the worker with a time limit prevents problematic inputs from permanently blocking the user interface. Implementation benefits the documented YAML parser.
Example of classification
Two entries with the same base key on one level are reported as errors. “base” in two different language objects is allowed.
Frequent questions
Does the tool fully check my TYPO3 configuration?
No. It checks YAML syntax and structural rules, but not a version-dependent TYPO3 scheme.
Will comments be received?
Yes, in the parser document model. The exact formatting may change at output.
Is YAML stored on the server?
No. File import, checking and formatting run locally in the browser.