What is a YAML file?
YAML — human-readable configuration
Use the format YAML
A concrete example
Prepare a JSON from a YAML file for a tool that expects JSON.
Useful checks
Comments, anchors, and implicit types do not all have an equivalent. Check the meaning of values after conversion.
Choose a conversion
Keep the original and open the result in the software or on the device that will need to use it.
Your questions about this format
Why does my JSON change structure when converted to CSV?
CSV represents a table of rows and columns. JSON can contain objects and nested lists that do not transpose directly. Convert a copy, check how the fields are represented, and keep the JSON if your usage requires retaining its entire structure.
How can one avoid losing the leading zeros in identifiers?
When opening the CSV in a spreadsheet, import the identifier columns as text. Automatic opening can turn 00123 into 123. Also check the dates and decimal separators before re-saving.
Can I convert a file containing secrets?
Remove passwords, API keys, and other secrets before sending a sample to the service or support. File processing is done online. For data that must not leave your device, use a suitable local tool.
Why aren't all outputs offered?
Formats are not interchangeable in all cases. ConvertLab displays the conversions from its catalog; renaming an extension does not change the content. Specialized outputs like certain XML exports or spreadsheets are identified as NoLimit.
What is it?
YAML is a configuration format designed to be read and written by humans. No braces, no tags: structure is conveyed through indentation, much like a bulleted list.
It supports comments, which makes it the format of choice for configuration files — an area where JSON, which forbids them, is downright frustrating to work with.
History & origin
YAML appeared in 2001, with the explicit goal of being more readable than XML and more flexible than existing configuration formats.
It has since become a fixture of modern development tooling: continuous integration, container orchestration, automated deployment. Any engineer today writes it on a daily basis.
Why it is useful
Highly readable and concise, it supports comments and handles nested structures with elegance.
It is technically a superset of JSON: any valid JSON file is also valid YAML.
Limits & drawbacks
Indentation is meaningful, and tabs are forbidden: a single misplaced or extra space can change a file's meaning or render it invalid.
Its automatic type conversions are a well-known trap: in older versions, the value NO — the country code for Norway — was interpreted as the boolean "false". This kind of surprise has earned the format a reputation for ambiguity.
Practical tips
YAML is ideal for hand-written configuration. For machine-to-machine data exchange, convert it to JSON: stricter, more predictable, and free of type ambiguity.
Always quote values that could be misinterpreted: yes, no, on, off, and anything that looks like a number without actually being one.
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