YAML to JSON Converter

What Is the YAML to JSON Converter?

YAML is a popular human-readable configuration format (used by Docker Compose, GitHub Actions, Kubernetes, and many other tools) that relies on indentation to express structure. This tool converts a common, practical YAML subset -- nested maps, key: value pairs, and block sequences (- item) -- into JSON.

How to Use This Tool

Paste YAML using standard indentation. The equivalent JSON structure appears instantly.

What This Tool Supports

Worked Example

Practical Uses

• Inspecting a Docker Compose or CI config file's structure as JSON
• Converting simple YAML settings for use in a JSON-consuming script
• Learning how YAML's indentation-based structure maps onto JSON

For .ini-style config files instead, see the INI to JSON Converter.

How Values Are Typed

Unlike an INI converter, this tool does interpret scalar values. After trimming, an empty value, a tilde or the word null becomes JSON null. The words true and false become booleans. A value made only of digits, with an optional leading minus sign, becomes an integer. Digits with a single decimal point become a floating-point number. A value wrapped entirely in double or single quotes has the quotes removed and stays a string, which is the way to force text that would otherwise be typed: writing a version like "1.20" in quotes keeps it a string, while an unquoted 1.20 becomes the number 1.2 and loses its trailing zero. Anything else stays a plain string.

Indentation Is the Structure

Nesting is decided entirely by leading spaces. A key with no value on its line opens a child block made of the following lines that are indented deeper. Consistency matters: keep sibling keys at exactly the same indentation. If a line is indented differently from its siblings, it may be skipped or attached to the wrong parent, and the resulting JSON will look wrong even though no error appears. Use spaces rather than tabs, which YAML itself does not allow for indentation.

A Worked Example With a List of Objects

Suppose you write a top-level key called servers with two list entries, each beginning with a dash and each holding a name key and a port key. The converter treats each dash line that contains a colon as the start of a small map, gathers the more deeply indented lines below it as further keys of that same map, and produces a JSON array of two objects. A dash followed by a plain value, such as a tag name, produces an array element that is a scalar. Comment lines beginning with a hash and blank lines are removed before parsing.

Unsupported Features and Error Messages

• Flow style such as curly braces or square-bracket lists, anchors and aliases, multi-line block scalars (the pipe and greater-than indicators), multiple documents separated by three dashes, and complex keys are not supported. Content using them may be misread or rejected, so rewrite it in block style first.
• A non-list line at a mapping level with no colon produces an error message that quotes the offending line, which is the fastest way to find a typo.
• Empty input returns an error, and a key with no value and no indented children becomes null.
• Colons inside values are fine because only the first colon splits the key. Text such as a time or URL is kept in full, but a key that itself contains a colon is split at the first one.

Treat the output as a convenient conversion for simple configuration, not a full YAML validator. For production pipelines with anchors or multi-document files, use a complete YAML library.

Frequently Asked Questions