Convert YAML to JSON

When YAML needs to become JSON

YAML is the language of configuration: Kubernetes, Docker Compose, GitHub Actions, OpenAPI specs and countless app settings. It is pleasant to write, but indentation mistakes are easy to make and many tools, validators and APIs only accept JSON.

This converter parses YAML with the yaml library using the YAML 1.2 specification, resolves anchors and aliases, and writes indented JSON. If the file contains several documents separated by ---, you get a JSON array with one element per document.

YAML vs JSON at a glance

How to convert YAML to JSON

1. 1

   Step 1: Select a .yaml or .yml file

   Drop the config or spec file onto the converter.

2. 2

   Step 2: Keep JSON as the target

   JSON is preselected.

3. 3

   Step 3: Convert

   The YAML is parsed; syntax errors are reported with a message instead of producing broken output.

4. 4

   Step 4: Download the JSON

   Use it with validators, APIs or JavaScript code.

YAML features supported

Common YAML to JSON conversions

• OpenAPI and Swagger. Some tools only import the JSON form of an API spec.

• Kubernetes debugging. Inspect manifests with JSON tools such as jq.

• Schema validation. JSON Schema validators usually expect JSON input.

• App configuration. Load settings in environments without a YAML parser.

What is lost in translation

JSON has no comments, so YAML comments disappear. Anchors and aliases are expanded, which can make the JSON longer when the YAML reused large blocks. Key order is preserved.

Custom tags such as !Ref or !GetAtt, used by AWS CloudFormation, are not standard YAML and may cause warnings or be converted as plain values. Convert CloudFormation templates with AWS tooling when those tags matter.

YAML 1.2 versus 1.1

Older YAML parsers followed YAML 1.1, where yes, no, on and off meant true or false and values like 0755 were octal numbers. This converter follows YAML 1.2, where those words stay strings unless written as true or false. That is safer, but it may differ from what an older tool produced.

Dates written without quotes stay as strings in the JSON, which avoids time zone surprises.

• country: NO stays "NO" (the Norway problem avoided).
• enabled: true becomes true.
• mode: 0755 stays a number in YAML 1.2 as 755.

Tips for YAML to JSON

• Use spaces, never tabs, for YAML indentation.
• Quote strings that contain colons followed by spaces.
• Check multi-document output: it is an array even if you expected one object.
• Convert back with JSON to YAML after editing, if needed.

YAML to JSON questions