YAML to JSON Converter FAQs

Q: Can I convert a YAML file with multiple documents?

Yes, a YAML file with several documents separated by --- lines converts to a JSON array with one item per document, in the original order. This layout is common in Kubernetes manifests that bundle several resources. Empty documents, such as a trailing --- at the end of the file, are skipped, and a single --- at the top of a one-document file is ignored.

Q: How do I convert an OpenAPI or Kubernetes YAML file to JSON?

To convert an OpenAPI (Swagger) or Kubernetes YAML file to JSON, open the .yaml file or paste its contents, and the converter outputs the same keys, nesting and values as JSON. The OpenAPI Specification allows the same document in either YAML or JSON, so the result works with tools that only accept openapi.json, and $ref pointers stay as plain strings. A multi-resource Kubernetes file becomes a JSON array of manifests; kubectl expects one object, so place that array in the items field of a List object (apiVersion: v1, kind: List) before applying it.

Q: Why does my YAML to JSON conversion fail or change values?

YAML to JSON errors usually come from indentation: YAML forbids tabs for indentation and child keys must line up consistently, and the error box shows the line and column of the problem. Duplicate keys in one mapping are rejected too. Watch for type changes: unquoted 1.10 becomes the number 1.1, 010 becomes 10, and integers above 9007199254740991 (2^53 - 1) lose precision, so quote version numbers and long IDs.

Question 1

What is the difference between .yaml and .yml files?

Accepted Answer

The .yaml and .yml extensions are the same format: both files contain YAML and parsers read them identically. The official YAML FAQ recommends .yaml when possible, while .yml stays common in Docker Compose files and GitHub Actions workflows. This converter opens both (plus .txt) with Open YAML File, and the JSON output is the same either way.

Question 2

Is YAML a superset of JSON?

Accepted Answer

YAML 1.2 was designed as a superset of JSON, so practically any valid JSON document is also valid YAML and can be pasted into this converter unchanged. The reverse is not true: YAML adds comments, anchors, block strings and unquoted keys, which have no JSON equivalent. The parser follows the YAML 1.2 core schema, so unquoted yes, no, on and off stay strings instead of becoming booleans as they did in YAML 1.1.

Question 3

What happens to YAML comments, anchors and aliases in JSON?

Accepted Answer

YAML comments are dropped during conversion because JSON has no comment syntax, so keep the original YAML if those notes matter. Anchors (&name) and aliases (*name) are expanded: every alias is replaced with a full copy of the anchored value. Merge keys (<<: *base or <<: [*a, *b]) are applied too, so the anchored keys are copied into the mapping and any key written next to << overrides the merged value.

Question 4

Can I convert a YAML file with multiple documents?

Accepted Answer

Yes, a YAML file with several documents separated by --- lines converts to a JSON array with one item per document, in the original order. This layout is common in Kubernetes manifests that bundle several resources. Empty documents, such as a trailing --- at the end of the file, are skipped, and a single --- at the top of a one-document file is ignored.

Question 5

How do I convert an OpenAPI or Kubernetes YAML file to JSON?

Accepted Answer

To convert an OpenAPI (Swagger) or Kubernetes YAML file to JSON, open the .yaml file or paste its contents, and the converter outputs the same keys, nesting and values as JSON. The OpenAPI Specification allows the same document in either YAML or JSON, so the result works with tools that only accept openapi.json, and $ref pointers stay as plain strings. A multi-resource Kubernetes file becomes a JSON array of manifests; kubectl expects one object, so place that array in the items field of a List object (apiVersion: v1, kind: List) before applying it.

Question 6

Why does my YAML to JSON conversion fail or change values?

Accepted Answer

YAML to JSON errors usually come from indentation: YAML forbids tabs for indentation and child keys must line up consistently, and the error box shows the line and column of the problem. Duplicate keys in one mapping are rejected too. Watch for type changes: unquoted 1.10 becomes the number 1.1, 010 becomes 10, and integers above 9007199254740991 (2^53 - 1) lose precision, so quote version numbers and long IDs.

YAML to JSON Converter

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