yq -p=json: Read JSON, Output YAML

yq -p=json tells yq the input is JSON; by default it then prints YAML, converting JSON to YAML.

The reverse of YAML-to-JSON: take a JSON config or API response and turn it into readable YAML, or just query it with yq path expressions.

What it does

yq -p=json (or --input-format=json) parses the input as JSON. Since the default output format is YAML, yq -p=json '.' file.json converts JSON to YAML. Pair -p=json with -o=json to query JSON and keep JSON output.

Common usage

Terminal

yq -p=json '.' config.json                 # JSON to YAML
yq -p=json '.image.tag' config.json        # query JSON with yq
yq -p=json -o=json '.spec' config.json     # JSON in, JSON out

Input options

Flag	What it does
-p=json / --input-format=json	Parse input as JSON
-p=yaml	Parse input as YAML (the default)
-p=props / -p=csv / -p=tsv	Parse other input formats
-p=json -o=yaml	Convert JSON to YAML (output default)
-p=json -o=json	Query JSON, keep JSON output

In CI

When an API returns JSON but your tooling wants YAML, curl ... | yq -p=json '.' > config.yaml does the conversion inline. Since JSON is a subset of YAML, yq can often read JSON even without -p=json, but setting it is the reliable choice.

Common errors in CI

"Error: bad file ... could not find expected" on a JSON file usually means you forgot -p=json on input that uses tabs or other JSON-only formatting YAML rejects. Getting YAML when you wanted JSON means you set -p=json but not -o=json. On Python yq the model is inverted (JSON-first, jq-based), so the -p/-o flags do not exist there.