Mello
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JSON ↔ YAML Converter

Switch between JSON and YAML — useful for Kubernetes, CI configs, and API specs.

Runs in your browserNo account requiredNo uploadFree
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About JSON ↔ YAML Converter

JSON ↔ YAML Converter rewrites data from one syntax into the other. JSON and YAML describe the same underlying data model — objects, arrays, strings, numbers, booleans, and null — so the conversion is about syntax, not meaning. JSON is what most APIs and JavaScript code speak; YAML is the format of choice for configuration: Kubernetes manifests, GitHub Actions and other CI pipelines, Docker Compose files, and OpenAPI specs.

Paste a document in either format and the converter produces the other. A JSON object like {"name":"app","ports":[80,443]} becomes the indented YAML 'name: app' followed by a 'ports:' list with '- 80' and '- 443' beneath it. Paste that YAML back and you get compact JSON. Nesting, ordering, and value types are preserved in both directions.

YAML's richer syntax is handled: anchors and aliases are resolved, multi-line block scalars are read correctly, and the two-space indentation in the output matches what nearly every tool expects. One thing cannot survive a full round trip — comments. YAML allows them and JSON has no comment syntax, so a JSON-and-back conversion drops them.

Conversion happens locally in your browser. Configuration files routinely hold hostnames, environment names, and other internal details, and none of that is uploaded or stored here.

Frequently asked questions

Yes — anchors and aliases are resolved into their full values during conversion.

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