Free YAML ↔ JSON Converter

Paste YAML or JSON below, pick a direction, and click Convert. YAML is parsed with the battle-tested js-yaml library and parse errors include line information. Everything runs in your browser; nothing is uploaded.

About this YAML ↔ JSON Converter

YAML and JSON describe the same data model — mappings, sequences, and scalars — with very different syntax. Modern infrastructure lives in YAML (Kubernetes manifests, docker-compose files, GitHub Actions workflows, Helm values), while application code and APIs overwhelmingly speak JSON. Moving between the two is a daily chore: you want to feed a compose file into a script that expects JSON, or inspect an API response as YAML because the braces are hurting your eyes. This converter does both directions in one click, entirely in your browser.

YAML parsing uses js-yaml, the most widely used YAML library in the JavaScript ecosystem, so edge cases behave the way your tooling expects. JSON output is pretty-printed with two-space indentation; YAML output wraps long lines at 100 characters. There is no API call, no upload, and no storage.

YAML → JSON: what to expect

• Comments are dropped. JSON simply has no place for them. If your file relies on comments for documentation, keep the YAML as the source of truth.
• Anchors and aliases are expanded. &defaults / *defaults references are resolved into full copies of the data.
• Types are resolved. Unquoted true, null, and numbers become real JSON booleans, nulls, and numbers. This is where surprises hide: an unquoted version like 3.10 parses as the number 3.1. Quote values that must stay strings.
• Key order is preserved as written, which keeps diffs sane.

JSON → YAML: what to expect

Every valid JSON document is representable in YAML, so this direction never loses data. The converter emits block-style YAML — indented mappings and dash-prefixed sequences — which is what humans expect to read. Strings that could be misread as numbers or booleans are automatically quoted by the emitter, so round-tripping is safe.

Common YAML pitfalls this tool helps you catch

• Tabs for indentation. YAML forbids tab characters in indentation; the parser reports the exact line so you can replace them with spaces.
• Missing space after a colon. port:8080 is one scalar string, not a key-value pair. Convert to JSON and the mistake becomes obvious.
• Inconsistent nesting. A list item indented one space too far silently changes the structure. The JSON view shows you exactly what the parser understood.
• Accidental type coercion. Country code NO, git SHAs made of digits, or octal-looking IDs — converting to JSON reveals what type each value actually parsed as.

If a manifest fails in CI or a cluster rejects it, converting it here is a fast sanity check: a parse error with a line number points at the syntax problem, and clean JSON output confirms the structure is what you intended. For a tour of the usual suspects, see our guide to common YAML errors in Kubernetes and CI.

When to use which format

Use YAML where humans edit files by hand and comments matter: configuration, infrastructure manifests, CI pipelines. Use JSON where machines exchange data: APIs, logs, storage. Both formats express the same structures, so pick per audience — and use this tool at the boundary. For a fuller comparison, read YAML vs JSON: the differences explained.

FAQ: YAML ↔ JSON Converter