JSON to YAML

YAML is significantly more readable than JSON for configuration files that humans edit by hand. It removes most of the visual noise — no quotes around keys, no braces, no commas at line ends — and replaces them with indentation. It also supports comments, which JSON famously doesn't, so you can document why a value exists right next to it. This is why nearly every modern infrastructure tool defaults to YAML: Kubernetes manifests, Docker Compose files, GitHub Actions workflows, GitLab CI configs, Ansible playbooks, OpenAPI specs, CircleCI configs, and Helm charts are all YAML. JSON remains better for machine-to-machine API payloads where strictness matters more than readability.

Yes, the conversion is lossless for all standard JSON types. Strings, numbers, booleans, null, arrays, and nested objects all round-trip cleanly — you can convert JSON to YAML and back without losing or changing any data. The only thing that changes is formatting and indentation. One edge case to be aware of: if your JSON has keys that look like YAML special values (the strings 'yes', 'no', 'on', 'off', 'true', 'false', or unquoted numbers), they'll be quoted in the YAML output to avoid type ambiguity. That's correct behavior — YAML 1.1 would otherwise parse those as booleans.

Yes, up to 5MB of JSON, which covers the vast majority of real-world config files and API responses. The parsing happens in your browser using js-yaml and JavaScript's native JSON.parse, both of which handle multi-megabyte payloads in milliseconds on modern hardware. If you're working with truly massive JSON in the multi-GB range — data exports, log dumps — you're better off using a streaming tool like jq on the command line. But for the common cases of a 100KB Kubernetes manifest or a 500KB OpenAPI spec, this handles it instantly.

The output uses 2-space indentation, which is the de-facto standard across Kubernetes, Ansible, Docker Compose, and most other YAML-based tools. Tabs are never used — the YAML spec actually forbids tabs for indentation, and many YAML parsers will throw cryptic errors if they encounter them. If your existing project uses 4-space indentation, you can quickly find-and-replace after pasting in. Keys are always emitted in the same order they appeared in the JSON input, so diffs against an existing YAML file remain readable.