Two sides of the same conversion. YAML → JSON parses a YAML document into JSON; JSON → YAML does the reverse, serializing JSON into readable YAML. Since YAML is a superset of JSON, the two formats are close cousins — and these tools move you between them, both running 100% locally.
Use YAML → JSON when
- You have a YAML config (CI pipelines, Kubernetes, docker-compose) and need it as JSON.
- An API or tool expects JSON but your source is YAML.
- You want to inspect or process a YAML document with JSON tooling.
Use JSON → YAML when
- You have JSON that should become a hand-editable YAML config.
- You're writing or updating a YAML file and starting from JSON data.
- You want cleaner, less-bracketed output for humans to read and tweak.
Side by side
| YAML → JSON | JSON → YAML | |
|---|---|---|
| Direction | YAML → JSON | JSON → YAML |
| Input | YAML | JSON |
| Output | JSON | YAML |
| Handles nesting & lists? | Yes | Yes |
| Comments | Dropped (JSON can't hold them) | Not generated |
| Runs 100% locally | Yes | Yes |
under the hood
One honest caveat: YAML comments and some YAML-specific features (anchors, tags) don't survive into JSON, so a round trip may simplify those. Plain data — strings, numbers, booleans, lists, objects — round-trips cleanly.
bottom line
Use YAML → JSON when you're consuming a config; use JSON → YAML when you're writing one. They're mirrors — and because YAML is a superset of JSON, the crossing is usually lossless for plain data.