What Are YAML and JSON?
YAML and JSON are the two most common configuration formats: JSON is strict and ubiquitous in APIs, while YAML is favored for human-edited config (CI pipelines, Kubernetes, Docker Compose). Rewriting one as the other by hand is tedious and easy to get wrong with indentation. This free YAML ⇄ JSON converter translates between them instantly in your browser, preserving types and structure.
YAML (YAML Ain't Markup Language) and JSON are both human-readable data serialization formats, but they serve different ergonomic niches. YAML uses indentation for structure — no braces or brackets — and supports comments, making it popular for configuration files (Kubernetes, GitHub Actions, Docker Compose, Ansible). JSON uses explicit delimiters and is the native format of web APIs, browser storage and JavaScript. Being able to convert instantly between them is essential when moving between infrastructure config and application code.
How to convert
- Pick a direction: JSON → YAML or YAML → JSON.
- Paste your document — it converts instantly (errors are shown clearly).
- Copy the result into your config or code.
Use Cases
- Converting a YAML configuration file (e.g., a GitHub Actions workflow) to JSON for use in a JavaScript application or API payload.
- Converting a JSON API response to YAML for a cleaner, comment-friendly configuration file.
- Validating YAML syntax — if the converter parses it successfully, the syntax is valid.
- Learning the structural equivalences between YAML and JSON, for example how YAML sequences become JSON arrays.
How YAML-JSON Conversion Works
YAML to JSON: the tool uses the js-yaml library (loaded lazily on first use to keep the initial page load small) to parse the YAML string into a JavaScript object, then JSON.stringify() with two-space indentation serialises it to formatted JSON. The intermediate JavaScript object means all YAML data types — strings, numbers, booleans, nulls, arrays, objects — are mapped to their JSON counterparts.
JSON to YAML: the tool parses the JSON with JSON.parse() and then serialises the resulting object with js-yaml's dump() function. YAML anchors and tags are not preserved in round-tripping because JSON has no equivalent concept.
Why use this tool
- Both directions, with types and nesting preserved.
- Clear error messages for invalid input.
- Runs in your browser — private and free.
Privacy
Conversion runs entirely in your browser using a client-side JavaScript library. Your YAML and JSON data are never sent to our servers.