YAML ↔ JSON Converter
Convert configuration files instantly with smart detection.
YAML Input
Output
Switching between YAML configs (Kubernetes, Docker Compose, GitHub Actions) and JSON APIs? Paste either format and get instant, validated conversion to the other — with proper handling of comments, anchors, and multi-document files.
Last Updated: April 10, 2025Privacy: 100% Local Browser Processing
What is the Yaml Json Converter?
The YAML ↔ JSON Converter translates data between YAML (YAML Ain't Markup Language) and JSON (JavaScript Object Notation). YAML is the preferred format for configuration files (Kubernetes manifests, Docker Compose, CI/CD pipelines), while JSON is the standard for API communication. This tool handles the conversion in both directions with full support for complex nesting, arrays, multi-line strings, and YAML-specific features like comments and anchors.
Technical Deep Dive
YAML and JSON are both data serialization formats, but they have fundamental differences. JSON is a strict subset of JavaScript with only six data types (string, number, boolean, null, array, object). YAML is a superset of JSON that adds comments (#), multi-line strings (| and >), anchors and aliases (&anchor/*alias for data reuse), and type inference (unquoted strings, dates, booleans). When converting YAML to JSON, the tool must resolve anchors/aliases into their referenced values, discard comments (since JSON does not support them), and convert YAML-specific types into their closest JSON equivalents. The reverse conversion (JSON to YAML) produces clean, human-readable YAML with proper indentation. This tool uses the 'yaml' npm package, a high-performance YAML 1.2 parser that handles all standard YAML features including multi-document files (separated by ---). The parser builds an AST (Abstract Syntax Tree) of the YAML document, which is then serialized to JSON or vice versa.
Real-World Use Cases
- Kubernetes development — convert between YAML manifests (the standard format for kubectl) and JSON (used by the Kubernetes API and some tooling like kustomize).
- CI/CD pipeline debugging — convert GitHub Actions, GitLab CI, or CircleCI YAML configs to JSON to validate their structure programmatically.
- API payload preparation — convert YAML-formatted test data into JSON for use in API requests (Postman, curl, fetch).
- Documentation — convert between formats for inclusion in documentation that requires a specific format.
How to Use
- 1Paste your YAML or JSON code into the left editor.
- 2The tool auto-detects the format and converts it instantly.
- 3Use the 'Format' button to beautify the output.
- 4Copy the result with one click or download it as a file.
Pro Tips & Best Practices
- YAML comments are lost during conversion to JSON because JSON has no comment syntax. Copy your comments separately if you need to preserve them.
- Be careful with YAML's implicit type conversion: unquoted 'yes', 'no', 'true', 'false' become booleans, and values like '1.0' become floats. Quote strings to prevent unexpected type changes.
- When pasting multi-document YAML (separated by ---), each document is converted independently. The JSON output will be an array of documents.
- Use this tool to validate YAML syntax — if the conversion succeeds, your YAML is syntactically correct.