YAML to JSON Converter Online 2026 - Fast, Secure & Private
Convert YAML to JSON instantly. Transform YAML configuration files to JSON format. 100% client-side privacy. Free online tool.
Key Features
- ✅ Converts complex YAML maps and lists
- ✅ Preserves data types (strings, numbers, booleans)
- ✅ Instant preview and conversion
- ✅ Browser-based, secure processing
How to Use
- Paste your YAML content into the editor
- The tool will automatically validate your YAML syntax
- Click Convert to generate the JSON equivalent
- Copy the resulting JSON for use in your code or APIs
Expert FAQ
- How does it handle YAML anchors (&) and aliases (*), and what about merge keys (<<:)?
Anchors and aliases are fully resolved during parsing — a *ref alias is replaced with a deep copy of whatever its &ref anchor pointed to, so the output JSON has no concept of "this value is referenced elsewhere," it's just expanded inline. Merge keys (<<: *defaults, used heavily in Helm/Kubernetes YAML to compose base configs) are also resolved, merging the referenced mapping's keys into the current one before conversion. - My YAML has a value like "on" or "no" used as a key or value — will it become a boolean in the JSON?
This depends on which YAML version the parser targets. YAML 1.1 (still the de-facto behavior of many tools, including older PyYAML) treats unquoted yes/no/on/off/y/n as booleans — this is "the Norway problem," since the country code "NO" famously becomes the boolean false. YAML 1.2 narrowed this to just true/false. This converter follows YAML 1.1's broader boolean set for compatibility with the widest range of source files, so quote any such value in your source YAML (e.g. "on": true becomes "\"on\": true") if you need it preserved as a literal string. - Are comments in my YAML file preserved anywhere in the JSON output?
No — JSON has no comment syntax at all, so any # comments in the source YAML are necessarily dropped during conversion. There is no way to preserve them in standards-compliant JSON; if you need the comments to survive, keep the YAML file as the source of truth and treat the JSON as a derived, comment-free build artifact. - Is multi-document YAML (separated by ---) supported?
This converter processes the first document in a multi-document stream and stops there. If your file legitimately contains multiple --- separated YAML documents (common in Kubernetes manifests bundling several resources in one file), split it into separate single-document files before converting each one, since JSON itself has no native multi-document concept to map them into.
Technical Details
YAML is a superset of JSON's data model — every valid JSON document is also valid YAML, but YAML adds features with no JSON equivalent: anchors/aliases for reusing a value by reference, merge keys for composing mappings, comments, and a looser, more permissive scalar-typing system. Converting YAML to JSON means resolving all of those YAML-only features down into JSON's simpler model, which is a one-way trip — round-tripping JSON back through YAML to JSON won't reintroduce anchors or comments that existed in some earlier YAML version of the data. Anchors (&name) and aliases (*name) are expanded inline rather than preserved as references, and merge keys (<<: *base, the mechanism Helm charts and Kustomize overlays frequently use to compose configuration) are resolved by merging the referenced mapping's keys before the rest of the document is parsed. Scalar typing follows YAML 1.1 conventions for booleans (yes/no/on/off/y/n in addition to true/false) since that remains the practical default across the YAML tooling ecosystem, despite YAML 1.2 narrowing the boolean set — meaning a bare "no" in your source YAML will convert to the JSON boolean false unless it was quoted. Comments have no JSON representation and are unconditionally dropped; if a YAML config relies on comments for maintainability, the YAML should remain the canonical source and the JSON treated as a generated artifact, not the other way around. Once converted, the JSON Formatter and JSON Validator are useful for reviewing and confirming the output's structure.