YAML to JSON Converter
Convert YAML to JSON and JSON to YAML instantly — supports anchors and aliases
What is YAML to JSON Converter?
YAML (YAML Ain't Markup Language) and JSON are both structured data formats, but they serve different audiences. YAML is optimised for human readability and authoring — it uses indentation instead of brackets, allows comments, supports multi-line strings naturally, and is dramatically less verbose than JSON. It is the default format for Docker Compose files, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks, and most CI/CD pipeline configurations. JSON is optimised for machine consumption — it is stricter, faster to parse, and universally supported in every programming language. The need to convert between them is constant: a Kubernetes YAML manifest needs to be sent to an API that expects JSON, a JSON config from a database needs to be converted to YAML for source control, or a developer wants to preview how a YAML file will parse before loading it in code. Our free YAML to JSON Converter handles both directions. Paste YAML and get clean, formatted JSON. Paste JSON and get readable, properly indented YAML. It correctly handles YAML-specific features including multi-document streams, anchor (&) and alias (*) references, and block scalars.
How to Use YAML to JSON Converter
- 1
Paste Your YAML or JSON
Paste your YAML configuration (Docker Compose file, Kubernetes manifest, GitHub Actions workflow) or JSON object into the input area. The tool auto-detects the input format.
- 2
Convert
Click "YAML to JSON" or "JSON to YAML". YAML anchors and aliases are resolved before conversion. The output is formatted — JSON with indentation, YAML with consistent 2-space indentation.
- 3
Copy or Download
Copy the converted output to clipboard, or download it as a .json or .yaml file ready for use in a pipeline, config directory, or API call.
Use Cases
Converting Kubernetes Manifests for API Calls
Kubernetes manifests are written in YAML for human maintainability, but the Kubernetes API accepts JSON. When making direct API calls with curl or Postman to apply a resource, or when working with the raw Kubernetes API in a language that generates JSON, convert your YAML manifest to JSON here to get a valid API request body without manually rewriting the syntax.
Debugging CI/CD Pipeline Configurations
GitHub Actions, GitLab CI, and CircleCI configs are written in YAML. When a pipeline fails with an unexpected structure error, converting the YAML to JSON here provides a different view of the parsed structure — often making it easier to spot missing quotes around version numbers, incorrectly indented steps, or a misplaced anchor reference that caused the YAML parser to produce an unexpected object shape.
Editing YAML Config in Systems That Accept JSON
Some configuration panels, deployment tools, and infrastructure-as-code platforms accept configuration in JSON format but your team maintains configs in YAML for readability. Convert your YAML source to JSON here for the platform import, and reverse-convert any JSON exports back to YAML for storage in version control — keeping the human-readable YAML as the source of truth.
Features
Bidirectional Conversion
Convert YAML → JSON and JSON → YAML in one tool. Both directions produce properly formatted, human-readable output.
Anchor and Alias Resolution
YAML anchors (&name) and aliases (*name) are correctly resolved before conversion, producing valid JSON where all references are fully expanded.
Syntax Validation
Invalid YAML or JSON input is caught with a clear error message indicating where the syntax error is — helping you fix malformed config files before running a deployment.
Multi-Document YAML Support
Handles YAML files containing multiple documents separated by --- (common in Kubernetes manifests) and converts each document separately.
Frequently Asked Questions
YAML (YAML Ain't Markup Language) is a human-friendly data serialisation format that uses indentation and minimal punctuation. Key differences from JSON: YAML allows comments (# comment); YAML uses indentation instead of curly braces and brackets; YAML strings usually don't require quotes; YAML supports anchors, aliases, and multi-document streams; YAML is a superset of JSON (valid JSON is valid YAML). YAML is harder to parse correctly but much more pleasant to write by hand.
YAML anchors (&name) mark a value so it can be referenced multiple times, and aliases (*name) reference a previously defined anchor — essentially a DRY (Don't Repeat Yourself) mechanism within a YAML file. For example: defaults: &defaults timeout: 30 production: <<: *defaults host: prod.example.com. The << merge key expands the anchored defaults into the production object. When converting to JSON, all anchors are resolved and aliases expanded so the JSON contains the fully expanded values.
Yes — JSON is technically a subset of YAML 1.2. All valid JSON is valid YAML. YAML's design explicitly chose to be a superset of JSON so that JSON files can be used wherever YAML is expected. However, the reverse is not true — YAML files are typically not valid JSON because they use YAML-specific syntax (comments, unquoted strings, anchors) that JSON parsers do not understand.
Kubernetes and Docker Compose chose YAML because it is significantly more readable and writable by humans compared to JSON. Kubernetes manifests can be very long (deploying a complex application might involve hundreds of lines of config), and YAML's indentation-based structure and support for comments make these files much more maintainable. The Kubernetes API accepts both YAML and JSON — YAML files are converted to JSON internally before being processed.
In YAML, --- marks the start of a new document within the same file. Multi-document YAML files are common in Kubernetes, where a single manifest file might contain a Deployment, a Service, and a ConfigMap all separated by ---. When converting a multi-document YAML file to JSON, each document becomes a separate JSON object. This tool converts each document independently and arrays the results, or you can convert one document at a time by removing the other sections.
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