YAML ↔ JSON Converter

Free online YAML to JSON converter — convert Kubernetes manifests, Docker Compose configs, and CI/CD pipelines between YAML and JSON formats.

YAML Input

About YAML ↔ JSON Converter

YAML (YAML Ain't Markup Language) and JSON (JavaScript Object Notation) are both data serialization formats used extensively in modern software development. JSON is a subset of JavaScript syntax — strict, minimal, and universally supported. YAML is more expressive, supporting comments, anchors, multi-line strings, and multiple document types in a single file.

JSON is the standard for web APIs and data interchange over the network. Every programming language has built-in or library support for parsing and generating JSON. Its strict syntax eliminates ambiguity but can be tedious for humans to write manually, especially for deeply nested structures without proper tooling.

YAML is the preferred format for configuration files in tools like Docker Compose, Kubernetes, GitHub Actions, Ansible, and CI/CD pipelines. Its indentation-based syntax and support for comments make it more readable for human-authored configuration. However, YAML's complexity (implicit typing, multi-document support) can lead to subtle bugs.

Converting between the two formats is common when bridging different systems. You might need to convert a Kubernetes YAML manifest to JSON for programmatic processing, or convert a JSON API response to YAML for inclusion in documentation or configuration. This tool handles the conversion bidirectionally with proper formatting.

Key differences to remember: YAML supports comments (#), JSON does not. YAML uses indentation for structure, JSON uses braces. YAML has multiple data types (dates, timestamps), JSON has only strings, numbers, booleans, null, objects, and arrays. YAML can define reusable anchors (&) and aliases (*) to avoid duplication.

When working with Kubernetes configurations, understanding the YAML-JSON relationship is essential. Although Kubernetes manifests are typically authored in YAML, the Kubernetes API server accepts JSON internally and converts YAML to JSON before processing. This means any YAML-to-JSON converter is directly useful for debugging Kubernetes resource definitions, verifying syntactic correctness of your configs, and programmatically generating or modifying Kubernetes resources in CI/CD pipelines.

Frequently Asked Questions

Can I convert JSON to YAML and back without losing data?

Yes, for standard data. However, YAML-specific features like comments, anchors, multi-document files, and custom types are lost when converting to JSON. JSON-to-YAML conversion is lossless since JSON represents a subset of YAML's capabilities.

Why does my YAML fail to parse?

Common YAML issues: inconsistent indentation (must use consistent spaces, not tabs), confusion between strings and numbers ('yes' and 'true' are boolean in YAML 1.1), and using tab characters (YAML forbids tabs for indentation).

When should I use YAML vs JSON?

Use YAML for human-authored configuration files (Docker, Kubernetes, CI/CD). Use JSON for machine-to-machine data exchange (APIs, data storage, WebSocket messages). YAML is more readable for humans; JSON is more reliable for machines.

Why does YAML convert 'yes' and 'no' to booleans?

YAML 1.1 treats 'yes', 'no', 'on', 'off', 'true', and 'false' as boolean values unless explicitly quoted. This is a common source of bugs — the string 'yes' becomes the boolean true. Quote values that must remain strings: use 'yes' in quotes. YAML 1.2 removed implicit typing for 'yes' and 'no', but many tools still implement YAML 1.1.

Can YAML represent the same data more compactly than JSON?

Not typically. YAML's indentation-based syntax often requires more lines than JSON for the same data. However, YAML's anchors (&) and aliases (*) can reduce repetition in complex documents by referencing previously defined nodes, which JSON cannot do. For simple flat data, JSON is usually more compact.