YAML to JSON Converter

YAML anchors (&name) and aliases (*name) are a powerful DRY mechanism that lets you define a value once and reference it multiple times. During conversion to JSON, our tool automatically expands all anchors and aliases — every alias is replaced with the full referenced value. This is necessary because JSON has no equivalent construct. For example, if you define defaults: &defaults with adapter: postgres and port: 5432, then later use <<: *defaults, the resulting JSON will contain the expanded adapter and port values directly. If you need to preserve anchor information for documentation purposes, consider adding comments in the output JSON.

YAML comments (lines starting with #) are stripped during conversion because JSON does not support comments natively. This is by design — JSON is a data format, not a documentation format. If you need to preserve descriptive annotations, we recommend one of three approaches: (1) before conversion, convert critical comments to named fields using specialized tools, (2) after conversion, use JSON5 or JSONC parsers that support comments in downstream tooling, or (3) maintain the original YAML as your documentation source and treat JSON as the machine-readable derivative. For Docker Compose files where comments document service purposes, consider adding explicit label or description fields instead.

Yes. Multi-document YAML streams (separated by ---) are fully supported. Our converter offers two handling modes: (1) Array mode wraps all documents as elements of a top-level JSON array, preserving the order and boundaries between documents. This is ideal for Kubernetes multi-resource files or CI pipeline definitions with multiple stages. (2) Sequential mode processes each document one at a time, allowing you to inspect and copy each JSON output individually. For very large multi-document streams, the tool automatically switches to streaming mode to handle memory efficiently without blocking the browser interface.

Absolutely not. The YAML parser runs entirely in your browser using WebAssembly-compiled code. No data, network requests, or telemetry leave your device. You can safely convert files containing database credentials, API keys, private infrastructure definitions, or any sensitive configuration data. The tool works fully offline once the page has loaded — you can disconnect from the internet and continue converting. This local-first architecture is the fundamental security advantage over cloud-based converter services that upload your files to remote servers for processing.

Our converter supports both YAML 1.1 and 1.2 specifications. Version 1.2 is the current standard (released 2009) and resolves several ambiguities from 1.1. Key differences include: booleans (1.1 accepted yes/no/on/off as booleans; 1.2 requires true/false only), octal numbers (1.1 used leading zero; 1.2 uses 0o prefix), and merge key behavior. By default the tool parses input as YAML 1.2, but automatically detects and adapts when 1.1 constructs are encountered, issuing a non-blocking warning. If you are converting legacy Ansible or Puppet files that rely on 1.1 semantics, the tool handles the conversion correctly while flagging potentially ambiguous constructs.