JSON ⇄ YAML Converter

How It Works

The converter is two-way: JSON to YAML parses with the built-in JSON.parse and serializes with js-yaml, and YAML to JSON does the reverse. Conversion runs automatically as you type (debounced by a quarter of a second), and a syntax error in either direction shows the parser message on a red line and clears the output.

Why YAML

YAML is the language of configuration files — Kubernetes manifests, GitHub Actions workflows, Ansible playbooks. The block style is far more readable than the equivalent JSON: no braces, no commas, and keys and comments can sit at the top level of the document. Comments are allowed in YAML but have no counterpart in JSON, which is why they never survive a conversion.

Dump Options

The JSON to YAML output uses a 2-space indent, block style for sequences and mappings, no anchors or aliases (the js-yaml default), and strings are only quoted when they have to be — plain text like hello stays unquoted.

Key Order

Key order is preserved when dumping to YAML: js-yaml emits the properties in the order they appear in the source document, which is also the order JSON.parse stores them in the object.

What Is Lossy

Comments are dropped in both directions (JSON cannot carry them and the parser discards YAML ones). Multi-document YAML files separated by --- are not supported — this tool parses a single document, so split a stream and convert each part separately. Duplicate keys in JSON collapse to the last value, as the format requires.

Date-like Strings

YAML 1.1 famously resolved bare values like 2024-01-01 to native date objects. The parser used here follows the modern core schema instead: we verified that date-like strings load as plain strings and are dumped with quotes ('2024-01-01'), so they survive a round trip as text and never silently turn into timestamps.

Frequently Asked Questions