What is YAML used for?

YAML (YAML Ain't Markup Language) is used primarily for configuration files. Common examples include Docker Compose files, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks, and application config files.

Is YAML a superset of JSON?

Yes, mostly. Valid JSON is valid YAML 1.2, which means you can use JSON syntax in YAML files. However, YAML has additional features (comments, anchors, multi-line strings) that JSON does not support.

Can I lose data converting from YAML to JSON?

YAML features not supported by JSON — like comments, anchors, and custom tags — are dropped during conversion to JSON. All actual data values are preserved.

Why does my YAML have quotes around some values after converting from JSON?

Some values (like strings that look like numbers, booleans, or null) require quotes in YAML to preserve their original type. The converter adds quotes where necessary to ensure the YAML parses to the same values as the original JSON.

JSON ↔ YAML

Bidirectional converter between JSON and YAML formats

Input

Output

Shortcuts: Ctrl+Enter run · Ctrl+L clear · Ctrl+D download

About JSON ↔ YAML

This tool converts between JSON and YAML in both directions. YAML is widely used in configuration files (Docker Compose, Kubernetes, GitHub Actions, Ansible) because it is more human-readable than JSON. Paste JSON to get clean YAML, or paste YAML to get valid JSON — useful when switching between config formats or debugging infrastructure files.

✓Bidirectional conversion — JSON to YAML and YAML to JSON
✓Produces idiomatic YAML with proper indentation and block style
✓Handles anchors, aliases, and multi-line strings in YAML input
✓One-click copy and download of the converted output

JSON and YAML — Same Data, Different Syntax

YAML was designed to be a more human-friendly superset of JSON's data model — every JSON document is technically valid YAML, but YAML adds syntax that makes hand-written configuration files much easier to read and write. Converting between the two is mostly mechanical, but a few details trip people up.

The same data, two ways

# JSON
{
  "service": "api",
  "replicas": 3,
  "env": ["production"],
  "resources": { "cpu": "500m", "memory": "256Mi" }
}

# Equivalent YAML — block style, no braces or commas
service: api
replicas: 3
env:
  - production
resources:
  cpu: 500m
  memory: 256Mi

YAML's block style removes the visual noise of braces, brackets, and trailing commas — which is exactly why it became the default format for tools like Docker Compose, Kubernetes, GitHub Actions, and Ansible, where humans frequently hand-edit configuration.

Where YAML shows up in everyday development

·Kubernetes manifests and Helm charts — deployments, services, and config maps are written in YAML
·CI/CD pipelines — GitHub Actions workflows, GitLab CI, and CircleCI configs all use YAML
·Docker Compose files — service definitions, networks, and volumes
·Application configuration — many frameworks (Spring Boot, Symfony, Ansible) read YAML config files alongside or instead of JSON

Type ambiguity — the trickiest part of conversion

·YAML's parser tries to infer types from unquoted scalars — `yes`, `no`, `on`, `off`, `true`, `null`, and bare numbers can all be interpreted as non-string types depending on the YAML version and parser
·A JSON string like `"yes"` must be quoted in the YAML output (`"yes"` or `'yes'`) — otherwise some YAML parsers will read it back as the boolean `true`, silently changing its type
·Similarly, a string that looks like a number (`"007"`, `"1.0"`) needs quotes in YAML to avoid being parsed as a numeric type on the way back to JSON

Tip: This is exactly why the converter adds quotes around certain values even though your original JSON didn't have them — it is preserving the type, not being inconsistent. If you round-trip JSON → YAML → JSON, the quoting ensures you get the same types back.

Features that don't survive the round trip

·Comments — YAML supports `#` comments; JSON has no comment syntax, so converting YAML to JSON drops them
·Anchors and aliases (`&name` / `*name`) — YAML's mechanism for reusing blocks of config has no JSON equivalent; converting to JSON expands them into duplicated, fully-resolved data
·Multi-line string styles (`|` literal blocks, `>` folded blocks) — these become plain JSON strings with the line breaks preserved as `\n` characters