Free Online Tool

YAML ↔ JSON Converter

Convert between YAML and JSON instantly in your browser

No data is sent to any server — everything runs client-side

YAML Input

Paste your YAML here

Input

JSON Output

Converted result

Output

What Is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format that uses indentation to represent structure. Originally designed as a superset of JSON, YAML supports the same data types (strings, numbers, booleans, null, objects, arrays) but adds features like comments, multi-line strings, anchors/aliases, and custom tags.

YAML is the dominant configuration format in the cloud-native ecosystem: Kubernetes manifests, Docker Compose files, GitHub Actions workflows, Ansible playbooks, Helm charts, and CI/CD pipelines all use YAML. Its readability advantage over JSON comes at the cost of whitespace sensitivity — incorrect indentation silently changes the document's structure.

YAML vs JSON: Key Differences

Feature	YAML	JSON
Comments	✓ `# comment`	✗ Not supported
Multi-line strings	✓ `\|` and `>` operators	✗ Escaped `\n` only
Quoting	Optional for most strings	Double quotes required
Anchors & aliases	✓ Reusable data blocks	✗
Readability	High (minimal syntax)	Medium (braces & brackets)
Parsing speed	Slower (complex grammar)	Faster (simpler grammar)

When to Convert

Kubernetes & Docker

Convert K8s manifests or docker-compose.yml to JSON for programmatic manipulation with jq, API submissions, or language SDKs that only accept JSON.

CI/CD Pipelines

GitHub Actions, GitLab CI, and Azure Pipelines use YAML configs. Convert to JSON to debug parsing issues or generate configs programmatically.

API Payloads

Some APIs accept YAML (OpenAPI specs, CloudFormation). Convert between formats to match what your tools or clients expect.

Config Migration

Moving between tools that prefer different formats (e.g., JSON-based tsconfig.json to YAML-based equivalents or vice versa).

Common YAML Pitfalls

The Norway Problem

YAML 1.1 interprets NO, yes, on, off as booleans. Country code NO becomes false. Always quote ambiguous strings.

Tabs vs Spaces

YAML does not allow tabs for indentation — only spaces. Mixing tabs and spaces causes cryptic parsing errors.

Implicit typing

Values like 3.10 become the float 3.1, and 1e3 becomes 1000. Quote version numbers and similar strings.

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XML vs JSON Guide

In-depth format comparison

How to Use the YAML ↔ JSON Converter

Select conversion direction

Choose the "YAML → JSON" tab to convert YAML to JSON, or "JSON → YAML" to convert JSON to YAML.

Paste your content

Paste your YAML or JSON content into the input textarea on the left. You can type directly or paste from the clipboard.

Convert

Click the "Convert to JSON" or "Convert to YAML" button. The output appears instantly on the right.

Copy the result

Use the Copy button to copy the converted output to your clipboard for use in your project.

Frequently Asked Questions

Can YAML represent everything JSON can?▼

Yes — YAML is a superset of JSON, meaning every valid JSON document is also valid YAML 1.2. However, YAML 1.1 (used by many libraries) has quirks like interpreting YES/NO and ON/OFF as booleans that JSON does not.

Why does my YAML fail to parse?▼

The most common cause is incorrect indentation (tabs instead of spaces), colon-without-space issues, or special characters in unquoted strings. Use consistent 2-space indentation and quote strings that contain special characters like : # [] {} or start with numbers.

What happens to YAML comments during conversion?▼

YAML comments (lines starting with #) are not preserved in the JSON output, because JSON has no comment syntax. This is expected behavior — comments are metadata for YAML authors, not part of the data structure.

Does this tool support YAML anchors and aliases?▼

Yes. Our YAML parser resolves anchors (&anchor) and aliases (*anchor) so the output JSON reflects the fully expanded data structure.

Is my data sent to a server?▼

No. All conversion happens entirely in your browser using the js-yaml library. Your data never leaves your device.

My Kubernetes manifest uses multi-line strings with |. Does that work?▼

Yes. YAML block scalars (| for literal, > for folded) are fully supported. The literal block (|) preserves newlines; the folded block (>) converts newlines to spaces. Both are correctly parsed and represented in JSON.