YAML Formatter
Format, validate, and convert YAML to JSON and JSON to YAML. Bidirectional converter with file upload — free and private.
How to Use
Step-by-step guide to get the most from this tool
- 1
Choose direction
Select YAML → JSON or JSON → YAML conversion mode.
- 2
Paste or upload
Enter your data or upload a file. Use Load sample for a quick demo.
- 3
Copy or swap
Copy the formatted output, or swap to convert back to the other format.
Features
What makes this tool stand out
Bidirectional
Convert YAML to JSON and back with one click.
File upload
Load .yaml, .yml, and .json files locally.
Instant validation
Syntax errors shown with parser messages.
Private
100% client-side — configs never uploaded.
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Frequently Asked Questions
Quick answers to common questions
How do I convert YAML to JSON?+
Paste your YAML in the input panel with YAML → JSON mode selected. Valid JSON appears instantly in the output panel. Use Copy output to grab the result.
Can I convert JSON to YAML?+
Yes. Switch to JSON → YAML mode, paste JSON, and get formatted YAML output. Use the Swap button to flip direction with current output.
Is my data uploaded to a server?+
No. All parsing and conversion happens entirely in your browser using the yaml npm package. Your configs never leave your device.
What YAML features are supported?+
Standard YAML 1.2 including arrays, nested objects, booleans, and numbers. Kubernetes and Docker Compose configs are supported.
Can I upload a YAML file?+
Yes. Click Upload file to load .yaml, .yml, or .json files from your computer.
How do I fix YAML syntax errors?+
Invalid YAML shows a detailed error message from the parser. Common issues: incorrect indentation, missing colons, or unquoted special characters.
What indent size should I use?+
JSON output supports 2 or 4 space indent. YAML output uses the same setting. Most projects use 2 spaces.
YAML vs JSON — when to use which?+
YAML is human-readable for config files (Kubernetes, CI/CD). JSON is better for APIs and data interchange. Convert between them as needed.