YAML Formatter
Paste or upload YAML to instantly format, validate or convert it. Everything runs in your browser — your data never leaves your device.
Read the guide: How to format YAMLInput
Formatted YAML
Your YAML is processed to provide formatting and validation. YAML contents are not included in analytics.
How the YAML Formatter works
- Your YAML is parsed using the yaml npm package (YAML 1.2), which validates the document and preserves comments, anchors and aliases.
- For formatting, the parsed document is re-serialised with your chosen indentation (2 spaces or 4 spaces).
- For JSON conversion, the parsed document is converted to a JavaScript object and then to JSON.
- If parsing fails, the error is shown with the line and column where the problem was found.
See also: JSON Validator, JSON Formatter, JSON Minifier and XML Formatter.
Examples
Configuration file
name: SolveWithTools version: 1 features: - JSON tools - XML tools - YAML tools active: true
Nested mapping
server: port: 8080 host: localhost database: host: db.example.com port: 5432
Useful tips
- Use Validate first on broken YAML to find the error before formatting.
- Choose 2 spaces or 4 spaces for formatting — the data stays the same.
- Upload a .yaml or .yml file to format it instantly without pasting.
- Use Convert to JSON to turn YAML configuration into JSON for APIs and tooling.
Frequently asked questions
What is a YAML Formatter?+
A YAML Formatter takes YAML text and applies consistent indentation and formatting to make it easier to read. It parses the YAML to confirm it is valid, then re-serialises it with your chosen indentation (2 spaces or 4 spaces).
How do I format YAML?+
Paste your YAML into the editor or upload a .yaml or .yml file, then click Format YAML. The tool validates the YAML first and, if valid, produces neatly indented output you can copy or download.
How do I beautify YAML?+
Formatting and beautifying YAML are the same thing. Click Format YAML to apply consistent indentation that makes the structure easier to read. You can choose 2 spaces or 4 spaces for indentation.
Why is YAML indentation important?+
Unlike JSON or XML, YAML uses indentation as structure. Incorrect indentation does not just make YAML hard to read — it can change the meaning of the document or make it invalid. Consistent indentation makes the structure unambiguous.
Can I format a YAML file?+
Yes. Click Upload YAML File and choose a .yaml or .yml file. The file is loaded as text into the editor and you can format, validate or convert it instantly. The maximum file size is 5 MB.
What is the difference between YAML and JSON?+
YAML is generally more human-readable and uses indentation for structure. JSON uses braces and brackets. YAML supports comments, anchors, aliases, multi-document files and block scalars — features that standard JSON does not directly represent. YAML is a superset of JSON.
Can YAML be converted to JSON?+
Yes. Click Convert to JSON to parse the YAML and display the equivalent JSON. Comments and anchors are not preserved in JSON, and multi-document YAML becomes a JSON array. The tool warns you when these features are present.
Does formatting YAML change the data?+
No. A proper formatter preserves the YAML data — mappings, sequences, comments, anchors, aliases, block scalars and multi-document separators are all kept. Only the presentation whitespace (indentation) is normalised.
Why does YAML give an indentation error?+
YAML structure depends on indentation. An indentation error usually means items at the same level have different indentation, or a nested item is indented less than its parent. Use spaces consistently — never tabs — and make sure each nesting level adds the same number of spaces.
Can YAML use tabs?+
No. YAML does not allow tabs for indentation. Tabs can cause parsing problems because YAML uses indentation as structure. Always use spaces for indentation — usually 2 spaces per level.
What is the difference between .yaml and .yml?+
There is no functional difference. Both .yaml and .yml are valid file extensions for YAML files. The .yaml extension is the official one recommended by the YAML specification; .yml is a shorter variant that is widely used, especially on systems with file extension length limits.
Is my YAML stored when I use the formatter?+
No. Your YAML is processed entirely in your browser and is never uploaded or stored. We do not include your YAML content in analytics.
Related guides
How to format and validate JSON
JSON is the lingua franca of the modern web, but a single stray comma can break an entire API response. This guide shows you how to format and validate JSON quickly, what the most common errors look like, and how to fix them — all using a free tool that runs entirely in your browser.
How to convert JSON to CSV
JSON is great for APIs, but spreadsheets still rule for analysis. This guide explains how to turn JSON into a clean CSV file, how nested values are handled, and the common pitfalls to avoid — all using a free tool that runs entirely in your browser.
How to validate JSON
A single stray comma can break an entire API response. This guide explains what JSON validation is, the most common syntax errors and how to fix them — all using a free tool that runs entirely in your browser.
How to minify JSON
Minified JSON is smaller, faster to transfer and just as valid as the formatted original. This guide explains what minification does, how it differs from compression, and why your data stays exactly the same — all using a free tool that runs entirely in your browser.
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XML Formatter
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