Messy input
name: app
version: 1.0
services:
- web
- db
env:
DEBUG: trueAbout the YAML Formatter playground
The YAML Formatter cleans up YAML documents by normalizing indentation, spacing, and list and map layout so the structure becomes clear and consistent. It helps surface the indentation mistakes that commonly break YAML parsing, and presents nested mappings and sequences in a tidy, predictable form. All processing runs in your browser, so configuration files containing hostnames, secrets, or environment data are never uploaded.
YAML (YAML Ain't Markup Language) is a human-friendly data serialization format widely used for configuration in tools like Docker Compose, Kubernetes, GitHub Actions, and CI pipelines. It uses indentation rather than braces to express nested maps and lists, which makes it readable but sensitive to whitespace. Consistent formatting matters because a single misaligned line can change meaning or cause a parse error, so a formatter helps keep configs valid and easy to review.
HostedYAML Formatter runtime
mainentry file
single fileworkspace
stdinprogram input
How it works
1
Write
The main file is the entry point for each run.
2
Give it input
Use the Input panel to pipe standard input to your program when it needs data.
3
Run
Run sends your code to a fresh hosted runtime and streams the result into the output panel.
4
Keep or share
Your draft stays in this browser, and Share creates a separate snapshot link.
External resources
- yaml.org— Official website
Formatted output
name: app
version: 1.0
services:
- web
- db
env:
DEBUG: trueNested config
server:
host: localhost
port: 8080
options:
- keepalive
- gzipList of maps formatted
users:
- name: Ada
role: admin
- name: Bob
role: editorMultiline strings formatted
description: |
Line one of the text.
Line two of the text.
summary: >
This folds onto
a single line.Multi-document formatted
---
kind: Service
name: web
---
kind: Deployment
name: web
replicas: 3Anchors messy input
defaults: &defaults
retries: 3
timeout: 30
prod:
<<: *defaults
timeout: 60Anchors formatted output
defaults: &defaults
retries: 3
timeout: 30
prod:
<<: *defaults
timeout: 60Flow style formatted
matrix:
node: [16, 18, 20]
os: [linux, macos]
point: { x: 1, y: 2 }How it works
The editor uses Monaco, the engine behind VS Code, with language-aware editing tools and familiar keyboard controls.
What it does
Paste a YAML document and it normalizes indentation, spacing and layout.
Nested mappings and sequences are presented in a tidy, predictable form.
List and map structure is made consistent throughout the file.
Formatting behavior
Surfaces the indentation mistakes that commonly break YAML parsing.
Since YAML is whitespace-sensitive, consistent alignment keeps meaning intact.
Ideal for Docker Compose, Kubernetes, GitHub Actions and CI configs.
Privacy
All processing runs in your browser; config files are never uploaded.
Hostnames, secrets and environment data stay on your machine.
Tips
Copy the cleaned YAML back into your config repo.
Use it to keep configs valid and easy to review.
Every shortcut, searchable:
Editing
Undo
Ctrl+Z
Redo
Ctrl+⇧+Z
Select next occurrence
Ctrl+D
Delete line
Ctrl+⇧+K
Move line up / down
Alt+↑ / ↓
Copy line up / down
Alt+⇧+↑ / ↓
Toggle comment
Ctrl+/
Indent line
Ctrl+]
Outdent line
Ctrl+[
Navigation
Find
Ctrl+F
Find & replace
Ctrl+H
Go to line
Ctrl+G
Go to symbol
Ctrl+⇧+O
Selection
Select all
Ctrl+A
Select line
Ctrl+L
Select all occurrences
Ctrl+⇧+L
Shortcuts follow your OS — ⌘ becomes Ctrl on Windows and Linux.
It normalizes indentation, spacing, and list and map layout in YAML, producing a tidy document and helping reveal whitespace mistakes that break parsing.
No. Formatting happens entirely in your browser, so config files with secrets or environment data never leave your device.
Yes, it is completely free with no sign-up and no usage limits.
Yes. You can set the number of spaces per level so the output matches the convention of your config files.
YAML uses indentation, not braces, to express nesting, and it does not allow tabs for indentation. A single misaligned space can change structure or cause an error, which is why consistent formatting helps.
Input
Output
Output
Start typing to auto-process