YAML Formatter & Validator
Paste messy YAML, get perfectly indented output. Validate syntax, fix indentation errors, and convert to JSON — all client-side with zero data transmitted.
Open YAML FormatterBefore & After
❌ Messy YAML
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-app
labels:
app: my-app
version: "1.0"
spec:
replicas: 3
selector:
matchLabels:
app: my-app✅ Formatted YAML
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-app
labels:
app: my-app
version: "1.0"
spec:
replicas: 3
selector:
matchLabels:
app: my-appFeatures
YAML Beautifier
Fix indentation and formatting with one click. Consistent 2-space indentation throughout.
Syntax Validation
Instant error detection with clear messages — catch tab/space issues, missing colons, and more.
YAML ↔ JSON
Convert between YAML and JSON formats instantly. Useful for Kubernetes, Docker, and CI configs.
100% Private
Your config files never leave your browser. Safe for secrets, credentials, and sensitive configs.
Instant Processing
No network calls or uploads. Process locally at full speed, even for large YAML files.
Works Offline
Built as a PWA — format and validate YAML without an internet connection.
Common YAML Use Cases
Docker Compose
Validate and format docker-compose.yml files before deploying containers.
Kubernetes Manifests
Ensure your pod specs, deployments, and service configs have correct indentation.
GitHub Actions
Format and validate .github/workflows/*.yml workflow definitions.
Ansible Playbooks
Fix indentation in complex Ansible playbooks and role configurations.
CI/CD Pipelines
Validate GitLab CI, CircleCI, and other CI/CD pipeline configurations.
Application Configs
Format Spring Boot application.yml, Rails config, and other app settings.
Frequently Asked Questions
What is YAML and where is it used?
YAML (YAML Ain't Markup Language) is a human-readable data serialization format. It's widely used for configuration files in Docker Compose, Kubernetes manifests, GitHub Actions workflows, Ansible playbooks, CI/CD pipelines, and application configs (e.g., Rails, Spring Boot). Its indentation-based syntax makes it readable but also error-prone.
What are the most common YAML errors?
The most common YAML errors are: (1) using tabs instead of spaces for indentation, (2) inconsistent indentation levels, (3) missing space after colons in key-value pairs, (4) unquoted strings containing special characters like : or #, and (5) incorrect list indentation. A YAML validator catches all of these instantly.
How do I fix YAML indentation?
YAML requires consistent space-based indentation (tabs are not allowed). Use 2 spaces per level (the most common convention). Our YAML formatter automatically fixes indentation by parsing your YAML and re-serializing it with proper, consistent spacing.
Can I convert YAML to JSON and back?
Yes! ToolCove offers a dedicated YAML ↔ JSON Converter that converts between the two formats instantly. YAML is a superset of JSON, so any valid JSON is also valid YAML. Converting from YAML to JSON is useful when you need to use the data in JavaScript or send it to an API.
Is my YAML data secure?
Absolutely. ToolCove's YAML formatter runs 100% client-side in your browser. Your YAML data — including Kubernetes secrets, Docker Compose configs, and CI/CD pipeline definitions — is never sent to any server.
Does this tool support multi-document YAML?
The formatter handles single-document YAML files, which covers the vast majority of use cases (Docker Compose, GitHub Actions, Kubernetes pods, application configs). For multi-document YAML (files with --- separators), format each document section individually.
Format your YAML now
Free, instant, private. No sign-up required.
Last updated: March 2026