What is YAML?
A plain-English definition, and the tools that work with it.
YAML is a human-friendly data format that uses indentation instead of brackets, making it easy to read and write. It's the go-to for configuration files (CI pipelines, Docker Compose, Kubernetes) where clarity matters more than compactness.
- YAML relies on indentation for structure, so consistent spaces (never tabs) are essential: mis-indentation is the top error.
- It's a superset of JSON: any JSON is valid YAML, but YAML adds comments and cleaner syntax.
- Great for config humans edit by hand. Less suited to high-volume machine data exchange, where JSON is faster to parse.
Tools for YAML
Free, private and in your browser. No sign-up.
YAML Formatter
Format, clean and re-indent YAML in your browser, or convert YAML ↔ JSON, with key sorting, flow/block style and the exact error line + column. Nothing is uploaded.
JSON Formatter
Format, validate and minify JSON in your browser with pinpoint error line + column, jump-to-error, key sorting and live editing: nothing is uploaded.
JSON Validator
Validate JSON against RFC 8259 with the exact error line, column and a caret under the bad character. Get plain-English explanations, one-click auto-fix for trailing commas and single quotes, plus depth, key-count and type stats, nothing uploaded.
JSON to TypeScript
Convert JSON to TypeScript interfaces or types instantly, with merged unions across array items, optional-from-null, readonly, export and naming controls, 100% in your browser.
YAML problems we solve
Hit one of these? Here's the fix.
- My JSON is invalid and I can't find the error'Unexpected token' almost always means one stray character. A validator points straight at it so you're not hunting by eye.
- My code or data is minified and unreadableOne long line of minified everything? Pick the matching formatter and get properly indented, readable code back.
Frequently asked questions
Related terms
- JSONJSON (JavaScript Object Notation) is a lightweight, text-based format for structured data, built from key–value pairs and lists. It's the standard way apps and APIs exchange data because it's easy for both humans and machines to read.
- XMLXML (eXtensible Markup Language) is a text format that stores data in nested, custom tags, like HTML but for arbitrary data rather than web pages. It's used for configuration, data exchange, sitemaps and document formats, prized for being both human-readable and strictly structured.
Keep exploring
Problems we solve
Definitions
From the blog
- How to Generate TypeScript Types from JSON (API Responses Made Type-Safe)
- JSON-LD vs. Microdata vs. RDFa: Which Structured Data Format Should You Use?
- FAQ Schema: A Practical Guide to Winning Rich Results
- MP3 vs WAV vs FLAC: Audio Formats Explained
- How to Fix Invalid JSON Errors: The Complete Troubleshooting Guide
Common tasks
Try YAML Formatter
Free, private and instant. Everything runs in your browser.