OnlineDeveloperTool
Text & Data

YAML Formatter Online

Parse YAML and print it back in a clean, consistent style.

Updated

This tool runs in your browser. No account or signup is required.

Common YAML Formatter tasks

Developers typically reach for this page when they need to format YAML online; beautify Kubernetes YAML; format Docker Compose YAML. The tool is built for quick, practical work rather than a generic demo.

What matters in a yaml formatter workflow

When developers compare online tools for this job, the useful capabilities tend to center on YAML 1.2, indentation errors, file input, compact/tree/validation. This page keeps those practical needs in mind while linking to related tools when a different workflow is a better fit.

What is YAML Formatter?

YAML Formatter loads your YAML and writes it out again in standard block style.

What problem does it solve?

Config files, exports and API payloads come in different formats, and moving between them by hand is where typos creep in.

How to use YAML Formatter

  1. Paste your data into the input box.
  2. Press Process.
  3. Copy the output, or read the error message if the input could not be parsed.

Example

Input

name: Ada
tags: [a, b]

Output

name: Ada
tags:
  - a
  - b

What you can do with YAML Formatter

  • Format YAML online
  • Clean up YAML
  • Normalize YAML

Common use cases

  • Converting a config between formats
  • Checking a document before committing it
  • Turning an export into something your code can read

Related developer tasks

  • Format YAML online
  • Clean up YAML
  • Normalize YAML

YAML formatter example

The tool parses your YAML and prints it again with consistent 2-space indentation.

name:   api
ports: [80,   443]

// formatted output
name: api
ports:
  - 80
  - 443

What the YAML formatter changes

  • Comments are removed, because the YAML is parsed to data and written back.
  • Quoting and flow style (inline lists) may change to the dumper's defaults.
  • If the YAML is invalid, you see the parser error instead of output, which also makes this a quick YAML syntax check.

Related: YAML to JSON, XML Formatter, Diff Checker

YAML Formatter FAQ

What happens if my input is invalid?

You get the parser error message instead of output, so you can find the problem.

Does it change my data?

It re-reads and re-prints the same content. Only the formatting or format changes.

Is my data sent to a server?

The processing runs in your browser, so what you paste into the tool is not uploaded for processing. As with any tool, avoid pasting live secrets you cannot afford to leak.

Will it keep my comments?

No. Comments are not part of the parsed data, so they are dropped. Format a copy if you need to keep the original comments.

Looking for something else? Browse all developer tools.

onlinedevelopertool.com is a collection of 54 free, browser-based utilities for the small jobs that interrupt real work: formatting a JSON response, decoding a token, converting a timestamp, generating a UUID or checking a hash. Each tool has its own page with a short explanation, a worked example and answers to common questions, so you can use it and learn what it does at the same time.

There is no account to create and nothing to install. Tools run in your browser, so the text you paste is processed on your own device. The one exception is the Website Status Checker, which sends a request from your browser to the address you enter.

Three steps: paste your input, click the tool, copy the result, all inside your browser
Popular developer utilities: JWT decoder, UUID generator, Base64 decoder, SHA-256 hash, regex tester and timestamp converter

What you can do here

  • JSON Tools

    Format, validate, beautify and minify JSON, generate C#, TypeScript, Java, Python, Go, PHP and Kotlin models from it, or convert between JSON, YAML and CSV.

  • Encoders & Decoders

    URL, Base64 and HTML encoding and decoding, plus a JWT decoder for reading token claims.

  • Generators & Hashes

    Generate UUIDs and JWTs, validate UUIDs, and create MD5, SHA-256 and SHA-512 hashes.

  • Web Tools

    Timestamps, color codes, query strings and cron expressions - the small things web work keeps throwing at you.

  • Text & Data

    Format XML and YAML, count text, change case, make slugs, test regex, diff two texts and convert number bases.

  • Website Checking

    Check whether a website or URL is reachable from your browser.

Quick developer reference

  • JSON

    Keys and strings must use double quotes, and trailing commas and comments are not allowed. Those are the three most common reasons a payload fails to parse.

    Validate JSON

  • JWT

    A JSON Web Token is three Base64URL parts joined by dots: header, payload and signature. Decoding shows the claims but does not prove the token is genuine; only signature verification does.

    Decode a JWT

  • Base64

    Base64 is an encoding, not encryption. Anyone can reverse it, and it makes data roughly one third larger, so never use it to hide secrets.

    Decode Base64

  • UUID

    A version 4 UUID is made of random bits and written as 8-4-4-4-12 hexadecimal characters. Collisions are astronomically unlikely, which is why they work well as identifiers.

    Generate a UUID

  • Timestamps

    A Unix timestamp counts time since 1 January 1970 UTC. Ten digits usually means seconds and thirteen digits usually means milliseconds.

    Convert a timestamp

  • Hashes

    MD5 is fine for quick checksums but is not safe for security. Prefer SHA-256 or SHA-512, and remember that hashing is one-way and is not encryption.

    Create a SHA-256 hash

Missing a tool you need? Visit the contact page and tell us what you reach for most often. You can also browse every tool or read the About page to see how the site is built and what it does with your data.