Add Errors to YAML

Add Errors to YAML breaks valid YAML on purpose by removing colons, flattening indentation, or inserting garbage lines. Test and debug with ease.

Paste your input above or import a file below.
No file chosen
Supported file types: .yaml, .yml, .txt
Total characters: 0
Options
Remove colons from some keys
Break indentation
Insert random garbage lines
Maximize output

How to Use:

  • Paste valid YAML into the input box or upload a .yaml, .yml, or .txt file
  • Turn on Remove colons from some keys to strip : from random key lines
  • Enable Break indentation to remove leading spaces from indented lines
  • Use Insert random garbage lines to add lines like !!! not-valid-yaml-here throughout your YAML
  • The output updates live as you type or toggle options
  • Click Add Errors to generate a fresh version with randomized issues
  • Hit Copy Output to copy the malformed YAML to your clipboard
  • Use Export to File to save the broken YAML as a .yaml file
  • Turn on Maximize output to expand the preview area
  • Click Clear All to reset the entire tool, including file info and toggles

What Add Errors to YAML can do:

Add Errors to YAML helps you simulate broken input for testing or demonstration. It lets you strip colons, remove indentation, or toss in invalid syntax. If you’re building a YAML validator or testing how your app handles bad configs, this tool gives you fast, repeatable chaos. You can generate new variations by clicking Add Errors again no two runs will be the same. It runs entirely in your browser, so no data leaves your device. You stay in control of what breaks and how badly.

Example:

Input:

name: Alice
location:
  city: London
  zip: 12345

Output (all toggles enabled):

name Alice
location
city: London
!!! not-valid-yaml-here
zip 12345

Common Use Cases:

Use this when building linters, testing YAML parsers, fuzzing pipelines, or teaching others how YAML fails. It helps you create flawed input fast so you can focus on improving how your code reacts.

Useful Tools & Suggestions:

If you’re adding errors to YAML for testing, Validate YAML comes in handy to confirm it’s truly broken or to double-check when you’ve fixed it. And if you want to push things further, try Truncate YAML to simulate incomplete or corrupted files.

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