YAML Line 5 Did Not Find Expected Key

Complete guide to fixing YAML syntax and parsing errors

Last updated: November 2024 • 6 min read

Understanding the Error

YAML: line 5: did not find expected key

This error indicates that the YAML parser encountered a syntax issue at line 5. The parser expected to find a key-value pair but found something else instead. Common causes include incorrect indentation, missing colons, or invalid characters.

Common Causes

1. Incorrect Indentation

YAML is indentation-sensitive. Mixing tabs and spaces or inconsistent indentation causes errors.

Incorrect:

name: John
  age: 30
  city: New York
address: 123 Main St

Correct:

name: John
age: 30
city: New York
address: 123 Main St

2. Missing Colon

Keys must be followed by a colon and space before the value.

Incorrect:

name John
age 30

Correct:

name: John
age: 30

3. Invalid Characters in Keys

Keys containing special characters must be quoted.

Incorrect:

user-name: John
email@domain: test@example.com

Correct:

"user-name": John
"email@domain": test@example.com

4. Nested Structure Issues

Incorrect nesting of maps and lists causes parsing errors.

Incorrect:

person:
name: John
  age: 30

Correct:

person:
  name: John
  age: 30

Step-by-Step Fix

Step 1: Check Line 5

Examine line 5 and the surrounding lines for syntax issues:

  • Verify indentation matches the parent level
  • Ensure there's a colon after the key
  • Check for tabs mixed with spaces
  • Look for special characters that need quoting

Step 2: Validate Indentation

YAML requires consistent indentation (typically 2 spaces):

# Use 2 spaces for each level
level1:
  level2:
    level3: value

Step 3: Use a YAML Validator

Validate your YAML file using online tools or command-line validators:

# Using Python
python -c "import yaml; yaml.safe_load(open('file.yaml'))"

# Using yamllint
yamllint file.yaml

# Online validator
# Use YAML.cc validator tool

Example: Fixing a Common Error

Problematic YAML (causes error at line 5):

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data
  key1: value1
  key2: value2

Error: Missing colon after "data" on line 4, causing parser to fail at line 5

Fixed YAML:

apiVersion: v1
kind: ConfigMap
metadata:
  name: my-config
data:
  key1: value1
  key2: value2

Solution: Added colon after "data" to properly define the key

Prevention Tips

  • •
    Use spaces, not tabs - Configure your editor to show whitespace and convert tabs to spaces
  • •
    Consistent indentation - Use 2 spaces per indentation level consistently
  • •
    Validate before use - Run YAML through a validator before deploying or committing
  • •
    Use YAML-aware editors - Editors like VS Code with YAML extensions provide real-time validation
  • •
    Quote special keys - When in doubt, quote keys containing special characters

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