YAML Linter & Formatter

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Paste any YAML and hit Lint & Format. Syntax errors are listed with their line numbers. If the input is valid, a cleanly re-indented copy is shown below.

YAML Input1 lines

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What is a YAML Linter?

A YAML linter parses your YAML and reports structural errors — tabs used instead of spaces, missing colons, inconsistent indentation — before they cause runtime failures. This tool also reformats valid YAML to 2-space indentation, so configs stay consistent across teams and CI pipelines.

How to Use

Paste your YAML into the input box.
Click Lint & Format.
If errors exist, each is listed with a line number badge — fix them and re-lint.
If the YAML is valid, the formatted output appears below. Copy it with one click.

Common YAML Errors

Tabs instead of spaces — YAML forbids tab characters for indentation. Replace all tabs with spaces.
Missing space after colon — key:value is invalid; it must be key: value.
Inconsistent indentation — Mixing 2-space and 4-space indentation within the same file causes parse errors.
Unquoted special characters — Values containing :, #, or {} must be quoted.

FAQs

Does formatting change my data?

No. Only whitespace and colon spacing are normalized. Keys, values, and structure are preserved exactly.

Does it support multi-line block scalars?

Yes. Block scalar content (lines after | or >) is preserved as-is and not re-indented.

Can I use this for Kubernetes or GitHub Actions YAML?

Yes. Any valid YAML file — Helm charts, GitHub Actions workflows, Docker Compose, Ansible playbooks — can be linted and formatted here.