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YAML Duplicate Key Detector

Data

Find mapping keys that are duplicated within the same YAML scope, with the line and column of each repeated occurrence.

Paste a YAML file and this flags every mapping key that collides with an earlier key in the same scope, the kind of copy-paste or merge-conflict mistake that most YAML parsers silently resolve by letting the later value win. It reports the exact line and column of each repeat so you can jump straight to the fix instead of diffing the whole file by eye. Detection is scope-aware: the same key name reused in a sibling object, or across separate items in a list, is not flagged, since that is completely normal YAML structure. It is a sibling of the YAML Validator, which only checks that a file parses at all and has no opinion on duplicate keys one way or the other.

yamlduplicatelintvalidate

How to use YAML Duplicate Key Detector

  • 1.Paste a YAML file, like a Kubernetes manifest, Docker Compose file, or CI config, to scan it for duplicate mapping keys.
  • 2.Review each flagged duplicate's line and column to jump straight to the repeated key in your editor.
  • 3.Re-run after fixing a merge conflict or copy-pasted block to confirm no key collisions remain before committing.

Frequently asked questions

Why would a duplicate key even matter if the file still parses?
Most YAML parsers silently use the last occurrence of a duplicate key and drop the earlier one, which is exactly the kind of mistake that can quietly change behavior without any error at all.
Does it flag the same key name used in two different objects?
No, duplicate detection is scoped to a single mapping: the same key name in a sibling object, or in a different item of a list, is normal YAML and is never flagged.
Does it handle YAML merge keys (<<:)?
Yes for the common case: an explicit key that intentionally overrides a value pulled in through a merge key is not flagged as a false positive. Very unusual merge-key setups are out of scope.
Is my YAML sent to a server?
No, in the browser tool everything runs client-side and your file never leaves your machine.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/yaml-duplicate-key-detector \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"yaml": "name: api\nport: 8080\nname: worker\n"}'

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