Skip to content
Input
YAML
Limit
1 MiB
Runtime
Browser

Merge two YAML mappings with an explicit policy

Combine a base mapping with an overlay under a chosen collision policy instead of relying on undocumented precedence.

Local processingNo sign-upNo content logging

Merge YAML

Inputs are limited to 1 MiB and stay in this browser tab.

Paste or edit the source. Tool Swim does not upload or save it.

Top-level non-mapping documents are rejected because their merge meaning would be ambiguous.

Merged YAML mapping

Nothing is placed in a URL, account, preset, or remote log.

What this tool does

Strict, bounded, local processing

Nested mappings are combined recursively while scalar, sequence, and incompatible-type collisions follow the selected policy.

Collision policy defines the result

The merge descends only when both values are mappings. Sequences, scalars, nulls, and incompatible types are complete-value collisions handled by the selected base, overlay, or error policy.

The operation does not execute YAML merge tags, templates, environment substitutions, or application-specific inheritance rules.

Generated configuration still needs review

Merging can remove a nested default or replace an entire sequence. Compare the merged result against its base and validate it with the destination schema before deployment.

Primary references

Questions and answers

Related YAML tools

YAML ComparatorParse both documents and report additions, removals, and changed values at stable paths instead of producing a noisy line diff.YAML Schema ValidatorCheck parsed YAML values against a separately supplied JSON Schema and return structured instance paths for each supported violation.YAML FlattenerWalk nested mappings and sequences, emit one leaf per unambiguous path, and preserve scalar types in a reviewable JSON object.