YAML Merge

When both YAML documents have the same key with different values, a conflict occurs. 'Prefer left' keeps values from YAML 1, 'Prefer right' keeps values from YAML 2 (default - best for overrides), and 'Combine' attempts to merge both values when possible. The conflict report shows all detected conflicts and how they were resolved. This is crucial when merging Kubernetes configs where production values should override base values.

When both YAML files contain arrays with the same name, array handling determines the merge behavior. 'Append' combines all items from both arrays (good for lists, logs, events), 'Replace' uses only items from YAML 2 (good for complete overrides), and 'Merge' combines arrays while removing duplicates based on JSON equality. Choose based on your needs: append for accumulating items, replace for config overrides, merge for unique item lists.

Deep merge (enabled by default) recursively merges nested objects and maps at all levels of the YAML structure. Shallow merge only combines top-level keys. Deep merge is recommended for complex configuration files like Kubernetes manifests, Docker Compose files, or nested application configs where you want granular control over nested properties. Disable it only when you want to replace entire sections rather than merge their contents.

Sort Keys alphabetically orders all keys in the merged output YAML. Enable it for predictable, consistent output that's easier to compare in diffs and version control. Disable it to preserve the original key order from your source files. Note that YAML semantics don't depend on key order for objects, but some tools or humans may expect a specific order. Most users keep it disabled to maintain original structure.

Currently, the tool merges two YAML documents at a time (2-way merge). To merge three or more documents, perform sequential merges: first merge YAML 1 and YAML 2, then merge the result with YAML 3, and so on. Download or copy the merged result after each step and use it as input for the next merge operation. This approach gives you fine-grained control over merge order and conflict resolution at each step.

Absolutely! YAML Merge is perfect for Kubernetes manifests. Merge base deployments with environment-specific configs, combine ConfigMaps from different sources, consolidate multi-resource YAML files, or merge Helm values files. The tool handles nested structures, arrays of containers/volumes, and complex K8s resource definitions. Use 'prefer right' for environment overrides and 'append' for array fields like containers, volumeMounts, or env variables.

Unfortunately, no. The js-yaml library used for parsing doesn't preserve comments when loading and dumping YAML. Comments are stripped during the merge process. This is a known limitation of most YAML parsers. If you need to preserve documentation, consider maintaining comments in separate documentation files or using YAML anchors and aliases for reusable content instead of comments.

Yes! All YAML merging happens entirely in your browser using client-side JavaScript. Your YAML documents are never sent to any server, uploaded anywhere, or stored remotely. The js-yaml library and all processing run 100% locally, ensuring complete privacy and security for your Kubernetes secrets, application configs, CI/CD definitions, or any sensitive configuration data.