JSON Deduplicate
Remove duplicate array values, including nested arrays, while preserving the first occurrence.
Remove duplicate array values, including nested arrays, while preserving the first occurrence.
JSON Deduplicate removes repeated items from arrays while keeping the first occurrence. It also walks nested objects and arrays, so duplicate values inside a larger JSON document can be cleaned without changing the surrounding structure.
Use this browser-based JSON deduplicator for tags, identifiers, imported records, API results, and test data. The result is formatted for readability and processing stays on your device, which means the JSON you paste is not uploaded.
Duplicate objects are compared by their JSON value, so identical objects are collapsed even when they occur in different parts of an array. Review the cleaned output when object order or duplicate records has business meaning.
Deduplication is useful after combining API responses, importing lists, or preparing fixtures for automated tests. Because the first occurrence is retained, the output keeps the original ordering of unique values instead of sorting the data unexpectedly.
Use the copy control to move a checked result into another local development workflow.
This makes the output easy to review before it is copied into a script, test, configuration file, or API workflow.