Free browser-based data tool

JSON Array Deduplicator

Remove duplicate JSON objects locally in your browser.

Your files never leave your computer.All processing happens locally inside your browser.

  • Match complete objects or selected fields
  • Keep the first or last occurrence
  • Preview, copy, or download clean JSON
1

Upload JSON

Choose a .json file. It is read only by this browser tab.

Drop a JSON array file here

or use the file browser

2

Paste and validate a JSON object array

UtilityDock detects top-level fields without changing the source array.

Paste JSON or upload a file to begin.

What JSON deduplication is

Keep one record from each exact duplicate group

JSON deduplication identifies objects with the same complete value or the same selected field values and removes repeated occurrences. UtilityDock performs exact comparisons while preserving the original order of retained records and keeping the entire workflow on your computer.

Data-cleaning workflows

Remove repeated records before downstream work

Duplicate objects often appear after combining exports, retrying collection jobs, or joining data from overlapping sources. Match complete objects for exact copies or choose business-key fields such as email, identifier, and date.

  • Remove exact objects from combined exports
  • Keep one record for each customer identifier
  • Match composite keys across multiple fields
  • Retain the latest occurrence from an ordered feed
  • Reduce repeated events before analysis
  • Prepare clean fixtures and configuration records

Import preparation

Prevent duplicate records before a system import

Deduplicate locally before loading contacts, products, events, or configuration entries into another system. The summary reports the original count, removed duplicates, and final count so the change is easy to verify.

Analytics use cases

Avoid repeated observations that distort results

Duplicate events and rows can inflate counts, totals, and conversion metrics. Selecting the fields that define a unique observation creates a focused dataset without requiring SQL, scripts, or an uploaded service.

Missing and null values

Compare field presence and JSON values exactly

When selected-field matching is used, missing fields match other missing fields and null matchesnull. Missing and null remain distinct, while nested objects are compared by value rather than property order.

Examples

Choose the comparison that represents uniqueness

GoalDeduplication method
Remove exact copied recordsEntire object
Keep one record per accountaccountId
Keep one daily event per useruserId + date
Retain the newest ordered recordSelected fields + Keep Last

Data Toolkit

Continue with related UtilityDock JSON workflows

FAQ

Questions about removing duplicate JSON objects

Does UtilityDock upload or store my JSON?

No. Your files never leave your computer. Validation, field detection, deduplication, preview, copying, and download creation all happen locally inside your browser.

What JSON shape can I deduplicate?

Version 1 accepts a non-empty array of JSON objects at the document root. You can compare every object value or one or more detected top-level fields.

Does complete-object matching ignore property order?

Yes. Objects with the same properties and values are duplicates even when their property order differs. Array order inside an object remains meaningful.

How are missing and null field values handled?

Missing and null are distinct. Records missing the same selected field match one another, while null matches null. A missing field does not match a field explicitly set to null.

What happens when I select multiple fields?

Two records are duplicates only when every selected field has the same exact JSON value and presence state.

What is the difference between keeping first and last?

Keep First retains the earliest record in each duplicate group. Keep Last retains the latest. Retained records preserve their original relative order.

Does this tool perform fuzzy matching?

No. Version 1 uses exact JSON values and does not support fuzzy matching, regular expressions, custom comparison scripts, or APIs.