---
title: Deduplicate mode
url: https://www.tines.com/docs/actions/types/event-transformation/deduplicate/
updated: 2026-02-20T15:25:24+00:00
---

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# Deduplicate mode

*[View on tines.com](https://www.tines.com/docs/actions/types/event-transformation/deduplicate/)*

Specify a field in an incoming events and only emit the event if that field contains a unique value.

## Features

- Define how many historical events from previous story runs should be used to determine if value in field is unique.
- Specify a period of time to check for duplicates.
- Specify the field in an incoming event to use as a measure of uniqueness.
- If an event is deemed unique, it will be emitted. If it is deemed a duplicate, it will be ignored and a corresponding log entry will be created.

## Configuration Options

- `mode`: 'deduplicate'
- `path`: a JSON wrapped path the value of which should be used to determine the uniqueness of the event.
- `lookback`: (Optional: must use either `lookback` or `period`) Number of past events (maximum of 1000) to examine for uniqueness.
- `period`: (Optional: must use either `lookback` or `period`) Number of seconds to use for deduplication. When an event is received, subsequent events will not be emitted until this period has elapsed.
- `emit_duplicates`: (Optional) Set to true if duplicate events should be emitted. `'unique_event': false` will be included in emitted event.
- `tolerance`: (Optional) The number of events with the same value to allow before deduplicating. Events of the same value will be treated as unique until the provided tolerance is reached.

## Emitted Events

```json
{
  "unique_event": true
}
```

## Example Configuration Options

Check the last 100 received events and only emit an event if the value in the `person.name` field is unique. To see this on your storyboard, copy the JSON below into an event transform action by selecting `View code` at the top right of the action and pasting the JSON in.

```json
{
  "mode": "deduplicate",
  "lookback": "100",
  "path": "<<person.name>>"
}
```