API Automation Is Creating Duplicate Records: How to Find the Repeated Request

Why API automation creates duplicates

Duplicates come from two causes. The same source event triggers the automation more than once, or the automation creates a record every time without checking whether one already exists. Both produce duplicates but need different fixes. A repeated trigger needs deduplication at the source. A missing lookup needs a search before create step. Identify which you have before changing anything.

What to check first

Is the trigger firing more than once

A repeated trigger is the most common cause. The source event fires twice, the automation runs twice and two records are created. Check the trigger history for the source event. If the trigger fired twice, the problem is at the source, not the create action. A form submitted twice, a webhook sent twice or a status changed twice all produce repeated triggers. Repeated triggers are covered in the guide on automation running twice.

Is there a lookup before the create

Without a lookup, the automation creates a record every time it runs. Even if the trigger fires once, a second run for the same contact creates a duplicate because the automation never checks whether the record exists. A search before create step looks for an existing record and only creates one if the search returns nothing. If your automation goes straight to create, add a lookup. This is the single most effective duplicate prevention step.

Create versus update logic

The automation should create when no record exists and update when one does. If the logic always creates, duplicates accumulate. If the logic always updates, the first record is never created. The correct pattern is search, then branch on the result, then create or update based on whether a record was found. Confirm the automation follows this pattern rather than always creating.

Retries and partial success

Retries can create duplicates when a request partially succeeds. The endpoint creates the record but the response fails to return, so the automation retries and creates a second record. This is harder to detect because the trigger fired once but two records exist. A unique identifier sent with the request lets the endpoint treat the retry as the same event. This concept is called idempotency. Not all APIs support it, so check the documentation for the specific API.

Multiple automations creating the same record

Two separate automations can both create the same destination record. One workflow creates a contact from a form, another creates a contact from a webhook, and both fire for the same person. Neither knows the other exists. Map every path that creates the destination record and confirm whether more than one is running. Consolidate them or add a guard that prevents the second from creating when the first already did.

How to test it

1. 1.Trigger the source event once and count the destination records created.
2. 2.If more than one record is created, check the trigger history for repeated entries.
3. 3.If the trigger fired once, check whether the automation has a lookup before create.
4. 4.Check whether multiple automations create the same record type.
5. 5.Add a search before create step if one is missing.
6. 6.Send a unique identifier with the request if retries may be causing duplicates.