Building integrations

How do I clear an attachment or lookup field through an integration?

Update an item can't clear a field, so use Make an HTTP call (Custom) to the process admin update endpoint with the field set to null.

How-to

Short answer: Use the HTTP connector instead of Update an item. Call the process admin update endpoint and set the field to null in the request body.

Why it happens

Leaving a field empty in Update an item doesn't change it, and passing null in that action throws an error.

How to fix it

  1. In your integration, add the action Make an HTTP call (Custom) from the HTTP connector and set the method to PUT.
  2. Add the access key as HTTP headers: X-Access-Key-Id and X-Access-Key-Secret. The key must belong to a user or service account with the Process Admin role on that process.
  3. Set the URL to the admin update endpoint: https://{subdomain}.kissflow.com/process/2/:account_id/admin/:process_id/:instance_id
  4. In the JSON body, set the field ID to null, for example { "Attachment_field_id": null }.
  5. Test the action with real values, then map the fields and turn on the integration.

This removes an existing attachment or clears a lookup value. For the endpoint details, see API and SDK documentation.

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