> ## Documentation Index
> Fetch the complete documentation index at: https://assembly.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Import and backfill information safely

> Move existing clients into Assembly in controlled batches without sending them unexpected notifications.

Bulk imports can create or update many contacts and companies at once. Before importing, clean the source data, confirm your field mappings, remove duplicates, and test the process with a small sample.

For imports that include custom fields or update existing records, see [Advanced import](/docs/core-concepts/advanced-import).

## The safe import sequence

<Steps>
  <Step title="Prepare the destination">
    Create the necessary contact and company fields in Assembly before beginning the import, so imported values have somewhere correct to land.
  </Step>

  <Step title="Clean the source">
    Standardize names, email addresses, company relationships, dates, tags, statuses, and internal owners before you upload anything.
  </Step>

  <Step title="Control notifications">
    Mute email notifications for existing clients while importing and backfilling information. This prevents clients from receiving unexpected alerts, messages, assignments, or requests before launch. See [Client notifications](/docs/core-concepts/client-notifications).
  </Step>

  <Step title="Test a small batch">
    Import a few internal or test records and confirm that the information appears in the correct places.
  </Step>

  <Step title="Complete the migration">
    Import the remaining records in manageable batches and review any exceptions. Bulk import supports up to 200 records at a time, so larger migrations need to be split into batches.
  </Step>

  <Step title="Re-enable notifications intentionally">
    Unmute notifications only after the client experience is ready and the client is included in an active rollout group.
  </Step>
</Steps>

<Warning>
  Muting notifications during backfill is the step teams most often skip. Creating requests, uploading files, or assigning work against an unmuted client sends real email to someone who has not been told about Assembly yet.
</Warning>