---
title: Custom blocklists
slug: campaign/docs/custom-blocklists
docTags: 
createdAt: 2026-07-20T15:45:34.646Z
---

:::hint{type="info"}
**Note**

To enable this feature, contact [customer support](docId\:ZWe1T3UPz3JW6_4mc76qV).
:::

This optional feature lets you exclude mailing recipients who are not part of the global blocklist. The global blocklist is always applied.

You can create multiple custom blocklists and fill them manually or via CSV data import. Then, use a [Block node](docId\:k_hpwC2i6hpPhMRGk2ozV) to add custom blocklists to a campaign in Smart Campaigns or to a [transactional mail](docId\:V9V1TFA5Z2cDQH6hNQy59). As a result, you specify which recipients besides the global blocklist should not receive a mailing.

## [custom-blocklists.mdx](docId\:FPo-LpYndAzSMD5mhRHPR)Creating custom blocklists

:::Paragraph{listStyleType="decimal" indent="2"}
Open the Optimizely Campaign [menu](docId\:PmNPgvNucBrAG5Rw8f41f) and select **Blocklist** > **Custom Blocklists**.
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:::Paragraph{listStyleType="decimal" listStart="2" indent="2"}
Click **Create…**.
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:::Paragraph{listStyleType="decimal" listStart="3" indent="2"}
Enter a name for the custom blocklist.
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Select one of the hash algorithms supported by Optimizely Campaign. If the entries in your blocklist do not use hash algorithms, select **None**.
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:::hint{type="info" indent="3"}
**Tip**

As long as your custom blocklist is empty, you may change the hash algorithm anytime.
:::

::Image[]{src="https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/gYo_xNRVhJfXCw8pOBQ8B-20260720-145308.png" size="100" caption="Image: Selecting hash algorithm" alt="Image: Selecting hash algorithm" isUploading="false" showCaption="true" indent="3"}

:::Paragraph{listStyleType="decimal" listStart="5" indent="2"}
Click **Submit**.
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:::hint{type="info"}
**Tip**

You can delete all entries in a custom blocklist by clicking **Clear**.
:::

## [custom-blocklists.mdx](docId\:FPo-LpYndAzSMD5mhRHPR)Adding and editing recipients manually

1. Open the Optimizely Campaign [menu](docId\:PmNPgvNucBrAG5Rw8f41f) and select **Blocklist** > **Overview**.
2. Under **Blocklist Selection**, click **Custom Blocklist** and select the blocklist you want to edit.

   ![Image: Custom blacklist in Overview](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/9NW79AGJW6-jptO1uFH9I-20260720-145308.png "Image: Custom blacklist in Overview")
3. Edit the custom blocklist by clicking the **Add…**, **Edit…** and **Delete** button. For more information, see [Blocklist overview](docId\:bN4TdJLisJkf2KjuWe-wA).

## [custom-blocklists.mdx](docId\:pnPmK0ktxXLA9swxx4K5D)Importing blocklist entries from a CSV file

:::hint{type="info"}
**Note**

The CSV file's hash algorithm must match the hash algorithm of the selected blocklist. If not, an error message is displayed.
:::

To import entries from a CSV file into a custom blocklist, perform the following steps:

1. In the menu bar, select **Blocklist** > **Import**.
2. Under **Upload**, click the **Choose File…** button and select a CSV file on your local hard disk.
3. Click **Import Options** to upload the file.
4. Under **Blocklist Selection**, click **Custom Blocklist**.
5. Select the custom blocklist to which you want to import the CSV file.
6. In the section **Import Type Selection**, select if you want to add the new entries to the existing ones or empty the selected blocklist before importing.
7. In the section **Character Encoding and CSV Options**, under **Specify the Hash Algorithm Used in the Import File**, select your CSV file's hash algorithm. If your CSV file entries use no hash algorithm, select **None**.
8. Optional: change other CSV file options as necessary (see [Import blocklists](docId\:qp5MIA3flaNUqOLaRDCuG)).
9. Click the **Reason** button. You can optionally enter a reason for blocklisting the imported entries. The reason applies to all imported entries.
10. To start the import, click **Finished**.