Mastodon Domain Block List Export: Step-by-Step

You need to export your domain block list from Mastodon to share with another instance or to back up your moderation settings. Mastodon stores these blocks as a JSON file that contains every domain your instance has silenced, suspended, or limited. This article explains exactly how to generate that export file from your Mastodon admin panel and what each block type means.

The export feature is built into every Mastodon instance version 3.0 and later. You must have Administrator or Moderator role on the instance to access the export function. The process takes about 30 seconds and produces a downloadable file you can import into any other Mastodon instance.

What the Domain Block Export Contains

The domain block export file is a JSON document that lists every domain your instance has actively blocked. Mastodon applies three severity levels to domain blocks:

Silence: Posts from the domain are hidden from the public timeline and local timeline. Users must manually follow accounts from that domain to see their content.

Suspend: All content from the domain is removed from your instance. No accounts from that domain can interact with your users.

Limit: A softer restriction that reduces the visibility of content from the domain in federated timelines. This is less severe than silence.

Each block entry in the export also includes optional fields such as a public note explaining why the block was applied and an obfuscation setting that hides the full domain name from non-admin users. The export does not include any user data, post content, or private information.

Before exporting, verify that your instance is running Mastodon version 3.0 or later. Older versions do not have the export feature. You can check your version in Administration > Server > About.

Steps to Export the Domain Block List

Follow these steps exactly to download your domain block list from the Mastodon admin panel.

1. Log in to your Mastodon instance as an administrator or moderator
   Open your instance URL in a web browser. Enter your email and password. Only accounts with the Admin or Moderator role can see the Administration menu.
2. Navigate to the Administration panel
   Click the hamburger menu icon (three horizontal lines) in the top-right corner of the page. Select Administration from the dropdown menu. If you do not see this option, your account does not have the required permissions.
3. Open the Server section
   In the left sidebar of the Administration panel, click Server. This expands a submenu with options for settings, about, domain blocks, and more.
4. Click Domain Blocks
   Under the Server section, select Domain Blocks. This page displays a table of every domain your instance has blocked, along with the severity level and any notes.
5. Click the Export button
   Above the domain blocks table, locate the Export button. It is a blue button labeled Export. Click it to trigger the file download.
6. Save the JSON file
   Your browser will download a file named domain_blocks.json. Save it to a secure location. The file contains no passwords or user data, but treat it as sensitive because it reveals your moderation policy.

After the download completes, you can open the JSON file in any text editor to view the block list. Each entry follows this structure:

{
  "domain": "bad-example.com",
  "severity": "suspend",
  "public_comment": "Spam and harassment",
  "obfuscate": true
}

The obfuscate field, when set to true, hides the middle characters of the domain from non-admin users in the admin interface.

Common Mistakes and Limitations When Exporting Domain Blocks

Export button is grayed out or missing

If the Export button appears disabled or is not visible, your Mastodon version is older than 3.0. Update your instance to the latest stable release. During the update process, the domain blocks are preserved, but the export feature only appears after the upgrade completes.

Downloaded file contains no entries

If the exported JSON file shows an empty array [], your instance has no domain blocks configured. Mastodon exports only active blocks. To verify, check the Domain Blocks page in the admin panel. If the table is empty, there are no blocks to export.

File fails to import into another instance

The exported JSON must match the exact schema expected by Mastodon. If you edited the file manually and introduced syntax errors, the import will fail. To fix this, export a fresh copy without modifications. Also ensure the target instance runs Mastodon version 3.0 or later. Older instances do not recognize the import format.

Block notes are missing after import

The export includes the public_comment field, but the import process on the target instance may truncate notes that exceed 255 characters. Keep your public comments under this limit to ensure they transfer completely.

Mastodon Domain Block Export vs Manual List

Item	Export JSON File	Manual Copy-Paste
Format	Structured JSON with severity, notes, and obfuscation settings	Plain text list of domain names
Import compatibility	Direct import into Mastodon admin panel	Must be manually re-entered into the block form one domain at a time
Speed	30 seconds for export, 30 seconds for import	Minutes to hours depending on block list size
Error risk	Low — schema is validated during import	High — typos or missed domains
Includes notes	Yes, up to 255 characters per block	Only if manually typed

Use the export method whenever you need to transfer blocks between instances or create a backup. The manual method is only useful for reviewing the list without downloading a file.

You can now export your Mastodon domain block list as a JSON file from the Administration > Server > Domain Blocks page. Use the exported file to back up your moderation rules or share them with another instance admin. For an advanced workflow, combine the export with the import feature in the same panel to synchronize block lists between multiple instances you manage.