diff --git a/config/dm.php b/config/dm.php
new file mode 100644
index 000000000..658b5646e
--- /dev/null
+++ b/config/dm.php
@@ -0,0 +1,76 @@
+<?php
+
+return [
+
+    /*
+    |--------------------------------------------------------------------------
+    | Group conversations
+    |--------------------------------------------------------------------------
+    |
+    | A conversation is identified by its set of participants. The limit counts
+    | everyone in the conversation, including the person who started it.
+    | Inbound messages addressed to more actors than this are dropped.
+    |
+    */
+
+    'groups' => [
+        'enabled' => (bool) env('DM_GROUPS_ENABLED', true),
+        'max_participants' => (int) env('DM_MAX_PARTICIPANTS', 10),
+    ],
+
+    /*
+    |--------------------------------------------------------------------------
+    | Message limits
+    |--------------------------------------------------------------------------
+    */
+
+    'max_message_length' => (int) env('DM_MAX_MESSAGE_LENGTH', 2000),
+
+    'max_media' => (int) env('DM_MAX_MEDIA', 4),
+
+    /*
+    |--------------------------------------------------------------------------
+    | Message requests
+    |--------------------------------------------------------------------------
+    |
+    | A recipient who does not accept messages from everyone gets the
+    | conversation as a request. Until they accept (or reply), a local sender
+    | can only send `sender_limit` messages, and at most `inbound_limit`
+    | messages from a remote sender are stored.
+    |
+    */
+
+    'requests' => [
+        'sender_limit' => (int) env('DM_REQUEST_SENDER_LIMIT', 1),
+        'inbound_limit' => (int) env('DM_REQUEST_INBOUND_LIMIT', 5),
+    ],
+
+    /*
+    |--------------------------------------------------------------------------
+    | Federation
+    |--------------------------------------------------------------------------
+    |
+    | `max_actor_fetches` caps how many unknown actors a single inbound message
+    | can make this server fetch while resolving its participants.
+    |
+    */
+
+    'federation' => [
+        'max_actor_fetches' => (int) env('DM_MAX_ACTOR_FETCHES', 5),
+    ],
+
+    /*
+    |--------------------------------------------------------------------------
+    | Backfill
+    |--------------------------------------------------------------------------
+    |
+    | The migration converts legacy direct messages inline only when there are
+    | fewer rows than this. Larger instances run
+    | `php artisan dm:backfill-conversations` themselves.
+    |
+    */
+
+    'backfill' => [
+        'inline_threshold' => (int) env('DM_BACKFILL_INLINE_THRESHOLD', 25000),
+    ],
+];