diff --git a/app/boxes.py b/app/boxes.py
index 19a92f8..8ebd7e2 100644
--- a/app/boxes.py
+++ b/app/boxes.py
@@ -32,6 +32,8 @@ from app.config import BLOCKED_SERVERS
 from app.config import ID
 from app.config import MANUALLY_APPROVES_FOLLOWERS
 from app.config import set_moved_to
+from app.config import stream_visibility_callback
+from app.customization import ObjectInfo
 from app.database import AsyncSession
 from app.outgoing_activities import new_outgoing_activity
 from app.source import dedup_tags
@@ -1881,16 +1883,30 @@ async def _process_note_object(
 
     is_from_following = ro.actor.ap_id in {f.ap_actor_id for f in following}
     is_reply = bool(ro.in_reply_to)
-    is_local_reply = (
+    is_local_reply = bool(
         ro.in_reply_to
         and ro.in_reply_to.startswith(BASE_URL)
         and ro.content  # Hide votes from Question
     )
     is_mention = False
+    hashtags = []
     tags = ro.ap_object.get("tag", [])
     for tag in ap.as_list(tags):
         if tag.get("name") == LOCAL_ACTOR.handle or tag.get("href") == LOCAL_ACTOR.url:
             is_mention = True
+        if tag.get("type") == "Hashtag":
+            if tag_name := tag.get("name"):
+                hashtags.append(tag_name)
+
+    object_info = ObjectInfo(
+        is_reply=is_reply,
+        is_local_reply=is_local_reply,
+        is_mention=is_mention,
+        is_from_following=is_from_following,
+        hashtags=hashtags,
+        actor_handle=ro.actor.handle,
+        remote_object=ro,
+    )
 
     inbox_object = models.InboxObject(
         server=urlparse(ro.ap_id).hostname,
@@ -1908,9 +1924,7 @@ async def _process_note_object(
         activity_object_ap_id=ro.activity_object_ap_id,
         og_meta=await opengraph.og_meta_from_note(db_session, ro),
         # Hide replies from the stream
-        is_hidden_from_stream=not (
-            (not is_reply and is_from_following) or is_mention or is_local_reply
-        ),
+        is_hidden_from_stream=not stream_visibility_callback(object_info),
         # We may already have some replies in DB
         replies_count=await _get_replies_count(db_session, ro.ap_id),
     )
diff --git a/app/config.py b/app/config.py
index 54bd4e1..e8e2a4d 100644
--- a/app/config.py
+++ b/app/config.py
@@ -16,6 +16,8 @@ from loguru import logger
 from mistletoe import markdown  # type: ignore
 
 from app.customization import _CUSTOM_ROUTES
+from app.customization import _StreamVisibilityCallback
+from app.customization import default_stream_visibility_callback
 from app.utils.emoji import _load_emojis
 from app.utils.version import get_version_commit
 
@@ -262,3 +264,14 @@ def verify_csrf_token(
 
 def hmac_sha256() -> hmac.HMAC:
     return hmac.new(CONFIG.secret.encode(), digestmod=hashlib.sha256)
+
+
+stream_visibility_callback: _StreamVisibilityCallback
+try:
+    from data.stream import (  # type: ignore  # noqa: F401, E501
+        custom_stream_visibility_callback,
+    )
+
+    stream_visibility_callback = custom_stream_visibility_callback
+except ImportError:
+    stream_visibility_callback = default_stream_visibility_callback
diff --git a/app/customization.py b/app/customization.py
index abb9062..73d2e65 100644
--- a/app/customization.py
+++ b/app/customization.py
@@ -1,12 +1,19 @@
+from dataclasses import dataclass
 from pathlib import Path
+from typing import TYPE_CHECKING
 from typing import Any
 from typing import Callable
 
 from fastapi import APIRouter
 from fastapi import Depends
 from fastapi import Request
+from loguru import logger
 from starlette.responses import JSONResponse
 
+if TYPE_CHECKING:
+    from app.ap_object import RemoteObject
+
+
 _DATA_DIR = Path().parent.resolve() / "data"
 _Handler = Callable[..., Any]
 
@@ -110,3 +117,38 @@ def get_custom_router() -> APIRouter | None:
             router.add_api_route(path, handler.handler)
 
     return router
+
+
+@dataclass
+class ObjectInfo:
+    # Is it a reply?
+    is_reply: bool
+
+    # Is it a reply to an outbox object
+    is_local_reply: bool
+
+    # Is the object mentioning the local actor
+    is_mention: bool
+
+    # Is it from someone the local actor is following
+    is_from_following: bool
+
+    # List of hashtags, e.g. #microblogpub
+    hashtags: list[str]
+
+    # @dev@microblog.pub
+    actor_handle: str
+
+    remote_object: "RemoteObject"
+
+
+_StreamVisibilityCallback = Callable[[ObjectInfo], bool]
+
+
+def default_stream_visibility_callback(object_info: ObjectInfo) -> bool:
+    logger.info(f"{object_info=}")
+    return (
+        (not object_info.is_reply and object_info.is_from_following)
+        or object_info.is_mention
+        or object_info.is_local_reply
+    )