diff --git a/alembic/versions/u1s9o5p7q8_add_app_domain_to_delivery_log.py b/alembic/versions/u1s9o5p7q8_add_app_domain_to_delivery_log.py
new file mode 100644
index 0000000..1306c9f
--- /dev/null
+++ b/alembic/versions/u1s9o5p7q8_add_app_domain_to_delivery_log.py
@@ -0,0 +1,33 @@
+"""Add app_domain to ap_delivery_log for per-domain idempotency
+
+Revision ID: u1s9o5p7q8
+Revises: t0r8n4o6p7
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "u1s9o5p7q8"
+down_revision = "t0r8n4o6p7"
+
+
+def upgrade() -> None:
+    op.add_column(
+        "ap_delivery_log",
+        sa.Column("app_domain", sa.String(128), nullable=False, server_default="federation"),
+    )
+    op.drop_constraint("uq_delivery_activity_inbox", "ap_delivery_log", type_="unique")
+    op.create_unique_constraint(
+        "uq_delivery_activity_inbox_domain",
+        "ap_delivery_log",
+        ["activity_id", "inbox_url", "app_domain"],
+    )
+
+
+def downgrade() -> None:
+    op.drop_constraint("uq_delivery_activity_inbox_domain", "ap_delivery_log", type_="unique")
+    op.drop_column("ap_delivery_log", "app_domain")
+    op.create_unique_constraint(
+        "uq_delivery_activity_inbox",
+        "ap_delivery_log",
+        ["activity_id", "inbox_url"],
+    )
diff --git a/events/handlers/ap_delivery_handler.py b/events/handlers/ap_delivery_handler.py
index 0ac9299..7a175bf 100644
--- a/events/handlers/ap_delivery_handler.py
+++ b/events/handlers/ap_delivery_handler.py
@@ -181,51 +181,49 @@ async def on_any_activity(activity: APActivity, session: AsyncSession) -> None:
         log.debug("No followers to deliver to for %s", activity.activity_id)
         return
 
-    # Check delivery log — skip inboxes we already delivered to (idempotency)
+    # Check delivery log — skip (inbox, domain) pairs already delivered (idempotency)
     existing = (
         await session.execute(
-            select(APDeliveryLog.inbox_url).where(
+            select(APDeliveryLog.inbox_url, APDeliveryLog.app_domain).where(
                 APDeliveryLog.activity_id == activity.id,
                 APDeliveryLog.status_code < 300,
             )
         )
-    ).scalars().all()
-    already_delivered = set(existing)
+    ).all()
+    already_delivered: set[tuple[str, str]] = {(r[0], r[1]) for r in existing}
 
-    # Group followers by app_domain so we deliver with the correct
-    # actor URL and signing domain for each subscriber.
-    # If the same inbox appears under multiple app_domains, prefer
-    # the per-app domain (it's what the follower subscribed to).
-    inbox_to_domain: dict[str, str] = {}
+    # Collect all (inbox, app_domain) pairs to deliver to.
+    # Each follower subscription gets its own delivery with the correct
+    # actor identity, so followers of @user@blog and @user@federation
+    # both see posts on their respective actor profiles.
+    delivery_pairs: set[tuple[str, str]] = set()
     for f in followers:
         if not f.follower_inbox:
             continue
-        if f.follower_inbox in already_delivered:
-            continue
         app_dom = f.app_domain or "federation"
-        # Per-app domain wins over aggregate if both exist
-        if f.follower_inbox not in inbox_to_domain or app_dom != "federation":
-            inbox_to_domain[f.follower_inbox] = app_dom
+        pair = (f.follower_inbox, app_dom)
+        if pair not in already_delivered:
+            delivery_pairs.add(pair)
 
-    if not inbox_to_domain:
+    if not delivery_pairs:
         if already_delivered:
-            log.info("All inbox(es) already delivered for %s", activity.activity_id)
+            log.info("All deliveries already done for %s", activity.activity_id)
         return
 
     if already_delivered:
         log.info(
-            "Skipping %d already-delivered inbox(es), delivering to %d remaining",
-            len(already_delivered), len(inbox_to_domain),
+            "Skipping %d already-delivered, delivering to %d remaining",
+            len(already_delivered), len(delivery_pairs),
         )
 
     # Group by domain to reuse activity JSON per domain
     domain_inboxes: dict[str, list[str]] = defaultdict(list)
-    for inbox_url, app_dom in inbox_to_domain.items():
+    for inbox_url, app_dom in delivery_pairs:
         domain_inboxes[app_dom].append(inbox_url)
 
     log.info(
-        "Delivering %s to %d inbox(es) for @%s across %d domain(s)",
-        activity.activity_type, len(inbox_to_domain),
+        "Delivering %s to %d target(s) for @%s across %d domain(s)",
+        activity.activity_type, len(delivery_pairs),
         actor.preferred_username, len(domain_inboxes),
     )
 
@@ -242,6 +240,7 @@ async def on_any_activity(activity: APActivity, session: AsyncSession) -> None:
                     session.add(APDeliveryLog(
                         activity_id=activity.id,
                         inbox_url=inbox_url,
+                        app_domain=app_dom,
                         status_code=status_code,
                     ))
                     await session.flush()
diff --git a/models/federation.py b/models/federation.py
index b5b780b..daef64a 100644
--- a/models/federation.py
+++ b/models/federation.py
@@ -454,12 +454,13 @@ class APDeliveryLog(Base):
         Integer, ForeignKey("ap_activities.id", ondelete="CASCADE"), nullable=False,
     )
     inbox_url: Mapped[str] = mapped_column(String(512), nullable=False)
+    app_domain: Mapped[str] = mapped_column(String(128), nullable=False, server_default="federation")
     status_code: Mapped[int | None] = mapped_column(Integer, nullable=True)
     delivered_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), nullable=False, server_default=func.now(),
     )
 
     __table_args__ = (
-        UniqueConstraint("activity_id", "inbox_url", name="uq_delivery_activity_inbox"),
+        UniqueConstraint("activity_id", "inbox_url", "app_domain", name="uq_delivery_activity_inbox_domain"),
         Index("ix_ap_delivery_activity", "activity_id"),
     )