diff --git a/alembic/versions/0012_fc3b_app_setting.py b/alembic/versions/0012_fc3b_app_setting.py
new file mode 100644
index 0000000..42c06eb
--- /dev/null
+++ b/alembic/versions/0012_fc3b_app_setting.py
@@ -0,0 +1,36 @@
+"""fc3b: app_setting key/value table
+
+Revision ID: 0012
+Revises: 0011
+Create Date: 2026-05-20
+
+A simple key/value table for small app settings that don't fit
+ImportSettings. Initially seeds only `extension_api_key` (done in
+create_app on first boot — not in the migration, to keep it
+deterministic and independent of randomness).
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0012"
+down_revision: Union[str, None] = "0011"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "app_setting",
+        sa.Column("key", sa.String(length=64), primary_key=True),
+        sa.Column("value", sa.Text(), nullable=False),
+        sa.Column(
+            "updated_at", sa.DateTime(timezone=True),
+            nullable=False, server_default=sa.func.now(),
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_table("app_setting")
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index 25c2d12..609e2ff 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -1,5 +1,6 @@
 """All ORM models. Import this module to make every model visible to Alembic."""
 
+from .app_setting import AppSetting
 from .artist import Artist
 from .base import Base
 from .credential import Credential
@@ -22,6 +23,7 @@ from .tag_suggestion_rejection import TagSuggestionRejection
 
 __all__ = [
     "Base",
+    "AppSetting",
     "Artist",
     "Source",
     "Credential",
diff --git a/backend/app/models/app_setting.py b/backend/app/models/app_setting.py
new file mode 100644
index 0000000..771843d
--- /dev/null
+++ b/backend/app/models/app_setting.py
@@ -0,0 +1,24 @@
+"""AppSetting — small key/value app config (extension API key, etc.).
+
+For settings that need DB persistence + runtime mutation. Use
+`ImportSettings` for the structured import-tuning settings; this
+table is for one-off scalar values keyed by string.
+"""
+
+from datetime import datetime
+
+from sqlalchemy import DateTime, String, Text, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from .base import Base
+
+
+class AppSetting(Base):
+    __tablename__ = "app_setting"
+
+    key: Mapped[str] = mapped_column(String(64), primary_key=True)
+    value: Mapped[str] = mapped_column(Text, nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False,
+        server_default=func.now(), onupdate=func.now(),
+    )
diff --git a/tests/test_migration_0012.py b/tests/test_migration_0012.py
new file mode 100644
index 0000000..a993ab4
--- /dev/null
+++ b/tests/test_migration_0012.py
@@ -0,0 +1,32 @@
+import pytest
+from sqlalchemy import select
+
+from backend.app.models import AppSetting
+
+pytestmark = pytest.mark.integration
+
+
+@pytest.mark.asyncio
+async def test_app_setting_table_round_trip(db):
+    db.add(AppSetting(key="extension_api_key", value="abc123"))
+    await db.flush()
+    row = (await db.execute(
+        select(AppSetting).where(AppSetting.key == "extension_api_key")
+    )).scalar_one()
+    assert row.value == "abc123"
+    assert row.updated_at is not None
+
+
+@pytest.mark.asyncio
+async def test_app_setting_upsert(db):
+    db.add(AppSetting(key="k", value="v1"))
+    await db.flush()
+    row = (await db.execute(
+        select(AppSetting).where(AppSetting.key == "k")
+    )).scalar_one()
+    row.value = "v2"
+    await db.flush()
+    again = (await db.execute(
+        select(AppSetting.value).where(AppSetting.key == "k")
+    )).scalar_one()
+    assert again == "v2"