diff --git a/alembic/versions/030_add_onboarding_completed.py b/alembic/versions/030_add_onboarding_completed.py
new file mode 100644
index 0000000..96f7eb4
--- /dev/null
+++ b/alembic/versions/030_add_onboarding_completed.py
@@ -0,0 +1,31 @@
+"""add_onboarding_completed
+
+Revision ID: 030_onboarding
+Revises: 029
+Create Date: 2026-04-04
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+# revision identifiers
+revision = "030_onboarding"
+down_revision = "029_add_email_digest"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "users",
+        sa.Column(
+            "onboarding_completed",
+            sa.Boolean(),
+            server_default="false",
+            nullable=False,
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("users", "onboarding_completed")
diff --git a/backend/models.py b/backend/models.py
index 4c6ffc1..4fbd236 100644
--- a/backend/models.py
+++ b/backend/models.py
@@ -169,6 +169,9 @@ class User(Base):
     is_active: Mapped[bool] = mapped_column(
         Boolean, default=True, server_default="true"
     )
+    onboarding_completed: Mapped[bool] = mapped_column(
+        Boolean, default=False, server_default="false"
+    )
     notification_preferences: Mapped[dict] = mapped_column(
         JSONB, nullable=False,
         server_default='{"email_digests": true, "digest_frequency": "daily"}',
diff --git a/backend/routers/auth.py b/backend/routers/auth.py
index 7380bc7..5727d9d 100644
--- a/backend/routers/auth.py
+++ b/backend/routers/auth.py
@@ -171,3 +171,19 @@ async def seed_invite_codes(session: AsyncSession) -> None:
         ))
         await session.commit()
         logger.info("Seeded default invite code: CHRYSOPEDIA-ALPHA-2026")
+
+
+# ── Onboarding ───────────────────────────────────────────────────────────────
+
+
+@router.post("/onboarding-complete", response_model=UserResponse)
+async def complete_onboarding(
+    current_user: Annotated[User, Depends(get_current_user)],
+    session: Annotated[AsyncSession, Depends(get_session)],
+):
+    """Mark the current user's onboarding as completed."""
+    current_user.onboarding_completed = True
+    await session.commit()
+    await session.refresh(current_user)
+    logger.info("Onboarding completed: %s", current_user.id)
+    return UserResponse.model_validate(current_user)
diff --git a/backend/schemas.py b/backend/schemas.py
index b4a57e2..96fd908 100644
--- a/backend/schemas.py
+++ b/backend/schemas.py
@@ -568,6 +568,7 @@ class UserResponse(BaseModel):
     role: str
     creator_id: uuid.UUID | None = None
     is_active: bool = True
+    onboarding_completed: bool = False
     created_at: datetime
     impersonating: bool = False