diff --git a/core/app.py b/core/app.py
index 2f271243..4ce61a2f 100644
--- a/core/app.py
+++ b/core/app.py
@@ -34,13 +34,12 @@
 @asynccontextmanager
 async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
     """
-    Application lifespan event handler to initialize the database and lexicon.
+    Application lifespan event handler to seed data in development mode.
     """
     if settings.get_enum("MODE") == "development":
-        erase_and_rebuild_db()
         from transfers.seed import seed_all
 
-        seed_all(10)
+        seed_all(10, skip_if_exists=True)
 
     register_routes(app)
     yield
diff --git a/transfers/seed.py b/transfers/seed.py
index 5dd0ea83..f3cf741b 100644
--- a/transfers/seed.py
+++ b/transfers/seed.py
@@ -54,8 +54,31 @@ def get_terms_by_category(s, category_name: str) -> list[LexiconTerm]:
     )
 
 
-def seed_all(n: int = 5):
+def ensure_seed_prereqs() -> None:
+    """Ensure that lexicon and parameter data exist before seeding."""
+    from core.initializers import init_lexicon, init_parameter
+
+    with session_ctx() as s:
+        has_lexicon = s.scalar(select(LexiconTerm.id).limit(1)) is not None
+        has_parameter = s.scalar(select(Parameter.id).limit(1)) is not None
+
+    if not has_lexicon:
+        init_lexicon()
+    if not has_parameter:
+        init_parameter()
+
+
+def contact_data_exists() -> bool:
+    with session_ctx() as s:
+        return s.scalar(select(Contact.id).limit(1)) is not None
+
+
+def seed_all(n: int = 5, skip_if_exists: bool = False):
     """Seed roughly `n` of each main entity and connect them."""
+    if skip_if_exists and contact_data_exists():
+        print("Contact data exists; skipping seeding.")
+        return
+    ensure_seed_prereqs()
     new_mexico_bounds = [
         (36.9, -106.6),  # Taos area
         (35.1, -106.6),  # Albuquerque
@@ -433,6 +456,8 @@ def seed_all(n: int = 5):
             print(f"Error committing seed data: {e}")
             raise
 
+    print("Seeding data finished.")
+
 
 if __name__ == "__main__":
     seed_all(5)