diff --git a/app/modules/loyalty/schemas/program.py b/app/modules/loyalty/schemas/program.py
index b8bab56f..ac1e027f 100644
--- a/app/modules/loyalty/schemas/program.py
+++ b/app/modules/loyalty/schemas/program.py
@@ -10,7 +10,7 @@ Merchant-based programs:
 
 from datetime import datetime
 
-from pydantic import BaseModel, ConfigDict, Field
+from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
 class PointsRewardConfig(BaseModel):
@@ -83,6 +83,13 @@ class ProgramCreate(BaseModel):
         description="Minimum purchase amount to earn points (0 = no minimum)",
     )
 
+    @field_validator("minimum_purchase_cents", mode="before")
+    @classmethod
+    def _coerce_purchase_cents_none_to_zero(cls, v):
+        # Form sends null for empty number inputs; DB column is NOT NULL
+        # with default 0, and 0 already means "no minimum" semantically.
+        return 0 if v is None else v
+
     # Future: Tier configuration
     tier_config: list[TierConfig] | None = Field(
         None,