diff --git a/.gitignore b/.gitignore
index e5a4cfba..889fc906 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,6 +50,7 @@ coverage.xml
 *.py,cover
 .hypothesis/
 .pytest_cache/
+cache
 
 # Translations
 *.mo
diff --git a/tests/test_api.py b/tests/test_api.py
index d4db62aa..7e384a8a 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -40,10 +40,11 @@ def override_get_db():
 client = TestClient(app)
 
 USER = UserBase(user_id="user1", token="user1__Utoken")
-PRODUCT = ProductCreate(code="8001505005707")
+PRODUCT = ProductCreate(code="8001505005592")
 LOCATION = LocationCreate(osm_id=3344841823, osm_type="NODE")
 PRICE_1 = PriceCreate(
-    product_code="1111111111111",
+    product_code="8001505005707",
+    # category="en:tomatoes",
     price=3.5,
     currency="EUR",
     location_osm_id=123,
@@ -99,14 +100,14 @@ def test_create_price(user, db=override_get_db()):
     # assert db_prices[0]["owner"] == user.user_id
 
 
-def test_create_price_validation(user):
-    for price_field in [
-        "product_code",
+def test_create_price_required_fields_validation(user):
+    REQUIRED_FIELDS = [
         "price",
         "location_osm_id",
         "location_osm_type",
         "date",
-    ]:
+    ]
+    for price_field in REQUIRED_FIELDS:
         PRICE_WITH_FIELD_MISSING = PRICE_1.model_copy(update={price_field: None})
         response = client.post(
             "/prices",
@@ -116,11 +117,97 @@ def test_create_price_validation(user):
         assert response.status_code == 422
 
 
+def test_create_price_product_code_pattern_validation(user):
+    # product_code cannot be an empty string, nor contain letters
+    WRONG_PRICE_PRODUCT_CODES = ["", "en:tomates", "8001505005707XYZ"]
+    for wrong_price_product_code in WRONG_PRICE_PRODUCT_CODES:
+        PRICE_WITH_PRODUCT_CODE_ERROR = PRICE_1.model_copy(
+            update={"product_code": wrong_price_product_code}
+        )
+        response = client.post(
+            "/prices",
+            json=jsonable_encoder(PRICE_WITH_PRODUCT_CODE_ERROR),
+            headers={"Authorization": f"Bearer {user.token}"},
+        )
+        assert response.status_code == 422
+
+
+def test_create_price_category_tag_pattern_validation(user):
+    # category_tag must follow a certain pattern (ex: "en:tomatoes")
+    WRONG_PRICE_CATEGORY_TAGS = ["", ":", "en", ":tomatoes"]
+    for wrong_price_category_tag in WRONG_PRICE_CATEGORY_TAGS:
+        PRICE_WITH_CATEGORY_TAG_ERROR = PRICE_1.model_copy(
+            update={"product_code": None, "category_tag": wrong_price_category_tag}
+        )
+        response = client.post(
+            "/prices",
+            json=jsonable_encoder(PRICE_WITH_CATEGORY_TAG_ERROR),
+            headers={"Authorization": f"Bearer {user.token}"},
+        )
+        assert response.status_code == 422
+
+
+def test_create_price_currency_validation(user):
+    # currency must have a specific format (ex: "EUR")
+    WRONG_PRICE_CURRENCIES = ["", "€", "euro"]
+    for wrong_price_currency in WRONG_PRICE_CURRENCIES:
+        PRICE_WITH_CATEGORY_TAG_ERROR = PRICE_1.model_copy(
+            update={"currency": wrong_price_currency}
+        )
+        response = client.post(
+            "/prices",
+            json=jsonable_encoder(PRICE_WITH_CATEGORY_TAG_ERROR),
+            headers={"Authorization": f"Bearer {user.token}"},
+        )
+        assert response.status_code == 422
+
+
+def test_create_price_code_category_exclusive_validation(user):
+    # both product_code & category_tag missing: error
+    PRICE_WITH_CODE_AND_CATEGORY_MISSING = PRICE_1.model_copy(
+        update={"product_code": None}
+    )
+    response = client.post(
+        "/prices",
+        json=jsonable_encoder(PRICE_WITH_CODE_AND_CATEGORY_MISSING),
+        headers={"Authorization": f"Bearer {user.token}"},
+    )
+    assert response.status_code == 422
+    # only product_code: ok
+    PRICE_WITH_ONLY_PRODUCT_CODE = PRICE_1.model_copy()
+    response = client.post(
+        "/prices",
+        json=jsonable_encoder(PRICE_WITH_ONLY_PRODUCT_CODE),
+        headers={"Authorization": f"Bearer {user.token}"},
+    )
+    assert response.status_code == 200
+    # only category_tag: ok
+    PRICE_WITH_ONLY_CATEGORY = PRICE_1.model_copy(
+        update={"product_code": None, "category_tag": "en:tomatoes"}
+    )
+    response = client.post(
+        "/prices",
+        json=jsonable_encoder(PRICE_WITH_ONLY_CATEGORY),
+        headers={"Authorization": f"Bearer {user.token}"},
+    )
+    assert response.status_code == 200
+    # both product_code & category_tag present: error
+    PRICE_WITH_BOTH_CODE_AND_CATEGORY = PRICE_1.model_copy(
+        update={"category_tag": "en:tomatoes"}
+    )
+    response = client.post(
+        "/prices",
+        json=jsonable_encoder(PRICE_WITH_BOTH_CODE_AND_CATEGORY),
+        headers={"Authorization": f"Bearer {user.token}"},
+    )
+    assert response.status_code == 422
+
+
 def test_get_prices():
     response = client.get("/prices")
     assert response.status_code == 200
-    assert len(response.json()["items"]) == 1
-    for price_field in ["location_id", "proof_id"]:
+    assert len(response.json()["items"]) == 3
+    for price_field in ["product_id", "location_id", "proof_id"]:
         assert price_field in response.json()["items"][0]
 
 
@@ -134,13 +221,13 @@ def test_get_prices_pagination():
 def test_get_prices_filters():
     response = client.get(f"/prices?product_code={PRICE_1.product_code}")
     assert response.status_code == 200
-    assert len(response.json()["items"]) == 1
+    assert len(response.json()["items"]) == 2
     response = client.get("/prices?price__gt=5")
     assert response.status_code == 200
     assert len(response.json()["items"]) == 0
     response = client.get("/prices?date=2023-10-31")
     assert response.status_code == 200
-    assert len(response.json()["items"]) == 1
+    assert len(response.json()["items"]) == 3
 
 
 def test_get_proofs(user):