diff --git a/web/tests/test_content.py b/web/tests/test_content.py
index 015b3ff..4e5cbcf 100644
--- a/web/tests/test_content.py
+++ b/web/tests/test_content.py
@@ -9,6 +9,8 @@ import importlib
 import json
 import sqlite3
 from datetime import date, datetime
+
+from padelnomics.core import utcnow_iso
 from pathlib import Path
 
 import pytest
@@ -70,7 +72,7 @@ async def _create_published_scenario(slug="test-scenario", city="TestCity", coun
 async def _create_article(slug="test-article", url_path="/test-article",
                            status="published", published_at=None):
     """Insert an article row, return its id."""
-    pub = published_at or datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")
+    pub = published_at or utcnow_iso()
     return await execute(
         """INSERT INTO articles
            (url_path, slug, title, meta_description, country, region,
@@ -936,8 +938,7 @@ class TestRouteRegistration:
 @pytest.fixture
 async def admin_client(app, db):
     """Test client with admin user (has admin role)."""
-    from datetime import datetime
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         "INSERT INTO users (email, name, created_at) VALUES (?, ?, ?)",
         ("admin@test.com", "Admin", now),
diff --git a/web/tests/test_credits.py b/web/tests/test_credits.py
index 054dfbe..5599a7c 100644
--- a/web/tests/test_credits.py
+++ b/web/tests/test_credits.py
@@ -3,7 +3,7 @@ Tests for the credit system (credits.py).
 
 Pure SQL operations against real in-memory SQLite — no mocking needed.
 """
-from datetime import datetime
+from padelnomics.core import utcnow_iso
 
 import pytest
 from padelnomics.credits import (
@@ -24,7 +24,7 @@ from padelnomics.credits import (
 @pytest.fixture
 async def supplier(db):
     """Supplier with credit_balance=100, monthly_credits=30, tier=growth."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         """INSERT INTO suppliers
            (name, slug, country_code, region, category, tier,
@@ -41,7 +41,7 @@ async def supplier(db):
 @pytest.fixture
 async def lead(db):
     """Lead request with heat_score=warm, credit_cost=20."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         """INSERT INTO lead_requests
            (lead_type, heat_score, credit_cost, status, created_at)
@@ -154,7 +154,7 @@ class TestAlreadyUnlocked:
         assert await already_unlocked(supplier["id"], lead["id"]) is False
 
     async def test_returns_true_after_unlock(self, db, supplier, lead):
-        now = datetime.utcnow().isoformat()
+        now = utcnow_iso()
         await db.execute(
             """INSERT INTO lead_forwards (lead_id, supplier_id, credit_cost, created_at)
                VALUES (?, ?, 20, ?)""",
@@ -210,7 +210,7 @@ class TestUnlockLead:
 
     async def test_raises_insufficient_credits(self, db, lead):
         """Supplier with only 5 credits tries to unlock a 20-credit lead."""
-        now = datetime.utcnow().isoformat()
+        now = utcnow_iso()
         async with db.execute(
             """INSERT INTO suppliers
                (name, slug, country_code, region, category, tier,
@@ -247,7 +247,7 @@ class TestMonthlyRefill:
 
     async def test_noop_when_no_monthly_credits(self, db):
         """Supplier with monthly_credits=0 gets no refill."""
-        now = datetime.utcnow().isoformat()
+        now = utcnow_iso()
         async with db.execute(
             """INSERT INTO suppliers
                (name, slug, country_code, region, category, tier,
diff --git a/web/tests/test_feature_flags.py b/web/tests/test_feature_flags.py
index 4ab8768..b467c6b 100644
--- a/web/tests/test_feature_flags.py
+++ b/web/tests/test_feature_flags.py
@@ -7,7 +7,8 @@ Integration tests exercise full request/response flows via Quart test client.
 """
 
 import sqlite3
-from datetime import datetime
+
+from padelnomics.core import utcnow_iso
 from pathlib import Path
 from unittest.mock import AsyncMock, patch
 
@@ -30,7 +31,7 @@ def mock_csrf_validation():
 @pytest.fixture
 async def admin_client(app, db):
     """Test client with an admin-role user session (module-level, follows test_content.py)."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         "INSERT INTO users (email, name, created_at) VALUES (?, ?, ?)",
         ("flags_admin@test.com", "Flags Admin", now),
diff --git a/web/tests/test_seo.py b/web/tests/test_seo.py
index 708ee51..64dc5b6 100644
--- a/web/tests/test_seo.py
+++ b/web/tests/test_seo.py
@@ -1,6 +1,8 @@
 """Tests for the SEO metrics module: queries, sync functions, admin routes."""
 
-from datetime import datetime, timedelta
+from datetime import UTC, datetime, timedelta
+
+from padelnomics.core import utcnow_iso
 from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
@@ -21,11 +23,11 @@ from padelnomics import core
 # ── Fixtures ──────────────────────────────────────────────────
 
 def _today():
-    return datetime.utcnow().strftime("%Y-%m-%d")
+    return datetime.now(UTC).strftime("%Y-%m-%d")
 
 
 def _days_ago(n: int) -> str:
-    return (datetime.utcnow() - timedelta(days=n)).strftime("%Y-%m-%d")
+    return (datetime.now(UTC) - timedelta(days=n)).strftime("%Y-%m-%d")
 
 
 @pytest.fixture
@@ -72,7 +74,7 @@ async def seo_data(db):
 @pytest.fixture
 async def articles_data(db, seo_data):
     """Create articles that match the SEO data URLs."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     pub = _days_ago(10)
 
     for title, url, tpl, lang in [
@@ -91,7 +93,7 @@ async def articles_data(db, seo_data):
 @pytest.fixture
 async def admin_client(app, db):
     """Authenticated admin client."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         "INSERT INTO users (email, name, created_at) VALUES (?, ?, ?)",
         ("admin@test.com", "Admin", now),
@@ -258,7 +260,7 @@ class TestSyncStatus:
     """Tests for get_sync_status()."""
 
     async def test_returns_last_sync_per_source(self, db):
-        now = datetime.utcnow().isoformat()
+        now = utcnow_iso()
         await db.execute(
             """INSERT INTO seo_sync_log (source, status, rows_synced, started_at, completed_at, duration_ms)
                VALUES ('gsc', 'success', 100, ?, ?, 500)""",
@@ -286,7 +288,7 @@ class TestCleanupOldMetrics:
     """Tests for cleanup_old_metrics()."""
 
     async def test_deletes_old_data(self, db):
-        old_date = (datetime.utcnow() - timedelta(days=400)).strftime("%Y-%m-%d")
+        old_date = (datetime.now(UTC) - timedelta(days=400)).strftime("%Y-%m-%d")
         recent_date = _today()
 
         await db.execute(
diff --git a/web/tests/test_supplier_webhooks.py b/web/tests/test_supplier_webhooks.py
index 2eba57c..2f1d1da 100644
--- a/web/tests/test_supplier_webhooks.py
+++ b/web/tests/test_supplier_webhooks.py
@@ -5,7 +5,9 @@ POST real webhook payloads to /billing/webhook/paddle and verify DB state.
 Uses the existing client, db, sign_payload from conftest.
 """
 import json
-from datetime import datetime
+from datetime import UTC, datetime
+
+from padelnomics.core import utcnow_iso
 from unittest.mock import AsyncMock, patch
 
 import pytest
@@ -21,7 +23,7 @@ SIG_HEADER = "Paddle-Signature"
 @pytest.fixture
 async def supplier(db):
     """Supplier with tier=free, credit_balance=0."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     async with db.execute(
         """INSERT INTO suppliers
            (name, slug, country_code, region, category, tier,
@@ -38,7 +40,7 @@ async def supplier(db):
 @pytest.fixture
 async def paddle_products(db):
     """Insert paddle_products rows for all keys the handlers need."""
-    now = datetime.utcnow().isoformat()
+    now = utcnow_iso()
     products = [
         ("credits_25", "pri_credits25", "Credit Pack 25", 999, "one_time"),
         ("credits_100", "pri_credits100", "Credit Pack 100", 3290, "one_time"),
@@ -175,7 +177,7 @@ class TestStickyBoostPurchase:
         assert boosts[0][1] == "active"
         # expires_at should be ~7 days from now
         expires = datetime.fromisoformat(boosts[0][2])
-        assert abs((expires - datetime.utcnow()).days - 7) <= 1
+        assert abs((expires - datetime.now(UTC).replace(tzinfo=None)).days - 7) <= 1
 
         # Verify sticky_until set on supplier
         sup = await db.execute_fetchall(
@@ -202,7 +204,7 @@ class TestStickyBoostPurchase:
         assert len(boosts) == 1
         assert boosts[0][0] == "sticky_month"
         expires = datetime.fromisoformat(boosts[0][1])
-        assert abs((expires - datetime.utcnow()).days - 30) <= 1
+        assert abs((expires - datetime.now(UTC).replace(tzinfo=None)).days - 30) <= 1
 
     async def test_sticky_boost_sets_country(self, client, db, supplier, paddle_products):
         payload = make_transaction_payload(
@@ -387,7 +389,7 @@ class TestBusinessPlanPurchase:
         self, client, db, supplier, paddle_products, test_user,
     ):
         # Need a scenario for the export
-        now = datetime.utcnow().isoformat()
+        now = utcnow_iso()
         async with db.execute(
             """INSERT INTO scenarios (user_id, name, state_json, created_at)
                VALUES (?, 'Test Scenario', '{}', ?)""",