diff --git a/api/hearts/hearts_views.py b/api/hearts/hearts_views.py
index ca827e8..4b994aa 100644
--- a/api/hearts/hearts_views.py
+++ b/api/hearts/hearts_views.py
@@ -17,6 +17,14 @@
 bp = Blueprint(bp_name, __name__, url_prefix=bp_url_prefix)
 
 
+@bp.route("/hearts/leaderboard", methods=["GET"])
+def get_hearts_leaderboard():
+    limit = request.args.get("limit", 10, type=int)
+    limit = min(max(limit, 1), 50)
+    res = hearts_service.get_hearts_leaderboard(limit)
+    return {"leaderboard": res}
+
+
 # Used to provide profile details - user must be logged in
 @bp.route("/hearts", methods=["GET"])
 @auth.require_user
diff --git a/services/hearts_service.py b/services/hearts_service.py
index 93edd7c..b9fc1fc 100644
--- a/services/hearts_service.py
+++ b/services/hearts_service.py
@@ -65,6 +65,31 @@ def get_hearts_for_all_users():
     return result
 
 
+def get_hearts_leaderboard(limit: int = 10) -> list:
+    users = fetch_users()
+    result = []
+
+    for user in users:
+        total_hearts = 0
+
+        if user.history:
+            for key in user.history:
+                if "certificates" in key:
+                    continue
+                for subkey in user.history[key]:
+                    total_hearts += user.history[key][subkey]
+
+        if total_hearts > 0:
+            result.append({
+                "name": user.name,
+                "totalHearts": total_hearts,
+                "userId": user.id,
+                "profileImage": user.profile_image,
+            })
+
+    result.sort(key=lambda x: x["totalHearts"], reverse=True)
+    return result[:limit]
+
 
 
 def save_hearts(user_id, hearts_json):
diff --git a/test/services/test_hearts_service.py b/test/services/test_hearts_service.py
new file mode 100644
index 0000000..f2819da
--- /dev/null
+++ b/test/services/test_hearts_service.py
@@ -0,0 +1,86 @@
+import sys
+from types import ModuleType
+from unittest.mock import MagicMock, patch
+
+# Pre-mock all problematic modules before any imports
+_mock_modules = [
+    "db.db", "db.firestore", "db.mem", "db.interface",
+    "google.cloud", "google.cloud.storage", "google.cloud.firestore",
+    "common.utils.firebase", "common.utils.slack", "common.utils.cdn",
+    "openai", "PIL", "PIL.ImageFont", "PIL.ImageDraw", "PIL.Image",
+    "PIL.ImageEnhance",
+]
+for mod_name in _mock_modules:
+    if mod_name not in sys.modules:
+        sys.modules[mod_name] = MagicMock()
+
+# Now safe to import
+from services.hearts_service import get_hearts_leaderboard
+
+
+def _make_user(name, user_id, profile_image, history):
+    user = MagicMock()
+    user.name = name
+    user.id = user_id
+    user.profile_image = profile_image
+    user.history = history
+    return user
+
+
+USERS = [
+    _make_user("Alice", "u1", "img1.png", {
+        "how": {"code_reliability": 3, "standups_completed": 2},
+        "what": {"documentation": 1},
+    }),
+    _make_user("Bob", "u2", "img2.png", {
+        "how": {"code_reliability": 1},
+        "what": {"documentation": 0.5},
+    }),
+    _make_user("Carol", "u3", "img3.png", {
+        "how": {"code_reliability": 0},
+        "what": {"documentation": 0},
+    }),
+    _make_user("Dave", "u4", "img4.png", {
+        "how": {"code_reliability": 10},
+        "what": {"unit_test_writing": 5},
+        "certificates": ["cert1.png"],
+    }),
+    _make_user("Eve", "u5", None, {}),
+]
+
+
+@patch("services.hearts_service.fetch_users", return_value=USERS)
+def test_sort_order_descending(mock_fetch):
+    result = get_hearts_leaderboard(limit=50)
+    hearts = [entry["totalHearts"] for entry in result]
+    assert hearts == sorted(hearts, reverse=True)
+
+
+@patch("services.hearts_service.fetch_users", return_value=USERS)
+def test_zero_hearts_excluded(mock_fetch):
+    result = get_hearts_leaderboard(limit=50)
+    names = [entry["name"] for entry in result]
+    assert "Carol" not in names
+    assert "Eve" not in names
+
+
+@patch("services.hearts_service.fetch_users", return_value=USERS)
+def test_certificates_excluded_from_count(mock_fetch):
+    result = get_hearts_leaderboard(limit=50)
+    dave = next(e for e in result if e["name"] == "Dave")
+    # Only how + what should count: 10 + 5 = 15, not certificates
+    assert dave["totalHearts"] == 15
+
+
+@patch("services.hearts_service.fetch_users", return_value=USERS)
+def test_limit_respected(mock_fetch):
+    result = get_hearts_leaderboard(limit=2)
+    assert len(result) == 2
+
+
+@patch("services.hearts_service.fetch_users", return_value=USERS)
+def test_correct_return_fields(mock_fetch):
+    result = get_hearts_leaderboard(limit=50)
+    expected_keys = {"name", "totalHearts", "userId", "profileImage"}
+    for entry in result:
+        assert set(entry.keys()) == expected_keys