diff --git a/backend/app/data/build_history.json b/backend/app/data/build_history.json
deleted file mode 100644
index cf07192..0000000
--- a/backend/app/data/build_history.json
+++ /dev/null
@@ -1,44 +0,0 @@
-{
-    "builds": [
-        {
-            "number": 205,
-            "status": "success",
-            "branch": "main",
-            "commit": "9ac3f91",
-            "author": "Miau",
-            "finished_at": "2024-05-04T10:20:00Z",
-            "duration_seconds": 312
-        },
-        {
-            "number": 204,
-            "status": "failed",
-            "branch": "feature/nosetioestoesunmock",
-            "commit": "75c4ba2",
-            "author": "Miau",
-            "finished_at": "2024-05-04T09:50:00Z",
-            "duration_seconds": 188,
-            "failed_stage": "tests",
-            "fun_message": "woops"
-        },
-        {
-            "number": 203,
-            "status": "failed",
-            "branch": "main",
-            "commit": "512ca7e",
-            "author": "Miau",
-            "finished_at": "2024-05-04T09:10:00Z",
-            "duration_seconds": 140,
-            "failed_stage": "lint",
-            "fun_message": "Nadie pasa en local el linter"
-        },
-        {
-            "number": 202,
-            "status": "success",
-            "branch": "hotfix/tehedichoqueestoesunmock?",
-            "commit": "c73d8ab",
-            "author": "Miau",
-            "finished_at": "2024-05-03T18:30:00Z",
-            "duration_seconds": 276
-        }
-    ]
-}
diff --git a/backend/app/main.py b/backend/app/main.py
index 7451365..9aaedb9 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -16,8 +16,10 @@
 
 import time
 
-from fastapi import FastAPI
+import requests
+from fastapi import FastAPI, status
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
 
 from app.services.builds import build_history
 from app.services.menu import build_menu
@@ -76,4 +78,10 @@ def price_for_item(item: str):
 
 @app.get("/builds")
 def builds():
-    return build_history()
+    try:
+        return build_history()
+    except (requests.RequestException, ValueError):
+        return JSONResponse(
+            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
+            content={"builds": [], "error": "jenkins_unavailable"},
+        )
diff --git a/backend/app/services/builds.py b/backend/app/services/builds.py
index d7634b3..27b835d 100644
--- a/backend/app/services/builds.py
+++ b/backend/app/services/builds.py
@@ -15,26 +15,16 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 import base64
-import json
-from pathlib import Path
 from typing import Dict, List
 
 import requests
 
 from app.settings import settings
 
-DATA_DIR = Path(__file__).resolve().parent.parent / "data"
-
-
-def _load_json(filename: str) -> Dict:
-    path = DATA_DIR / filename
-    with open(path, encoding="utf-8") as file:
-        return json.load(file)
-
-
 def _sort_builds(builds: List[Dict]) -> List[Dict]:
     return sorted(builds, key=lambda build: build.get("number", 0), reverse=True)
 
+
 def normalize_build(build: Dict) -> Dict:
     changes = build.get("changeSets", [])
     commits = []
@@ -58,11 +48,16 @@ def normalize_build(build: Dict) -> Dict:
 
 
 def _auth_header() -> Dict[str, str]:
+    if not settings.jenkins_user or not settings.jenkins_token:
+        return {}
     token = f"{settings.jenkins_user}:{settings.jenkins_token}"
     encoded = base64.b64encode(token.encode()).decode()
     return {"Authorization": f"Basic {encoded}"}
 
+
 def fetch_builds(limit: int = 5) -> List[Dict]:
+    if not settings.jenkins_job_name:
+        raise ValueError("JENKINS_JOB_NAME not configured")
     url = (
         f"{settings.jenkins_base_url}/job/{settings.jenkins_job_name}/api/json"
         "?tree=builds[number,url,result,timestamp,duration,"
@@ -78,6 +73,4 @@ def fetch_builds(limit: int = 5) -> List[Dict]:
 def build_history() -> Dict:
     """Return Jenkins build history data."""
     builds = fetch_builds()
-    return {
-        "builds": [normalize_build(b) for b in builds]
-    }
+    return {"builds": [normalize_build(b) for b in builds]}
diff --git a/backend/tests/test_api.py b/backend/tests/test_api.py
index ee9d833..28165b9 100644
--- a/backend/tests/test_api.py
+++ b/backend/tests/test_api.py
@@ -14,6 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+import requests
 from fastapi.testclient import TestClient
 
 from app.main import app
@@ -106,3 +107,16 @@ def test_build_history(monkeypatch):
     assert second["status"] == "running"
     assert second["duration_seconds"] == 1
     assert second["commits"] == []
+
+
+def test_build_history_error_returns_empty(monkeypatch):
+    def raise_error(limit=5):
+        raise requests.RequestException("boom")
+
+    monkeypatch.setattr("app.services.builds.fetch_builds", raise_error)
+
+    response = client.get("/builds")
+    assert response.status_code == 503
+    body = response.json()
+    assert body["builds"] == []
+    assert body["error"] == "jenkins_unavailable"