diff --git a/.env_example b/.env_example
index 0f195ff..f2df8f5 100644
--- a/.env_example
+++ b/.env_example
@@ -12,3 +12,5 @@ RAG_USE_REAL_MODELS=0
 # Set to 1 to try loading the MS MARCO dataset from Hugging Face.
 RAG_USE_REAL_DATASET=0
 
+# set the path for metrics
+LOG_PATH=app/logs/metrics.json
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index bfb3e2f..6e99023 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,6 +44,7 @@ coverage.xml
 *.py,cover
 .hypothesis/
 .pytest_cache/
+.pytest_tmp/
 
 # Translations
 *.mo
diff --git a/backend/api/routes.py b/backend/api/routes.py
index 04856ff..2ded301 100644
--- a/backend/api/routes.py
+++ b/backend/api/routes.py
@@ -1,4 +1,5 @@
 import time
+from datetime import datetime, timezone
 from functools import lru_cache
 from typing import Any
 
@@ -7,6 +8,7 @@
 
 from backend.rag.internet_rag import InternetRag
 from backend.rag.neural_rag import NeuralRag
+from backend.utils.logger import log_request
 from backend.utils.metrics import resource_delta, resource_snapshot, timed_call
 
 
@@ -43,6 +45,49 @@ def get_internet_rag() -> InternetRag:
     return InternetRag()
 
 
+def _metric_timestamp() -> str:
+    return datetime.now(timezone.utc).replace(microsecond=0, tzinfo=None).isoformat()
+
+
+def _write_request_metrics(
+    rag_type: str,
+    query: str,
+    metrics: dict[str, float],
+    total_latency: float,
+    resource_before: dict[str, float],
+    resource_after: dict[str, float],
+    status: str = "success",
+) -> None:
+    resources = resource_delta(resource_before, resource_after)
+    log_request(
+        {
+            "timestamp": _metric_timestamp(),
+            "rag_type": rag_type,
+            "query": query,
+            "retrieval_time": metrics.get("retrieval_time", 0.0),
+            "llm_time": metrics.get("llm_time", 0.0),
+            "total_latency": total_latency,
+            "cpu_usage": resources["cpu_percent_avg"],
+            "memory_usage": resources["system_memory_percent_avg"],
+            "status": status,
+        }
+    )
+
+
+def _run_neural_rag(request: QueryRequest) -> RagResponse:
+    rag = get_neural_rag()
+    result, elapsed = timed_call(rag.answer, request.query, k=request.k, answer_len=request.answer_len)
+    result["metrics"]["total_time"] = elapsed
+    return RagResponse(**result)
+
+
+def _run_internet_rag(request: QueryRequest) -> RagResponse:
+    rag = get_internet_rag()
+    result, elapsed = timed_call(rag.answer, request.query, max_results=request.k, answer_len=request.answer_len)
+    result["metrics"]["total_time"] = elapsed
+    return RagResponse(**result)
+
+
 @router.get("/health")
 def health() -> dict[str, str]:
     return {"status": "ok"}
@@ -50,29 +95,73 @@ def health() -> dict[str, str]:
 
 @router.post("/rag/neural", response_model=RagResponse)
 def neural_rag(request: QueryRequest) -> RagResponse:
-    rag = get_neural_rag()
-    result, elapsed = timed_call(rag.answer, request.query, k=request.k, answer_len=request.answer_len)
-    result["metrics"]["total_time"] = elapsed
-    return RagResponse(**result)
+    resource_before = resource_snapshot()
+    try:
+        response = _run_neural_rag(request)
+    except Exception:
+        resource_after = resource_snapshot()
+        _write_request_metrics("neural", request.query, {}, 0.0, resource_before, resource_after, "error")
+        raise
+
+    resource_after = resource_snapshot()
+    _write_request_metrics(
+        "neural",
+        request.query,
+        response.metrics,
+        response.metrics["total_time"],
+        resource_before,
+        resource_after,
+    )
+    return response
 
 
 @router.post("/rag/internet", response_model=RagResponse)
 def internet_rag(request: QueryRequest) -> RagResponse:
-    rag = get_internet_rag()
-    result, elapsed = timed_call(rag.answer, request.query, max_results=request.k, answer_len=request.answer_len)
-    result["metrics"]["total_time"] = elapsed
-    return RagResponse(**result)
+    resource_before = resource_snapshot()
+    try:
+        response = _run_internet_rag(request)
+    except Exception:
+        resource_after = resource_snapshot()
+        _write_request_metrics("internet", request.query, {}, 0.0, resource_before, resource_after, "error")
+        raise
+
+    resource_after = resource_snapshot()
+    _write_request_metrics(
+        "internet",
+        request.query,
+        response.metrics,
+        response.metrics["total_time"],
+        resource_before,
+        resource_after,
+    )
+    return response
 
 
 @router.post("/rag/compare", response_model=CompareResponse)
 def compare_rag(request: QueryRequest) -> CompareResponse:
     resource_before = resource_snapshot()
     elapsed_start = time.time()
-    neural = neural_rag(request)
-    internet = internet_rag(request)
-    total_time = time.time() - elapsed_start
+    try:
+        neural = _run_neural_rag(request)
+        internet = _run_internet_rag(request)
+        total_time = time.time() - elapsed_start
+    except Exception:
+        resource_after = resource_snapshot()
+        _write_request_metrics("compare", request.query, {}, 0.0, resource_before, resource_after, "error")
+        raise
 
     resource_after = resource_snapshot()
     metrics = resource_delta(resource_before, resource_after)
     metrics["total_time"] = total_time
+    _write_request_metrics(
+        "compare",
+        request.query,
+        {
+            "retrieval_time": neural.metrics["retrieval_time"] + internet.metrics["retrieval_time"],
+            "llm_time": neural.metrics["llm_time"] + internet.metrics["llm_time"],
+        },
+        total_time,
+        resource_before,
+        resource_after,
+    )
     return CompareResponse(neural=neural, internet=internet, metrics=metrics)
diff --git a/backend/tests/test_services.py b/backend/tests/test_services.py
index e30ea87..969a450 100644
--- a/backend/tests/test_services.py
+++ b/backend/tests/test_services.py
@@ -1,5 +1,8 @@
-import os
+import json
+from pathlib import Path
+
 import numpy as np
+import pytest
 import requests
 
 from fastapi.testclient import TestClient
@@ -16,6 +19,18 @@
 client = TestClient(app)
 
 
+@pytest.fixture(autouse=True)
+def metrics_log_path(monkeypatch, tmp_path):
+    log_path = tmp_path / "logs" / "metrics.json"
+    log_path.parent.mkdir(parents=True, exist_ok=True)
+    monkeypatch.setattr("backend.utils.logger.LOG_PATH", str(log_path))
+    return log_path
+
+
+def read_metric_lines(path):
+    return [json.loads(line) for line in Path(path).read_text().splitlines()]
+
+
 def test_neural_rag_smoke():
     result = NeuralRag().answer("What is machine learning?", k=2)
     assert result["method"] == "neural"
@@ -132,6 +147,34 @@ def test_neural_endpoint():
     assert body["contexts"]
     assert {"retrieval_time", "llm_time", "context_size", "total_time"} <= set(body["metrics"])
 
+
+def test_neural_endpoint_writes_request_metrics(monkeypatch, tmp_path):
+    log_path = tmp_path / "logs" / "metrics.json"
+    monkeypatch.setattr("backend.utils.logger.LOG_PATH", str(log_path))
+
+    response = client.post("/api/rag/neural", json={"query": "What is machine learning?", "k": 2})
+
+    assert response.status_code == 200
+    metrics = read_metric_lines(log_path)
+    assert len(metrics) == 1
+    assert {
+        "timestamp",
+        "rag_type",
+        "query",
+        "retrieval_time",
+        "llm_time",
+        "total_latency",
+        "cpu_usage",
+        "memory_usage",
+        "status",
+    } <= set(metrics[0])
+    assert metrics[0]["rag_type"] == "neural"
+    assert metrics[0]["query"] == "What is machine learning?"
+    assert metrics[0]["status"] == "success"
+    assert metrics[0]["retrieval_time"] >= 0
+    assert metrics[0]["llm_time"] >= 0
+    assert metrics[0]["total_latency"] >= 0
+
 # Test that the internet endpoint returns an answer and contexts with metrics
 def test_internet_endpoint():
     response = client.post("/api/rag/internet", json={"query": "What is machine learning?", "k": 2})
@@ -142,6 +185,23 @@ def test_internet_endpoint():
     assert body["contexts"]
     assert {"retrieval_time", "llm_time", "context_size", "total_time"} <= set(body["metrics"])
 
+
+def test_internet_endpoint_writes_request_metrics(monkeypatch, tmp_path):
+    log_path = tmp_path / "logs" / "metrics.json"
+    monkeypatch.setattr("backend.utils.logger.LOG_PATH", str(log_path))
+
+    response = client.post("/api/rag/internet", json={"query": "What is machine learning?", "k": 2})
+
+    assert response.status_code == 200
+    metrics = read_metric_lines(log_path)
+    assert len(metrics) == 1
+    assert metrics[0]["rag_type"] == "internet"
+    assert metrics[0]["query"] == "What is machine learning?"
+    assert metrics[0]["status"] == "success"
+    assert metrics[0]["retrieval_time"] >= 0
+    assert metrics[0]["llm_time"] >= 0
+    assert metrics[0]["total_latency"] >= 0
+
 # Test that the compare endpoint returns both neural and internet results with metrics
 def test_compare_endpoint_includes_resource_metrics():
     response = client.post("/api/rag/compare", json={"query": "What is machine learning?", "k": 2})
@@ -153,6 +213,23 @@ def test_compare_endpoint_includes_resource_metrics():
     assert "memory_rss_mb_after" in body["metrics"]
     assert "system_memory_percent_avg" in body["metrics"]
 
+
+def test_compare_endpoint_writes_single_request_metrics(monkeypatch, tmp_path):
+    log_path = tmp_path / "logs" / "metrics.json"
+    monkeypatch.setattr("backend.utils.logger.LOG_PATH", str(log_path))
+
+    response = client.post("/api/rag/compare", json={"query": "What is machine learning?", "k": 2})
+
+    assert response.status_code == 200
+    metrics = read_metric_lines(log_path)
+    assert len(metrics) == 1
+    assert metrics[0]["rag_type"] == "compare"
+    assert metrics[0]["query"] == "What is machine learning?"
+    assert metrics[0]["status"] == "success"
+    assert metrics[0]["retrieval_time"] >= 0
+    assert metrics[0]["llm_time"] >= 0
+    assert metrics[0]["total_latency"] >= 0
+
 # Additional tests for query validation and edge cases 
 def test_query_validation():
     response = client.post("/api/rag/neural", json={"query": "", "k": 2})
diff --git a/backend/utils/logger.py b/backend/utils/logger.py
index e424b17..49e549e 100644
--- a/backend/utils/logger.py
+++ b/backend/utils/logger.py
@@ -1,6 +1,24 @@
+import json
 import logging
 import os
 from pathlib import Path
+import json
+from datetime import datetime
+
+
+BASE_DIR = Path(__file__).resolve().parent.parent.parent
+LOG_DIR = BASE_DIR / "logs"
+LOG_DIR.mkdir(parents=True, exist_ok=True)
+
+LOG_PATH = LOG_DIR / "metrics.json"
+
+
+def log_request(data: dict):
+    with open(LOG_PATH, "a") as f:
+        f.write(json.dumps({
+            "timestamp": datetime.utcnow().isoformat(),
+            **data
+        }) + "\n")
 
 
 # Utility functions for environment variable loading and logging setup
diff --git a/conftest.py b/conftest.py
new file mode 100644
index 0000000..e642bb6
--- /dev/null
+++ b/conftest.py
@@ -0,0 +1,29 @@
+"""Project-wide pytest configuration.
+
+Two things this file handles before any test runs:
+
+* Force the offline / deterministic code paths for the RAG services so tests do
+  not download models, stream datasets, or call external APIs. Backend modules
+  call ``load_project_env()`` at import time which reads ``.env`` only for keys
+  that are NOT already set, so these assignments must happen before any
+  ``backend.*`` module is imported.
+* Pin pytest's ``basetemp`` to a workspace-local folder. The default Windows
+  temp directory is locked on some workstations, which makes ``tmp_path`` raise
+  ``PermissionError`` during fixture setup.
+"""
+
+import os
+from pathlib import Path
+
+
+os.environ["RAG_USE_REAL_MODELS"] = "0"
+os.environ["RAG_USE_REAL_DATASET"] = "0"
+os.environ["TAVILY_API_KEY"] = ""
+
+
+ROOT = Path(__file__).resolve().parent
+
+
+def pytest_configure(config):
+    if not config.option.basetemp:
+        config.option.basetemp = str(ROOT / ".pytest_tmp")
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 0980e1d..02f537a 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -15,6 +15,12 @@ RUN useradd --create-home --shell /usr/sbin/nologin appuser
 
 COPY --chown=appuser:appuser backend ./backend
 
+# Create writable logs directory
+RUN mkdir -p /app/logs
+
+# Give ownership to appuser
+RUN chown -R appuser:appuser /app
+
 USER appuser
 
 EXPOSE 8000
diff --git a/requirements.txt b/requirements.txt
index 4a4fba8..ccf6119 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,5 @@ numpy>=2.0.0
 psutil>=7.0.0
 requests>=2.32.0
 beautifulsoup4>=4.12.0
+pytest>=7.0.0
+pytest-asyncio>=0.20.0
\ No newline at end of file