diff --git a/backend/main.py b/backend/main.py
index 12597af..29489af 100644
--- a/backend/main.py
+++ b/backend/main.py
@@ -1,5 +1,6 @@
 import asyncio
 import json
+import logging
 import sys
 from typing import Any, List, Optional
 
@@ -7,8 +8,23 @@
 from fastapi import FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
 from pydantic import BaseModel
+from utils.cache import (
+    cache_result,
+    github_commits_cache,
+    github_repos_cache,
+    make_github_commits_key,
+    make_github_repos_key,
+    make_social_key,
+    social_cache,
+)
 from utils.security import is_safe_url
 
+logging.basicConfig(
+    level=logging.INFO,
+    format="%(asctime)s [%(name)s] %(levelname)s: %(message)s",
+    datefmt="%H:%M:%S",
+)
+
 # Resilient Windows subprocess execution configuration for asyncio
 if sys.platform == "win32":
     asyncio.set_event_loop_policy(asyncio.WindowsProactorEventLoopPolicy())
@@ -74,13 +90,22 @@ async def handle_scan(request: ScanRequest):
         raise HTTPException(status_code=400, detail="Target cannot be empty.")
 
     if _is_github_input(input_data):
-        git_data: dict | None = await analyze_github_target(input_data)
+        git_data: dict | None = await cache_result(
+            github_repos_cache,
+            make_github_repos_key(input_data),
+            analyze_github_target,
+            input_data,
+        )
 
         if "error" in git_data:
             raise HTTPException(status_code=400, detail=git_data["error"])
 
-        social_result = await scan_username(
-            git_data["username"], include_variations=request.include_variations
+        social_result = await cache_result(
+            social_cache,
+            make_social_key(git_data["username"], request.include_variations),
+            scan_username,
+            git_data["username"],
+            include_variations=request.include_variations,
         )
 
         owner_name = git_data.get("username", "")
@@ -103,8 +128,12 @@ async def handle_scan(request: ScanRequest):
         }
 
     else:
-        social_result = await scan_username(
-            input_data, include_variations=request.include_variations
+        social_result = await cache_result(
+            social_cache,
+            make_social_key(input_data, request.include_variations),
+            scan_username,
+            input_data,
+            include_variations=request.include_variations,
         )
 
         if "error" in social_result:
@@ -121,7 +150,16 @@ async def handle_scan(request: ScanRequest):
         git_data = None
 
         if github_targets:
-            git_tasks = [analyze_github_target(user) for user in github_targets if user]
+            git_tasks = [
+                cache_result(
+                    github_repos_cache,
+                    make_github_repos_key(user),
+                    analyze_github_target,
+                    user,
+                )
+                for user in github_targets
+                if user
+            ]
             git_results = await asyncio.gather(*git_tasks)
 
             aggregated_interesting = []
@@ -190,7 +228,13 @@ async def handle_scan_commits(request: CommitRequest):
             status_code=400, detail="Repository name and username are required."
         )
 
-    result = await fetch_repo_commits(username, repo_name)
+    result = await cache_result(
+        github_commits_cache,
+        make_github_commits_key(username, repo_name),
+        fetch_repo_commits,
+        username,
+        repo_name,
+    )
 
     if "error" in result:
         raise HTTPException(status_code=400, detail=result["error"])
diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index de1bc14..99f3022 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -5,6 +5,7 @@ description = "Add your description here"
 readme = "README.md"
 requires-python = ">=3.13"
 dependencies = [
+    "cachetools>=5.5.0",
     "curl-cffi>=0.15.0",
     "fastapi[standard]>=0.138.0",
     "httpx>=0.28.1",
diff --git a/backend/requirements.txt b/backend/requirements.txt
index c6e1bec..5ff04e1 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -1,3 +1,4 @@
+cachetools>=5.5.0
 fastapi[standard]
 uvicorn
 httpx
diff --git a/backend/utils/cache.py b/backend/utils/cache.py
new file mode 100644
index 0000000..4147a21
--- /dev/null
+++ b/backend/utils/cache.py
@@ -0,0 +1,48 @@
+import logging
+from typing import Any
+
+from cachetools import TTLCache
+
+logger = logging.getLogger(__name__)
+
+SOCIAL_TTL = 600
+REPOS_TTL = 1800
+COMMITS_TTL = 3600
+
+social_cache: TTLCache = TTLCache(maxsize=256, ttl=SOCIAL_TTL)
+github_repos_cache: TTLCache = TTLCache(maxsize=128, ttl=REPOS_TTL)
+github_commits_cache: TTLCache = TTLCache(maxsize=256, ttl=COMMITS_TTL)
+
+
+def make_social_key(username: str, include_variations: bool) -> tuple:
+    return ("social", username, include_variations)
+
+
+def make_github_repos_key(target_input: str) -> tuple:
+    return ("repos", target_input)
+
+
+def make_github_commits_key(username: str, repo_name: str) -> tuple:
+    return ("commits", username, repo_name)
+
+
+async def cache_result(cache: TTLCache, key: tuple, func, *args, **kwargs) -> Any:
+    if key in cache:
+        logger.info("Cache HIT for %s", key)
+        return cache[key]
+
+    result = await func(*args, **kwargs)
+
+    if isinstance(result, dict) and "error" in result:
+        logger.info("Cache MISS for %s (not caching — error response)", key)
+        return result
+
+    cache[key] = result
+    logger.info("Cache MISS for %s", key)
+    return result
+
+
+def clear_all_caches() -> None:
+    social_cache.clear()
+    github_repos_cache.clear()
+    github_commits_cache.clear()
diff --git a/backend/uv.lock b/backend/uv.lock
index 42d0df2..5ad9db3 100644
--- a/backend/uv.lock
+++ b/backend/uv.lock
@@ -41,6 +41,7 @@ name = "backend"
 version = "0.1.0"
 source = { virtual = "." }
 dependencies = [
+    { name = "cachetools" },
     { name = "curl-cffi" },
     { name = "fastapi", extra = ["standard"] },
     { name = "httpx" },
@@ -52,6 +53,7 @@ dependencies = [
 
 [package.metadata]
 requires-dist = [
+    { name = "cachetools", specifier = ">=5.5.0" },
     { name = "curl-cffi", specifier = ">=0.15.0" },
     { name = "fastapi", extras = ["standard"], specifier = ">=0.138.0" },
     { name = "httpx", specifier = ">=0.28.1" },
@@ -61,6 +63,15 @@ requires-dist = [
     { name = "uvicorn", specifier = ">=0.49.0" },
 ]
 
+[[package]]
+name = "cachetools"
+version = "7.1.4"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/f4/8b/0d3945a13955303b81272f759a0331e54c5c793da455e6f5706b89d2639c/cachetools-7.1.4.tar.gz", hash = "sha256:437f55a4e0c1b01a4f3077cc470e6991d47430970e36fbcb77e2be0df4fc1cd6", size = 40085, upload-time = "2026-05-21T22:40:43.376Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/8c/7b/1fc1c09cc0756cf25861a3be10565915953876da48bb228fb9a672b20a42/cachetools-7.1.4-py3-none-any.whl", hash = "sha256:323dc4127934744db5b54eb4924482d7edafbf9554e820d1531c2e08c0e4ef54", size = 16761, upload-time = "2026-05-21T22:40:41.845Z" },
+]
+
 [[package]]
 name = "certifi"
 version = "2026.6.17"