diff --git a/backend/app/app/source/AAAI.py b/backend/app/app/source/AAAI.py
index 74ba44c..0a5cf6d 100644
--- a/backend/app/app/source/AAAI.py
+++ b/backend/app/app/source/AAAI.py
@@ -2,7 +2,7 @@
 
 from scrapy.http import HtmlResponse
 
-from app.source.base import PaperRequestsTask
+from app.source.base import PaperRequestsTask, PaperType
 
 import xml.dom.minidom
 
@@ -43,7 +43,7 @@ def parse(response: HtmlResponse):
         return item
 
     @staticmethod
-    def post_parse(item: dict[str, Any]) -> dict[str, Any]:
+    def post_parse(item: PaperType) -> PaperType:
         if item["authors"] is not None:
             for i, author in enumerate(item["authors"]):
                 item["authors"][i] = author.strip()
diff --git a/backend/app/app/source/Arxiv.py b/backend/app/app/source/Arxiv.py
index adb9246..223fd50 100644
--- a/backend/app/app/source/Arxiv.py
+++ b/backend/app/app/source/Arxiv.py
@@ -3,7 +3,7 @@
 
 from scrapy.http import HtmlResponse
 
-from app.source.base import RSSTask
+from app.source.base import PaperType, RSSTask
 
 CATEGORY_MAP = {
     "cs.AI": "Artificial Intelligence",
@@ -48,7 +48,7 @@ def parse(entry: dict) -> dict[str, Any]:
             "abstract": entry["summary"],
         }
 
-    def post_parse(self, entry: dict[str, Any]) -> dict[str, Any]:
+    def post_parse(self, entry: PaperType) -> PaperType:
         category = re.findall(r"\[(.*?)\]", entry["title"])[0]
         entry["title"] = entry["title"].split("(", 1)[0]
         entry["authors"] = (
diff --git a/backend/app/app/source/NIPS.py b/backend/app/app/source/NIPS.py
index d6f4f7b..918407e 100644
--- a/backend/app/app/source/NIPS.py
+++ b/backend/app/app/source/NIPS.py
@@ -2,7 +2,7 @@
 
 from scrapy.http import HtmlResponse
 
-from app.source.base import PaperRequestsTask, openreview_url
+from app.source.base import PaperRequestsTask, PaperType, openreview_url
 
 
 class NIPS(PaperRequestsTask):
@@ -34,9 +34,9 @@ def parse(response: HtmlResponse):
         return item
 
     @staticmethod
-    def post_parse(item: dict[str, Any]) -> dict[str, Any]:
+    def post_parse(item: PaperType) -> PaperType:
         if item["authors"] is not None:
-            item["authors"] = item["authors"].split(" · ")
+            item["authors"] = item["authors"].split(" · ")  # type: ignore
         if item["authors"] is not None:
             for i, author in enumerate(item["authors"]):
                 item["authors"][i] = author.strip()
diff --git a/backend/app/app/source/base.py b/backend/app/app/source/base.py
index fb535a4..f822ccb 100644
--- a/backend/app/app/source/base.py
+++ b/backend/app/app/source/base.py
@@ -1,6 +1,6 @@
 import logging
 from datetime import datetime
-from typing import Any
+from typing import Any, Optional, TypedDict
 
 import feedparser
 import requests
@@ -12,6 +12,15 @@
 from app.models import CrawledItem, Item
 
 
+class PaperType(TypedDict):
+    title: str
+    abstract: Optional[str]
+    url: str
+    authors: Optional[list[str]]
+    category: Optional[list[str]]
+    keywords: Optional[list[str]]
+
+
 def openreview_url(urls):
     for url in urls[::-1]:
         if "openreview" in url:
@@ -46,7 +55,7 @@ def get_urls(cls) -> list[str]:
         return cls.parse_urls(response)
 
     @staticmethod
-    def parse(response: HtmlResponse) -> dict[str, str]:
+    def parse(response: HtmlResponse) -> PaperType:
         # you should return dict with fields:
         # title, abstract, url
         raise NotImplementedError
@@ -81,7 +90,7 @@ def save(self, data: list[tuple[str, dict[str, Any]]]) -> None:
             db.commit()
 
     @staticmethod
-    def post_parse(data: dict[str, Any]) -> dict[str, Any]:
+    def post_parse(data: PaperType) -> PaperType:
         # you can do some post processing here
         return data
 
@@ -118,13 +127,13 @@ def db(self):
         return Session(engine)
 
     @staticmethod
-    def parse(entry) -> dict[str, Any]:
+    def parse(entry) -> PaperType:
         raise NotImplementedError
 
-    def post_parse(self, entry: dict[str, Any]) -> dict[str, Any]:
+    def post_parse(self, entry: PaperType) -> PaperType:
         return entry
 
-    def save(self, data: list[dict[str, Any]]) -> None:
+    def save(self, data: list[PaperType]) -> None:
         with self.db as db:
             # update Item table if exists
             for item in data: