diff --git a/README.md b/README.md
index 57ffe15..f41b50e 100644
--- a/README.md
+++ b/README.md
@@ -4,3 +4,10 @@ This tool uses the [PDAP API](https://docs.pdap.io/api/endpoints/data-sources-da
 Then, it uses the PDAP API to update the Data Sources' `last_cached` and `url_status` properties.
 
 The script is set up to run with a GitHub Actions workflow.
+
+Requires the following environment variables to be set:
+
+```text
+VUE_APP_PDAP_API_KEY=<YOUR_PDAP_API_KEY>
+VITE_VUE_APP_BASE_URL=<YOUR_PDAP_API_URL>
+```
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diff --git a/cache_url.py b/cache_url.py
index 44c4336..5d82c2f 100644
--- a/cache_url.py
+++ b/cache_url.py
@@ -1,11 +1,32 @@
 import json
 from datetime import datetime, timedelta
-from concurrent.futures import as_completed, ThreadPoolExecutor
+from dataclasses import dataclass
 from tqdm import tqdm
 import requests
 import os
 import time
 
+# How long to wait in between archive requests, in seconds
+# Too many requests will result in the IP being temporarily blocked: https://archive.org/details/toomanyrequests_20191110
+ARCHIVE_WAIT_TIME = 7
+
+class ArchiveLastCacheNotFoundError(Exception):
+    pass
+
+
+@dataclass
+class ArchiveEntry:
+    url: str
+    last_archived: datetime
+    broken_source_url_as_of: datetime | None
+    source_url: str
+    update_delta: timedelta
+
+    @classmethod
+    def from_dict(cls, dict_entry: dict):
+        return cls(**dict_entry)
+
+
 API_KEY = "Bearer " + os.getenv("VUE_APP_PDAP_API_KEY")
 UPDATE_FREQUENCY_MAPPING = {
     "Incident-based": 7,
@@ -24,113 +45,183 @@
 }
 
 
-def cache_url(entry):
+def archive_url(entry: dict):
+    """
+
+    :param entry:
+    :return:
+    """
     entry["broken_source_url_as_of"] = None
     source_url = entry.get("source_url")
-    if source_url is None:
-        entry["broken_source_url_as_of"] = datetime.now().strftime("%Y-%m-%d")
-        # try:
-        entry_json = json.dumps(entry)
-        requests.put(
-            f"{os.getenv('VITE_VUE_APP_BASE_URL')}/archives",
-            json=entry_json,
-            headers={"Authorization": API_KEY},
-        )
-        raise Exception("No source_url")
-        # except Exception as error:
-        #     print(str(error))
-        # exceptions.append({
-        #                 "source_url": source_url,
-        #                 "exception": str(error)})
-
-    update_delta = (
-        UPDATE_FREQUENCY_MAPPING[entry.get("update_frequency")]
-        if entry.get("update_frequency") is not None
-        else None
-    )
-    if update_delta is None:
-        update_delta = datetime.max - datetime.today()
-    else:
-        update_delta = timedelta(days=int(update_delta))
-
-    last_cached = entry.get("last_cached")
-    if last_cached is not None:
-        last_cached = datetime.strptime(last_cached, "%Y-%m-%d")
-    else:
-        # Check if website exists in archive and compare archived website to current site
-        last_cached = datetime.min
-        website_info_data = None
-        try:
-            website_info = requests.get(
-                f"https://archive.org/wayback/available?url={source_url}"
-            )
-            website_info_data = website_info.json()
-            if website_info_data["archived_snapshots"]:
-                website_info_data_last_cached = datetime.strptime(
-                    website_info_data["archived_snapshots"]["closest"]["timestamp"],
-                    "%Y%m%d%H%M%S",
-                )
-                if website_info_data_last_cached > last_cached:
-                    last_cached = website_info_data_last_cached
-        except Exception as error:
-            # print(str(error))
-            website_info_data = {"archived_snapshots": None}
 
-    # Cache if never cached or more than update_delta days have passed since last_cache
-    if last_cached + update_delta < datetime.today():
+    try:
+        wait_then_post(entry, source_url, ARCHIVE_WAIT_TIME)
+    except Exception as error:
         try:
-            time.sleep(1)
-            api_url = f"http://web.archive.org/save/{source_url}"
-            requests.post(api_url)
-            # Update the last_cached date if cache is successful
-            entry["last_cached"] = datetime.now().strftime("%Y-%m-%d")
+            wait_then_post(entry, source_url, 10)
         except Exception as error:
-            try:
-                time.sleep(3)
-                requests.post(api_url)
-                # Update the last_cached date if cache is successful
-                entry["last_cached"] = datetime.now().strftime("%Y-%m-%d")
-            except:
-                print(str(error))
-            # exceptions.append({
-            #                 "source_url": source_url,
-            #                 "exception": str(error)})
-    else:
-        entry["last_cached"] = last_cached.strftime("%Y-%m-%d")
-
+            print(str(error))
     # Send updated data to Data Sources
+    update_pdap_archives(entry)
+
+def wait_then_post(entry: dict, source_url: str, wait_time: int):
+    """
+    Wait then post to Internet Archive
+    :param entry:
+    :param source_url:
+    :param wait_time: The amount of time to wait
+    :return:
+    """
+    api_url = f"http://web.archive.org/save/{source_url}"
+    time.sleep(wait_time)
+    requests.post(api_url)
+    # Update the last_cached date if cache is successful
+    entry["last_cached"] = datetime.now().strftime("%Y-%m-%d")
+
+
+def handle_missing_source_url(entry: dict):
+    """
+    Record when url was found to be missing,
+    update PDAP archives, and throw exception
+    :param entry:
+    :return:
+    """
+    entry["broken_source_url_as_of"] = datetime.now().strftime("%Y-%m-%d")
+    update_pdap_archives(entry)
+    raise Exception("No source_url")
+
+
+def update_pdap_archives(entry: dict):
+    """
+    Update data in PDAP archives
+    :param entry:
+    :return:
+    """
     entry_json = json.dumps(entry)
-    requests.put(
+    response = requests.put(
         f"{os.getenv('VITE_VUE_APP_BASE_URL')}/archives",
         json=entry_json,
         headers={"Authorization": API_KEY},
     )
+    response.raise_for_status()
+
+
+
+def get_update_delta(update_frequency: str | None) -> timedelta:
+    """
+    Calculate update delt based on entry's update frequency
+    :param entry:
+    :return:
+    """
+    try:
+        update_delta = UPDATE_FREQUENCY_MAPPING[update_frequency]
+    except KeyError:
+        return datetime.max - datetime.today()
+    if update_delta is None:
+        return datetime.max - datetime.today()
+    return timedelta(days=int(update_delta))
+
+
+def get_website_info_data_last_cached(source_url) -> datetime:
+    website_info_data = get_website_info_data(source_url)
+    if not website_info_data["archived_snapshots"]:
+        raise ArchiveLastCacheNotFoundError
+    return datetime.strptime(
+        website_info_data["archived_snapshots"]["closest"]["timestamp"],
+        "%Y%m%d%H%M%S",
+    )
+
+
+def get_last_archived(last_archived: str | None, source_url: str) -> datetime:
+    """
+    Get last archived date of website from Internet Archive.
+    :param entry:
+    :param source_url:
+    :return:
+    """
+    if last_archived is not None:
+        try:
+            return datetime.strptime(last_archived, "%Y-%m-%d")
+        except ValueError:
+            return datetime.min
+    # Check if website exists in archive and compare archived website to current site
+    last_archived = datetime.min
+    try:
+        website_info_data_last_cached = get_website_info_data_last_cached(source_url)
+    except ArchiveLastCacheNotFoundError:
+        return last_archived
+    if website_info_data_last_cached > last_archived:
+        return website_info_data_last_cached
+    return last_archived
+
+
+def get_website_info_data(source_url):
+    website_info = requests.get(
+        f"https://archive.org/wayback/available?url={source_url}"
+    )
+    website_info_data = website_info.json()
+    return website_info_data
 
 
 def main():
+    data = get_from_archives()
+    extract_url_info_and_archived_if_needed(data)
+
+
+def extract_url_info_and_archived_if_needed(data: list[dict]):
+    """
+
+    :param data:
+    :return:
+    """
+    # Create a tuple of entries with missing source URLs
+    missing_source_url_entries = tuple(filter(missing_source_url, data))
+
+    # Handle entries with missing source URLs
+    print("Handling missing source urls")
+    for entry in tqdm(missing_source_url_entries):
+        handle_missing_source_url(entry)
+
+    print("\nFinding entries that need updates")
+    non_missing_source_url_entries = tuple(filter(lambda e: not missing_source_url(e), data))
+    entries_needing_updates = []
+    for entry in tqdm(non_missing_source_url_entries):
+        if needs_updated(entry):
+            entries_needing_updates.append(entry)
+
+    print(f"Updating {len(entries_needing_updates)} entries that need updates")
+    # Handle entries that need to be updated
+    for entry in tqdm(entries_needing_updates):
+        try:
+            archive_url(entry)
+        except Exception as error:
+            print(str(error))
+
+def missing_source_url(entry: dict):
+    return entry['source_url'] is None
+
+def needs_updated(entry: dict) -> bool:
+    """
+    Check if entry needs to be updated
+    :param entry:
+    :return:
+    """
+    last_archived = get_last_archived(entry["last_cached"], entry["source_url"])
+    update_delta = get_update_delta(entry["update_frequency"])
+    return last_archived + update_delta < datetime.now()
+
+def get_from_archives() -> list[dict]:
+    """
+    Get data from PDAP Archive.
+    :param url:
+    :return:
+    """
     response = requests.get(
         f"{os.getenv('VITE_VUE_APP_BASE_URL')}/archives",
         headers={"Authorization": API_KEY},
     )
-    data = response.json()
-
-    # Extract url info and cache if needed
-    exceptions = []
-    if data is not str:
-        with ThreadPoolExecutor(max_workers=100) as executor:
-            print("Caching urls...")
-            future_cache = [executor.submit(cache_url, entry) for entry in data]
-
-            for future in tqdm(as_completed(future_cache), total=len(future_cache)):
-                future.result()
-
-    # Write any exceptions to a daily error log
-    # file_name = "ErrorLogs/" + datetime.now().strftime("%Y-%m-%d") + "_errorlog.txt"
-    # with open(file_name, "w") as error_log:
-    #     if len(exceptions) > 0:
-    #         json.dump(exceptions, fp=error_log, indent=4)
-    #     else:
-    #         error_log.write("no exceptions thrown")
+    response.raise_for_status()
+    return response.json()
 
 
 if __name__ == "__main__":
diff --git a/requirements.txt b/requirements.txt
index 15378a5..b483a61 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,3 +5,5 @@ idna==3.4
 requests==2.28.2
 savepagenow==1.2.3
 urllib3==1.26.15
+pytest==8.2.1
+tqdm==4.66.4
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