diff --git a/src/bios.ts b/src/bios.ts
index c010ab2..7dd437a 100644
--- a/src/bios.ts
+++ b/src/bios.ts
@@ -1,50 +1,66 @@
 import { HTMLElement, parse } from "node-html-parser";
 
-class Bios {
+/**
+ * Represents a BIOS entry with version, date, changelog, and optional download URL.
+ */
+export class Bios {
+  /** BIOS release date (YYYY/MM/DD) */
   readonly date: string;
+  /** BIOS version string */
   readonly version: string;
+  /** BIOS changelog/description */
   readonly changelog: string;
-  readonly url: string | null;
+  /** Optional download URL for the BIOS file */
+  readonly url?: string;
 
+  /**
+   * @param date - BIOS release date
+   * @param version - BIOS version string
+   * @param changelog - BIOS changelog/description
+   * @param url - Optional download URL
+   * @throws Error if required fields are missing
+   */
   constructor(
     date: string,
     version: string,
     changelog: string,
-    url: string | null,
+    url?: string,
   ) {
-    if (!date || !version || !changelog) {
-      throw new Error("Required BIOS information missing");
+    if (!date?.trim() || !version?.trim() || !changelog?.trim()) {
+      throw new Error(
+        "Required BIOS information missing: date, version, or changelog",
+      );
     }
-
     this.date = date.trim();
     this.version = version.trim();
     this.changelog = changelog.trim();
-    this.url = url?.trim() || null;
+    this.url = url?.trim();
   }
 
+  /**
+   * Returns a formatted string representation of the BIOS entry.
+   */
   toString(): string {
-    return `${this.version} (${this.date}):\n${this.changelog}`;
+    return `${this.version} (${this.date}):\n  ${this.changelog}\n  ${this.url}`;
   }
 }
 
 /**
- * Fetches and parses BIOS information from a motherboard support page
+ * Fetches and parses BIOS information from a motherboard support page.
  * @param mobo - URL of the motherboard support page
  * @returns Promise containing array of Bios objects
  * @throws Error if the URL is invalid or parsing fails
  */
-async function getBios(mobo: string): Promise<Bios[]> {
-  if (!mobo || !mobo.startsWith("http")) {
-    throw new Error("Invalid motherboard URL");
+export async function getBios(mobo: string): Promise<Bios[]> {
+  if (!mobo || !/^https?:\/\//.test(mobo)) {
+    throw new Error("Invalid motherboard URL: must start with http or https");
   }
 
   try {
     const response = await fetch(mobo);
-
     if (!response.ok) {
       throw new Error(`HTTP ${response.status}: ${response.statusText}`);
     }
-
     const body = await response.text();
     const root = parse(body);
     const biosList: Bios[] = [];
@@ -57,15 +73,12 @@ async function getBios(mobo: string): Promise<Bios[]> {
 
     for (const tr of rows) {
       try {
-        const bios = parseBiosRow(tr);
-        if (bios) {
-          biosList.push(bios);
-        }
+        biosList.push(parseBiosRow(tr));
       } catch (error) {
-        console.error("Failed to parse BIOS row:", error);
+        const message = error instanceof Error ? error.message : String(error);
+        console.error("Failed to parse BIOS row:", message);
       }
     }
-
     return biosList;
   } catch (error) {
     const message = error instanceof Error ? error.message : String(error);
@@ -74,22 +87,29 @@ async function getBios(mobo: string): Promise<Bios[]> {
 }
 
 /**
- * Parses a table row into a Bios object
+ * Parses a table row into a Bios object.
  * @param tr - HTML table row element
- * @returns Bios object or null if parsing fails
+ * @returns Bios object
+ * @throws Error if the row format is invalid
  */
-function parseBiosRow(tr: HTMLElement): Bios | null {
+function parseBiosRow(tr: HTMLElement): Bios {
   try {
     const tds = tr.querySelectorAll("td");
     if (tds.length < 6) {
-      throw new Error("Invalid table row format");
+      throw new Error(
+        `Invalid table row format: expected >=6 columns, got ${tds.length}`,
+      );
     }
-
+    // Try to resolve the link to an absolute URL if possible
     const link = tds[5].querySelector("a")?.getAttribute("href");
-    const url = link
-      ? encodeURI(link).replace(/[(]/g, "%28").replace(/[)]/g, "%29")
-      : null;
-
+    let url: string | undefined = undefined;
+    if (link) {
+      try {
+        url = encodeURI(link).replace(/[(]/g, "%28").replace(/[)]/g, "%29");
+      } catch {
+        url = link;
+      }
+    }
     return new Bios(
       tds[1].text, // date
       tds[0].text, // version
@@ -97,9 +117,7 @@ function parseBiosRow(tr: HTMLElement): Bios | null {
       url,
     );
   } catch (error) {
-    console.error("Error parsing row:", error);
-    return null;
+    const message = error instanceof Error ? error.message : String(error);
+    throw new Error(`Error parsing BIOS row: ${message}`);
   }
 }
-
-export { Bios, getBios };
diff --git a/src/index.ts b/src/index.ts
index c58ab41..2f174df 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -34,18 +34,17 @@ async function main() {
       );
 
       if (!uploaded) {
-        throw new Error("Failed to upload updated BIOS list");
+        console.error("Failed to upload updated BIOS list");
       }
 
       // Send notification
       const message = formatNotificationMessage(newBios);
+      console.log("Sending notification:", message);
       const notified = await notify(message);
 
       if (!notified.success) {
-        throw new Error(`Failed to send notification: ${notified.error}`);
+        console.error(`Failed to send notification: ${notified.error}`);
       }
-
-      console.log("Successfully updated BIOS list and sent notification");
     } else {
       console.log("No new BIOS versions found");
     }
diff --git a/src/notify.ts b/src/notify.ts
index ba226c1..6f2a28d 100644
--- a/src/notify.ts
+++ b/src/notify.ts
@@ -6,17 +6,17 @@ const requiredEnvVars = ["SMS_WEBHOOK_URL", "SMS_USER", "SMS_PASS"] as const;
 // Validate environment variables on module load
 for (const envVar of requiredEnvVars) {
   if (!process.env[envVar]) {
-    throw new Error(`Missing required environment variable: ${envVar}`);
+    console.error(`Missing required environment variable: ${envVar}`);
   }
 }
 
-interface NotificationPayload {
+export interface NotificationPayload {
   msg: string;
   user: string;
   pass: string;
 }
 
-interface NotificationResult {
+export interface NotificationResult {
   success: boolean;
   error?: string;
 }
@@ -27,7 +27,7 @@ interface NotificationResult {
  * @returns Promise with the notification result
  * @throws Error if the message is empty or if environment variables are missing
  */
-async function notify(msg: string): Promise<NotificationResult> {
+export async function notify(msg: string): Promise<NotificationResult> {
   // Input validation
   if (!msg || msg.trim().length === 0) {
     return {
@@ -37,6 +37,14 @@ async function notify(msg: string): Promise<NotificationResult> {
   }
 
   const webhookUrl = process.env.SMS_WEBHOOK_URL!;
+
+  if (!webhookUrl) {
+    return {
+      success: false,
+      error: "Missing webhook url",
+    };
+  }
+
   const payload: NotificationPayload = {
     msg: msg.trim().substring(0, 160),
     user: process.env.SMS_USER!,
@@ -72,5 +80,3 @@ async function notify(msg: string): Promise<NotificationResult> {
     };
   }
 }
-
-export { type NotificationPayload, type NotificationResult, notify };
diff --git a/src/s3.ts b/src/s3.ts
index 3a5b6c9..21c1786 100644
--- a/src/s3.ts
+++ b/src/s3.ts
@@ -8,18 +8,23 @@ const requiredEnvVars = [
   "AWS_SECRET_ACCESS_KEY",
 ] as const;
 
-for (const envVar of requiredEnvVars) {
-  if (!process.env[envVar]) {
-    throw new Error(`Missing required environment variable: ${envVar}`);
+function initS3(): S3Client | undefined {
+  for (const envVar of requiredEnvVars) {
+    if (!process.env[envVar]) {
+      console.error(`Missing required environment variable: ${envVar}`);
+      return undefined;
+    }
+
+    return new S3Client({
+      region: process.env.AWS_DEFAULT_REGION!,
+      endPoint: process.env.AWS_ENDPOINT_URL!,
+      accessKey: process.env.AWS_ACCESS_KEY_ID!,
+      secretKey: process.env.AWS_SECRET_ACCESS_KEY!,
+    });
   }
 }
 
-const s3client = new S3Client({
-  region: process.env.AWS_DEFAULT_REGION!,
-  endPoint: process.env.AWS_ENDPOINT_URL!,
-  accessKey: process.env.AWS_ACCESS_KEY_ID!,
-  secretKey: process.env.AWS_SECRET_ACCESS_KEY!,
-});
+const s3client: S3Client | undefined = initS3();
 
 /**
  * get object from S3
@@ -28,14 +33,18 @@ const s3client = new S3Client({
  * @returns Promise containing the content
  * @throws Error if key or bucket is empty
  */
-async function getObject<Type>(
+export async function getObject<Type>(
   key: string,
   bucket: string,
-): Promise<Type | null> {
+): Promise<Type | undefined> {
   if (!key || !bucket) {
     throw new Error("Key and bucket must not be empty");
   }
 
+  if (!s3client) {
+    return undefined;
+  }
+
   try {
     const response = await s3client.getObject(key, { bucketName: bucket });
     if (!response.ok) {
@@ -44,7 +53,7 @@ async function getObject<Type>(
     return response.json();
   } catch (error) {
     console.error(`Unexpected error downloading ${key}:`, error);
-    return null;
+    return undefined;
   }
 }
 
@@ -57,7 +66,7 @@ async function getObject<Type>(
  * @returns Promise<boolean> indicating success or failure
  * @throws Error if key or bucket is empty
  */
-async function putObject<Type>(
+export async function putObject<Type>(
   content: Type,
   key: string,
   bucket: string,
@@ -67,6 +76,10 @@ async function putObject<Type>(
     throw new Error("Key and bucket must not be empty");
   }
 
+  if (!s3client) {
+    return false;
+  }
+
   try {
     const response = await s3client.putObject(
       key,
@@ -86,5 +99,3 @@ async function putObject<Type>(
     return false;
   }
 }
-
-export { getObject, putObject };