diff --git a/src/handlers.ts b/src/handlers.ts
index 1e7fc06..63a6d6e 100644
--- a/src/handlers.ts
+++ b/src/handlers.ts
@@ -53,6 +53,18 @@ app.post("/authorize", async (c) => {
     // redirect URL as query params = new URL("/callback", c.req.url).href to 
     // send the user back to callback endpoint.
     // The callback endpoint will get the encrypted token and decrypt it to get the user's access token.
+
+    // const targetURLAuthorize = new URL("callosum/v1/v2/auth/token/authorize", instanceUrl);
+    // targetURLAuthorize.searchParams.append('validity_time_in_sec', "86400");
+    // const targetURLCallbackPath = new URL("/callback", c.req.url);
+    // targetURLCallbackPath.searchParams.append('instanceUrl', instanceUrl);
+    // targetURLAuthorize.searchParams.append('redirect_url', btoa(targetURLCallbackPath.toString()));
+    // const encodedState = btoa(JSON.stringify(state.oauthReqInfo));
+    // targetURLAuthorize.searchParams.append('state', encodedState);
+    // targetURLAuthorize.searchParams.append('token_encryption_key', "1234567812345678");
+    // targetURLAuthorize.searchParams.append('encryption_algorithm', 'AES');
+    // redirectUrl.searchParams.append('targetURLPath', targetURLAuthorize.href);
+
     const targetURLPath = new URL("/callback", c.req.url);
     targetURLPath.searchParams.append('instanceUrl', instanceUrl);
     const encodedState = btoa(JSON.stringify(state.oauthReqInfo));
@@ -64,6 +76,13 @@ app.post("/authorize", async (c) => {
 })
 
 app.get("/callback", async (c) => {
+
+    // TODO(shikhar.bhargava): remove this once we have a proper callback URL
+    // With the proper callback URL, we will get the encrypted token in the query params
+    // along with it we will get the instanceUrl and the state (oauthReqInfo).
+    // and we will decrypt the token to get the user's access token and complete the authorization.
+    // const encodedOauthReqInfo = c.req.query('state');
+
     const instanceUrl = c.req.query('instanceUrl');
     const encodedOauthReqInfo = c.req.query('oauthReqInfo');
     if (!instanceUrl) {
diff --git a/src/oauth-manager/oauth-utils.ts b/src/oauth-manager/oauth-utils.ts
index b1200a5..b4af248 100644
--- a/src/oauth-manager/oauth-utils.ts
+++ b/src/oauth-manager/oauth-utils.ts
@@ -451,7 +451,7 @@ export function renderApprovalDialog(request: Request, options: ApprovalDialogOp
                   
                   <div class="form-group">
                     <label for="instanceUrl">ThoughtSpot Instance URL</label>
-                    <input type="url" id="instanceUrl" name="instanceUrl" required 
+                    <input type="text" id="instanceUrl" name="instanceUrl" required 
                            placeholder="https://your-instance.thoughtspot.cloud">
                   </div>
                   
@@ -498,6 +498,36 @@ export interface ParsedApprovalResult {
   }
   
 
+/**
+ * Validates and sanitizes a URL to ensure it's a valid ThoughtSpot instance URL
+ * @param url - The URL to validate and sanitize
+ * @returns The sanitized URL
+ * @throws Error if the URL is invalid
+ */
+function validateAndSanitizeUrl(url: string): string {
+    try {
+        // Remove any whitespace
+        const trimmedUrl = url.trim();
+        
+        // Add https:// if no protocol is specified
+        const urlWithProtocol = trimmedUrl.startsWith('http://') || trimmedUrl.startsWith('https://') 
+            ? trimmedUrl 
+            : `https://${trimmedUrl}`;
+        
+        const parsedUrl = new URL(urlWithProtocol);
+        
+        // Remove trailing slashes and normalize the URL
+        const sanitizedUrl = parsedUrl.origin;
+        
+        return sanitizedUrl;
+    } catch (e) {
+        if (e instanceof Error) {
+            throw new Error(`Invalid URL: ${e.message}`);
+        }
+        throw new Error('Invalid URL format');
+    }
+}
+
 /**
  * Parses the form submission from the approval dialog, extracts the state,
  * and generates Set-Cookie headers to mark the client as approved.
@@ -517,7 +547,7 @@ export async function parseRedirectApproval(request: Request): Promise<ParsedApp
     try {
         const formData = await request.formData()
         const encodedState = formData.get('state')
-        instanceUrl = formData.get('instanceUrl') as string;
+        const rawInstanceUrl = formData.get('instanceUrl') as string;
   
         if (typeof encodedState !== 'string' || !encodedState) {
             throw new Error("Missing or invalid 'state' in form data.")
@@ -530,9 +560,12 @@ export async function parseRedirectApproval(request: Request): Promise<ParsedApp
             throw new Error('Could not extract clientId from state object.')
         }
 
-        if (!instanceUrl) {
+        if (!rawInstanceUrl) {
             throw new Error('Missing instance URL')
         }
+
+        // Validate and sanitize the instance URL
+        instanceUrl = validateAndSanitizeUrl(rawInstanceUrl);
     } catch (e) {
         console.error('Error processing form submission:', e)
         throw new Error(`Failed to parse approval form: ${e instanceof Error ? e.message : String(e)}`)