diff --git a/models/SiteModel.js b/models/SiteModel.js
index 1b15056..2a99592 100644
--- a/models/SiteModel.js
+++ b/models/SiteModel.js
@@ -3,6 +3,7 @@
  */
 
 const { supabase } = require('../auth');
+const { isValidDomain } = require('../helpers/utils');
 
 class SiteModel {
 
@@ -17,6 +18,21 @@ class SiteModel {
      * @returns {Promise<Object>} - The result of the insert operation.
      */
     async insert(name, domainName) {
+        // validate inputs
+        if (!name || !domainName) {
+            throw new Error('Name and domain name are required to insert a site.');
+        }
+
+        // validate domain name format
+        if (!isValidDomain(domainName)) {
+            throw new Error('Invalid domain name format.');
+        }
+
+        // check if the domain name already exists
+        if (await this.getByDomainName(domainName).then(data => data.length !== 0)) {
+            throw new Error('Domain name already exists.');
+        }
+
         const { data, error } = await supabase.from(SiteModel.tableName).insert({
             name: name,
             domain_name: domainName,
@@ -64,6 +80,24 @@ class SiteModel {
         return data;
     }
 
+    /**
+     * Retrieves a site by its domain name.
+     * 
+     * @param {string} domainName - The domain name of the site.
+     * 
+     * @returns {Promise<Object>} - The site object.
+     */
+    async getByDomainName(domainName) {
+        const { data, error } = await supabase.from(SiteModel.tableName).select('*').eq('domain_name', domainName);
+
+        if (error) {
+            console.error('Error fetching site by domain name:', error);
+            throw error;
+        }
+
+        return data;
+    }
+
 }
 
 module.exports = SiteModel;
\ No newline at end of file