diff --git a/helpers/utils.js b/helpers/utils.js
new file mode 100644
index 0000000..e9e7c46
--- /dev/null
+++ b/helpers/utils.js
@@ -0,0 +1,13 @@
+/**
+ * Utility functions for the application.
+ */
+
+const isValidDomain = (domain) => {
+  // Regular expression to validate a domain name
+  const domainRegex = /^(?!:\/\/)([a-zA-Z0-9-]+\.)+[a-zA-Z]{2,}$/;
+  return domainRegex.test(domain);
+}
+
+module.exports = {
+  isValidDomain
+};
diff --git a/models/SiteModel.js b/models/SiteModel.js
index b5894b4..4875b4b 100644
--- a/models/SiteModel.js
+++ b/models/SiteModel.js
@@ -3,6 +3,7 @@
  */
 
 const { supabase } = require('../auth');
+const { isValidDomain } = require('../helpers/utils');
 
 class SiteModel {
 
@@ -16,11 +17,25 @@ class SiteModel {
      * 
      * @returns {Promise<Object>} - The result of the insert operation.
      */
-    async insert(name, domainName) {
-        const { error } = await supabase.from(siteModel.tableName).insert({
-            name: name,
+    async insert(domainName) {
+        // validate inputs
+        if (!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({
             domain_name: domainName,
-        });
+        }).select();
 
         if (error) {
             console.error('Error inserting site:', error);
@@ -64,6 +79,24 @@ 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
diff --git a/routes/sites.js b/routes/sites.js
index 25db6db..7817f3c 100644
--- a/routes/sites.js
+++ b/routes/sites.js
@@ -21,8 +21,14 @@ router.get('/', async function(req, res, next) {
  */
 router.get('/:id', async function(req, res, next) {
     const siteId = req.params.id;
+    let site = null;
 
-    const site = await siteModel.getById(siteId);
+    try {
+        site = await siteModel.getById(siteId);
+    } catch (error) {
+        console.error('Error fetching site by ID:', error);
+        return res.status(400).send('Error fetching site: ' + error.message);
+    }
 
     if (!site) {
         return res.status(404).send('Site not found');
@@ -31,22 +37,52 @@ router.get('/:id', async function(req, res, next) {
     }
 });
 
+/**
+ * GET site by domain name.
+ * 
+ * Returns a specific site by its domain name in JSON format.
+ */
+router.get('/domain/:domain', async function(req, res, next) {
+    const domainName = req.params.domain;
+    let sites = null;
+
+    try {
+        sites = await siteModel.getByDomainName(domainName);
+    } catch (error) {
+        console.error('Error fetching site by domain name:', error);
+        return res.status(400).send('Error fetching site: ' + error.message);
+    }
+
+    console.log('Site found:', sites);
+
+    if (!sites || sites.length === 0) {
+        return res.status(404).send('Site not found');
+    } else {
+        res.json(sites[0]); // Return the first match
+    }
+});
+
 /**
  * POST create a new site.
  * 
  * Creates a new site with the provided domain name.
  * 
- * // TODO: Implement validation for domain name format
- * // TODO: Implement error handling for duplicate domains
  * // TODO: Ability to add additional site properties (e.g., name, description)
  */
-router.post('/add/:domain', function(req, res, next) {
-    const domain = req.params.domain;
-    
-    const newSite = siteModel.insert(domain);
+router.post('/add', async function(req, res, next) {
+    const domain = req.body.domain;
+    let newSite = null;
+
+    // insert method passes a lot of validation errors to the caller
+    try {
+        newSite = await siteModel.insert(domain);
+    } catch (error) {
+        console.error('Error creating site:', error);
+        return res.status(400).send('Error creating site: ' + error.message);
+    }
 
     if (!newSite) {
-        return res.status(400).send('Error creating site');
+        res.status(400).send('Error creating site');
     } else {
         res.status(201).json(newSite);
     }