diff --git a/README.md b/README.md
index b55741f..93b6466 100644
--- a/README.md
+++ b/README.md
@@ -372,3 +372,4 @@ Two important points:
 - [Measurement Protocol: Events](https://developers.google.com/analytics/devguides/collection/protocol/ga4/reference/events)
   - [Reserved Event Names](https://developers.google.com/analytics/devguides/collection/protocol/ga4/reference?client_type=gtag#reserved_event_names)
 - [Measurement Protocol: Validation](https://developers.google.com/analytics/devguides/collection/protocol/ga4/validating-events?client_type=gtag)
+- [Measurement Protocol: User Data](https://developers.google.com/analytics/devguides/collection/ga4/uid-data)
diff --git a/src/Analytics.php b/src/Analytics.php
index 9a0082b..20daca2 100644
--- a/src/Analytics.php
+++ b/src/Analytics.php
@@ -6,7 +6,6 @@
 use AlexWestergaard\PhpGa4\Helper;
 use AlexWestergaard\PhpGa4\Facade;
 use AlexWestergaard\PhpGa4\Exception\Ga4Exception;
-use AlexWestergaard\PhpGa4\Helper\ConsentHelper;
 
 /**
  * Analytics wrapper to contain UserProperties and Events to post on Google Analytics
@@ -15,7 +14,8 @@ class Analytics extends Helper\IOHelper implements Facade\Type\AnalyticsType
 {
     private Guzzle $guzzle;
 
-    private ConsentHelper $consent;
+    private Helper\ConsentHelper $consent;
+    private Helper\UserDataHelper $userdata;
 
     protected null|bool $non_personalized_ads = false;
     protected null|int $timestamp_micros;
@@ -31,7 +31,8 @@ public function __construct(
     ) {
         parent::__construct();
         $this->guzzle = new Guzzle();
-        $this->consent = new ConsentHelper();
+        $this->consent = new Helper\ConsentHelper();
+        $this->userdata = new Helper\UserDataHelper();
     }
 
     public function getParams(): array
@@ -106,11 +107,16 @@ public function addEvent(Facade\Type\EventType ...$events)
         return $this;
     }
 
-    public function consent(): ConsentHelper
+    public function consent(): Helper\ConsentHelper
     {
         return $this->consent;
     }
 
+    public function userdata(): Helper\UserDataHelper
+    {
+        return $this->userdata;
+    }
+
     public function post(): void
     {
         if (empty($this->measurement_id)) {
@@ -126,16 +132,21 @@ public function post(): void
 
         $body = array_replace_recursive(
             $this->toArray(),
+            ["user_data" => $this->user_id != null ? $this->userdata->toArray() : []], // Only accepted if user_id is passed too
             ["user_properties" => $this->user_properties],
             ["consent" => $this->consent->toArray()],
         );
 
+        if (count($body["user_data"]) < 1) unset($body["user_data"]);
+        if (count($body["user_properties"]) < 1) unset($body["user_properties"]);
+
         $chunkEvents = array_chunk($this->events, 25);
 
         if (count($chunkEvents) < 1) {
             throw Ga4Exception::throwMissingEvents();
         }
 
+        $this->userdata->reset();
         $this->user_properties = [];
         $this->events = [];
 
diff --git a/src/Helper/CountryIsoHelper.php b/src/Helper/CountryIsoHelper.php
new file mode 100644
index 0000000..f2e6d0d
--- /dev/null
+++ b/src/Helper/CountryIsoHelper.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace AlexWestergaard\PhpGa4\Helper;
+
+class CountryIsoHelper
+{
+    static public function valid(string $iso): bool
+    {
+        return array_search(mb_strtoupper(trim($iso)), [
+            "AF", "AX", "AL", "DZ", "AS", "AD", "AO", "AI", "AQ", "AG", "AR", "AM", "AW",
+            "AU", "AT", "AZ", "BS", "BH", "BD", "BB", "BY", "BE", "BZ", "BJ", "BM", "BT",
+            "BO", "BA", "BW", "BV", "BR", "IO", "BN", "BG", "BF", "BI", "KH", "CM", "CA",
+            "CV", "KY", "CF", "TD", "CL", "CN", "CX", "CC", "CO", "KM", "CG", "CD", "CK",
+            "CR", "CI", "HR", "CU", "CY", "CZ", "DK", "DJ", "DM", "DO", "EC", "EG", "SV",
+            "GQ", "ER", "EE", "ET", "FK", "FO", "FJ", "FI", "FR", "GF", "PF", "TF", "GA",
+            "GM", "GE", "DE", "GH", "GI", "GR", "GL", "GD", "GP", "GU", "GT", "GG", "GN",
+            "GW", "GY", "HT", "HM", "VA", "HN", "HK", "HU", "IS", "IN", "ID", "IR", "IQ",
+            "IE", "IM", "IL", "IT", "JM", "JP", "JE", "JO", "KZ", "KE", "KI", "KR", "KP",
+            "KW", "KG", "LA", "LV", "LB", "LS", "LR", "LY", "LI", "LT", "LU", "MO", "MK",
+            "MG", "MW", "MY", "MV", "ML", "MT", "MH", "MQ", "MR", "MU", "YT", "MX", "FM",
+            "MD", "MC", "MN", "ME", "MS", "MA", "MZ", "MM", "NA", "NR", "NP", "NL", "AN",
+            "NC", "NZ", "NI", "NE", "NG", "NU", "NF", "MP", "NO", "OM", "PK", "PW", "PS",
+            "PA", "PG", "PY", "PE", "PH", "PN", "PL", "PT", "PR", "QA", "RE", "RO", "RU",
+            "RW", "BL", "SH", "KN", "LC", "MF", "PM", "VC", "WS", "SM", "ST", "SA", "SN",
+            "RS", "SC", "SL", "SG", "SK", "SI", "SB", "SO", "ZA", "GS", "ES", "LK", "SD",
+            "SR", "SJ", "SZ", "SE", "CH", "SY", "TW", "TJ", "TZ", "TH", "TL", "TG", "TK",
+            "TO", "TT", "TN", "TR", "TM", "TC", "TV", "UG", "UA", "AE", "GB", "US", "UM",
+            "UY", "UZ", "VU", "VE", "VN", "VG", "VI", "WF", "EH", "YE", "ZM", "ZW",
+        ], true) !== false;
+    }
+}
diff --git a/src/Helper/UserDataHelper.php b/src/Helper/UserDataHelper.php
new file mode 100644
index 0000000..d3d656a
--- /dev/null
+++ b/src/Helper/UserDataHelper.php
@@ -0,0 +1,219 @@
+<?php
+
+namespace AlexWestergaard\PhpGa4\Helper;
+
+class UserDataHelper
+{
+    private ?string $sha256_email_address = null;
+    private ?string $sha256_phone_number = null;
+
+    private ?string $sha256_first_name = null;
+    private ?string $sha256_last_name = null;
+    private ?string $sha256_street = null;
+    private ?string $city = null;
+    private ?string $region = null;
+    private ?string $postal_code = null;
+    private ?string $country = null;
+
+    public function reset(): void
+    {
+        $this->sha256_email_address = null;
+        $this->sha256_phone_number = null;
+        $this->sha256_first_name = null;
+        $this->sha256_last_name = null;
+        $this->sha256_street = null;
+        $this->city = null;
+        $this->region = null;
+        $this->postal_code = null;
+        $this->country = null;
+    }
+
+    /**
+     * @param string $email
+     * @return bool
+     */
+    public function setEmail(string $email): bool
+    {
+        $email = str_replace(" ", "", mb_strtolower($email));
+        if (!filter_var($email, FILTER_VALIDATE_EMAIL)) return false;
+
+        // https://support.google.com/mail/answer/7436150
+        if (
+            substr($email, -mb_strlen("@gmail.com")) == "@gmail.com" ||
+            substr($email, -mb_strlen("@googlemail.com")) == "@googlemail.com"
+        ) {
+            [$addr, $host] = explode("@", $email, 2);
+            // https://support.google.com/mail/thread/125577450/gmail-and-googlemail
+            if ($host == "googlemail.com") {
+                $host = "gmail.com";
+            }
+            // https://gmail.googleblog.com/2008/03/2-hidden-ways-to-get-more-from-your.html
+            $addr = explode("+", $addr, 2)[0];
+            $addr = str_replace(".", "", $addr);
+            $email = implode("@", [trim($addr), trim($host)]);
+        }
+
+        $this->sha256_email_address = hash("sha256", $email);
+        return true;
+    }
+
+    /**
+     * @param int $number International number (without prefix "+" and dashes) eg. \
+     * "+1-123-4567890" for USA or\
+     * "+44-1234-5678900" for UK or\
+     * "+45-12345678" for DK
+     * @return bool
+     */
+    public function setPhone(int $number): bool
+    {
+        $sNumber = strval($number);
+        if (strlen($sNumber) < 3 || strlen($sNumber) > 15) {
+            return false;
+        }
+
+        $this->sha256_phone_number = hash("sha256", "+{$sNumber}");
+        return true;
+    }
+
+    /**
+     * @param string $firstName Users first name
+     * @return bool
+     */
+    public function setFirstName(string $firstName): bool
+    {
+        if (empty($firstName)) return false;
+        $this->sha256_first_name = hash("sha256", $this->strip($firstName, true));
+        return true;
+    }
+
+    /**
+     * @param string $lastName Users last name
+     * @return bool
+     */
+    public function setLastName(string $lastName): bool
+    {
+        if (empty($lastName)) return false;
+        $this->sha256_last_name = hash("sha256", $this->strip($lastName, true));
+        return true;
+    }
+
+    /**
+     * @param string $street Users street name
+     * @return bool
+     */
+    public function setStreet(string $street): bool
+    {
+        if (empty($street)) return false;
+        $this->sha256_street = hash("sha256", $this->strip($street));
+        return true;
+    }
+
+    /**
+     * @param string $city Users city name
+     * @return bool
+     */
+    public function setCity(string $city): bool
+    {
+        if (empty($city)) return false;
+        $this->city = $this->strip($city, true);
+        return true;
+    }
+
+    /**
+     * @param string $region Users region name
+     * @return bool
+     */
+    public function setRegion(string $region): bool
+    {
+        if (empty($region)) return false;
+        $this->region = $this->strip($region, true);
+        return true;
+    }
+
+    /**
+     * @param string $postalCode Users postal code
+     * @return bool
+     */
+    public function setPostalCode(string $postalCode): bool
+    {
+        if (empty($postalCode)) return false;
+        $this->postal_code = $this->strip($postalCode);
+        return true;
+    }
+
+    /**
+     * @param string $iso Users country (ISO)
+     * @return bool
+     */
+    public function setCountry(string $iso): bool
+    {
+        if (!CountryIsoHelper::valid($iso)) {
+            return false;
+        }
+
+        $this->country = mb_strtoupper(trim($iso));
+        return true;
+    }
+
+    public function toArray(): array
+    {
+        $res = [];
+
+        if (!empty($this->sha256_email_address)) {
+            $res["sha256_email_address"] = $this->sha256_email_address;
+        }
+
+        if (!empty($this->sha256_phone_number)) {
+            $res["sha256_phone_number"] = $this->sha256_phone_number;
+        }
+
+        $addr = [];
+
+        if (!empty($this->sha256_first_name)) {
+            $addr["sha256_first_name"] = $this->sha256_first_name;
+        }
+
+        if (!empty($this->sha256_last_name)) {
+            $addr["sha256_last_name"] = $this->sha256_last_name;
+        }
+
+        if (!empty($this->sha256_street)) {
+            $addr["sha256_street"] = $this->sha256_street;
+        }
+
+        if (!empty($this->city)) {
+            $addr["city"] = $this->city;
+        }
+
+        if (!empty($this->region)) {
+            $addr["region"] = $this->region;
+        }
+
+        if (!empty($this->postal_code)) {
+            $addr["postal_code"] = $this->postal_code;
+        }
+
+        if (!empty($this->country)) {
+            $addr["country"] = $this->country;
+        }
+
+        if (!empty($this->sha256_phone_number)) {
+            $res["sha256_phone_number"] = $this->sha256_phone_number;
+        }
+
+        if (count($addr) > 0) {
+            $res["address"] = $addr;
+        }
+
+        return $res;
+    }
+
+    private function strip(string $s, bool $removeDigits = false): string
+    {
+        $d = $removeDigits ? '0-9' : '';
+
+        $s = preg_replace("[^a-zA-Z{$d}\-\_\.\,\s]", "", $s);
+        $s = mb_strtolower($s);
+        return trim($s);
+    }
+}
diff --git a/test/Unit/UserDataTest.php b/test/Unit/UserDataTest.php
new file mode 100644
index 0000000..2055d81
--- /dev/null
+++ b/test/Unit/UserDataTest.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace AlexWestergaard\PhpGa4Test\Unit;
+
+use AlexWestergaard\PhpGa4\Event\Login;
+use AlexWestergaard\PhpGa4\Helper\UserDataHelper;
+use AlexWestergaard\PhpGa4Test\TestCase;
+
+final class UserDataTest extends TestCase
+{
+    public function test_user_data_is_fillable()
+    {
+        $uda = new UserDataHelper();
+        $this->assertTrue($uda->setEmail($setEmail = "test@gmail.com"));
+        $this->assertTrue($uda->setPhone($setPhone = 4500000000));
+        $this->assertTrue($uda->setFirstName($setFirstName = "test"));
+        $this->assertTrue($uda->setLastName($setLastName = "person"));
+        $this->assertTrue($uda->setStreet($setStreet = "some street 11"));
+        $this->assertTrue($uda->setCity($setCity = "somewhere"));
+        $this->assertTrue($uda->setRegion($setRegion = "inthere"));
+        $this->assertTrue($uda->setPostalCode($setPostalCode = "1234"));
+        $this->assertTrue($uda->setCountry($setCountry = "DK"));
+
+        $export = $uda->toArray();
+        $this->assertIsArray($export);
+        $this->assertEquals(hash("sha256", $setEmail), $export["sha256_email_address"], $setEmail);
+        $this->assertEquals(hash("sha256", '+' . $setPhone), $export["sha256_phone_number"], $setPhone);
+
+        $this->assertArrayHasKey("address", $export);
+        $this->assertIsArray($export["address"]);
+        $this->assertEquals(hash("sha256", $setFirstName), $export["address"]["sha256_first_name"], $setFirstName);
+        $this->assertEquals(hash("sha256", $setLastName), $export["address"]["sha256_last_name"], $setLastName);
+        $this->assertEquals(hash("sha256", $setStreet), $export["address"]["sha256_street"], $setStreet);
+        $this->assertEquals($setCity, $export["address"]["city"], $setCity);
+        $this->assertEquals($setRegion, $export["address"]["region"], $setRegion);
+        $this->assertEquals($setPostalCode, $export["address"]["postal_code"], $setPostalCode);
+        $this->assertEquals($setCountry, $export["address"]["country"], $setCountry);
+    }
+    public function test_user_data_is_sendable()
+    {
+        $uad = $this->analytics->userdata();
+        $uad->setEmail("test@gmail.com");
+        $uad->setPhone(4500000000);
+        $uad->setFirstName("test");
+        $uad->setLastName("person");
+        $uad->setStreet("some street 11");
+        $uad->setCity("somewhere");
+        $uad->setRegion("inthere");
+        $uad->setPostalCode("1234");
+        $uad->setCountry("DK");
+
+        $this->analytics->addEvent(Login::new());
+        $this->assertNull($this->analytics->post());
+    }
+}