diff --git a/src/Examples/publish-event.php b/src/Examples/publish-event.php
index 3194e1f..b465613 100644
--- a/src/Examples/publish-event.php
+++ b/src/Examples/publish-event.php
@@ -8,6 +8,7 @@
 use swentel\nostr\Key\Key;
 use swentel\nostr\Message\EventMessage;
 use swentel\nostr\Relay\Relay;
+use swentel\nostr\Request\Request;
 use swentel\nostr\Sign\Sign;
 
 try {
@@ -28,13 +29,18 @@
     $relay = new Relay('wss://relay.nostr.band');
     $eventMessage = new EventMessage($note);
     $relay->setMessage($eventMessage);
-    /** @var \swentel\nostr\RelayResponse\RelayResponse $response */
-    $response = $relay->send();
+    $request = new Request($relay, $eventMessage);
+    $response = $request->send();
     // Handle response.
-    if ($response->isSuccess) {
-        print 'The event has been transmitted to the relay' . PHP_EOL;
-        $eventId = $response->eventId;
-        // Now we could request the event with this id.
+    foreach ($response as $relayUrl => $relayResponses) {
+        foreach ($relayResponses as $relayResponse) {
+            if ($relayResponse->isSuccess) {
+                print 'The event has been transmitted to the relay ' . $relayUrl . PHP_EOL;
+                $eventId = $relayResponse->eventId;
+                print 'The received event id from the relay: ' . $relayResponse->eventId;
+                // Now we could request the event with this id.
+            }
+        }
     }
 } catch (Exception $e) {
     print 'Exception error: ' . $e->getMessage() . PHP_EOL;
diff --git a/src/Examples/request-events-filtered-with-tags.php b/src/Examples/request-events-filtered-with-tags.php
new file mode 100644
index 0000000..fbc5242
--- /dev/null
+++ b/src/Examples/request-events-filtered-with-tags.php
@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+use swentel\nostr\Filter\Filter;
+use swentel\nostr\Message\RequestMessage;
+use swentel\nostr\Relay\Relay;
+use swentel\nostr\RelayResponse\RelayResponse;
+use swentel\nostr\RelayResponse\RelayResponseEvent;
+use swentel\nostr\Request\Request;
+use swentel\nostr\Subscription\Subscription;
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+try {
+    $subscription = new Subscription();
+    $subscriptionId = $subscription->setId();
+
+    $filter1 = new Filter();
+    $filter1->setKinds([1]);
+    $filter1->setLimit(25);
+    /**
+     * Please have a look at this overview with tags you can use according to the Nostr NIPs:
+     * https://nips.nostr.com/#standardized-tags
+     */
+    // Apply multiple tags to the filter.
+    $filter1->setTags(
+        [
+            '#t' => ['PHP', 'Drupal'],
+            '#p' => ['06639a386c9c1014217622ccbcf40908c4f1a0c33e23f8d6d68f4abf655f8f71'],
+        ],
+    );
+    // Apply a single tag to the filter which in this case will be appended to the #t tag.
+    $filter1->setTag('#t', ['Wordpress']);
+    // Apply an e-tag.
+    //$filter1->setLowercaseETags([
+    //    '06639a386c9c1014217622ccbcf40908c4f1a0c33e23f8d6d68f4abf655f8f71'
+    //]);
+    // Apply a p-tag.
+    //$filter1->setLowercasePTags([
+    //    '06639a386c9c1014217622ccbcf40908c4f1a0c33e23f8d6d68f4abf655f8f71'
+    //]);
+    /**
+     * If you're using multiple conditions in one filter, these conditions are interpreted as && (AND) conditions.
+     * If you would like to use || (OR) conditions, you should use multiple filters.
+     */
+    $filters = [$filter1];
+    $requestMessage = new RequestMessage($subscriptionId, $filters);
+    $relay = new Relay('wss://relay.nostr.band');
+    $request = new Request($relay, $requestMessage);
+    $response = $request->send();
+
+    /**
+     * @var string $relayUrl
+     *   The relay URL.
+     * @var object $relayResponse
+     *   RelayResponse which will contain the messages returned by the relay.
+     *   Each message will also contain the event.
+     */
+    foreach ($response as $relayUrl => $relayResponses) {
+        print 'Received ' . count($response[$relayUrl]) . ' message(s) received from relay ' . $relayUrl . PHP_EOL;
+        /** @var RelayResponse $relayResponse */
+        foreach ($relayResponses as $relayResponse) {
+            if ($relayResponse instanceof RelayResponseEvent) {
+                if (isset($relayResponse->event->content)) {
+                    print $relayResponse->event->content . PHP_EOL;
+                }
+            }
+        }
+    }
+} catch (Exception $e) {
+    print 'Exception error: ' . $e->getMessage() . PHP_EOL;
+}
diff --git a/src/Examples/request-events-from-multiple-relays.php b/src/Examples/request-events-from-multiple-relays.php
index 4e653ef..64571ee 100644
--- a/src/Examples/request-events-from-multiple-relays.php
+++ b/src/Examples/request-events-from-multiple-relays.php
@@ -48,5 +48,5 @@
         }
     }
 } catch (Exception $e) {
-    echo $e->getMessage();
+    print $e->getMessage() . PHP_EOL;
 }
diff --git a/src/Examples/request-events-with-auth.php b/src/Examples/request-events-with-auth.php
index 8da60ac..437e165 100644
--- a/src/Examples/request-events-with-auth.php
+++ b/src/Examples/request-events-with-auth.php
@@ -28,12 +28,12 @@
     $request = new Request($relay, $requestMessage);
     $response = $request->send();
 
-    foreach ($response as $relay => $messages) {
+    foreach ($response as $relay => $relayResponses) {
         print 'Received ' . count($response[$relay]) . ' message(s) received from relay ' . $relay . PHP_EOL;
-        foreach ($messages as $message) {
-            print $message->type . ': ' . $message->message . PHP_EOL;
-            if ($message instanceof RelayResponseEvent) {
-                $rawEvent = $message->event;
+        foreach ($relayResponses as $relayResponse) {
+            print 'Relay response ' . $relayResponse->type . ': ' . $relayResponse->message . PHP_EOL;
+            if ($relayResponse instanceof RelayResponseEvent) {
+                $rawEvent = $relayResponse->event;
                 $event = new Event();
                 $event->setId($rawEvent->id);
                 $event->setPublicKey($rawEvent->pubkey);
diff --git a/src/Examples/request-events.php b/src/Examples/request-events.php
index b560a5b..db8f109 100644
--- a/src/Examples/request-events.php
+++ b/src/Examples/request-events.php
@@ -26,19 +26,19 @@
     /**
      * @var string $relayUrl
      *   The relay URL.
-     * @var object $relayResponses
-     *   RelayResponses which will contain the messages returned by the relay.
+     * @var object $relayResponse
+     *   RelayResponse which will contain the messages returned by the relay.
      *   Each message will also contain the event.
      */
     foreach ($response as $relayUrl => $relayResponses) {
         print 'Received ' . count($response[$relayUrl]) . ' message(s) received from relay ' . $relayUrl . PHP_EOL;
         /** @var \swentel\nostr\RelayResponse\RelayResponseEvent $message */
-        foreach ($relayResponses as $message) {
-            if (isset($message->event->content)) {
-                print $message->event->content . PHP_EOL;
+        foreach ($relayResponses as $relayResponse) {
+            if (isset($relayResponse->event->content)) {
+                print $relayResponse->event->content . PHP_EOL;
             }
         }
     }
 } catch (Exception $e) {
-    print 'Exception error: ' . $e->getMessage() . '\n';
+    print 'Exception error: ' . $e->getMessage() . PHP_EOL;
 }
diff --git a/src/Filter/Filter.php b/src/Filter/Filter.php
index 1bc2543..a67f8eb 100644
--- a/src/Filter/Filter.php
+++ b/src/Filter/Filter.php
@@ -7,6 +7,8 @@
 use swentel\nostr\FilterInterface;
 use swentel\nostr\Key\Key;
 
+use function PHPUnit\Framework\throwException;
+
 class Filter implements FilterInterface
 {
     /**
@@ -24,6 +26,11 @@ class Filter implements FilterInterface
      */
     public array $kinds;
 
+    /**
+     * A list of tags values starting with a # followed by single letters (format: #<single-letter (a-zA-Z)>).
+     */
+    public array $tags;
+
     /**
      * A list of #e tag values (list of event ids)
      */
@@ -101,6 +108,68 @@ public function setKinds(array $kinds): static
         return $this;
     }
 
+    /**
+     * Set tags for the Filter object.
+     * Every tag in this filter property needs to start with a #.
+     *
+     * @param array $tags
+     *   The array of tags to set.
+     * @return Filter
+     */
+    public function setTags(array $tags): static
+    {
+        foreach ($tags as $name => $value) {
+            if (!is_array($value)) {
+                $message = sprintf('Provided tag value for %s must be an array', $name);
+                throw new \RuntimeException($message);
+            }
+            $this->validateTagName($name);
+            $this->setTag($name, $value);
+        }
+        return $this;
+    }
+
+    /**
+     * Set a single tag value for the Filter object.
+     *
+     * @param string $name
+     *   Tag name.
+     * @param string $value
+     *   Tag value.
+     * @return Filter
+     */
+    public function setTag(string $name, array $value): static
+    {
+        $this->validateTagName($name);
+        if (isset($this->{$name})) {
+            $this->{$name} = array_merge($this->{$name}, $value);
+        } else {
+            $this->{$name} = $value;
+        }
+        return $this;
+    }
+
+    /**
+     * Validate standardized tag.
+     *
+     * @param $tag
+     *   Provided tag name to be validated.
+     * @return void
+     */
+    private function validateTagName($tag): void
+    {
+        // Check if tag starts with #.
+        if (!str_starts_with($tag, '#')) {
+            throw new \RuntimeException('All tags must start with #');
+        }
+        // Check if tag has valid value.
+        $pattern = '/^#[a-z_-]+$/i';
+        if (!preg_match($pattern, $tag)) {
+            $message = sprintf('Invalid tag provided: %s', $tag);
+            throw new \RuntimeException($message);
+        }
+    }
+
     /**
      * Set the #e tag for the Filter object.
      *
@@ -146,6 +215,9 @@ public function setLowercasePTags(array $ptags): static
      */
     public function setSince(int $since): static
     {
+        if (!$this->isValidTimestamp($since)) {
+            throw new \RuntimeException("The provided since filter is not a valid timestamp");
+        }
         $this->since = $since;
         return $this;
     }
@@ -158,6 +230,9 @@ public function setSince(int $since): static
      */
     public function setUntil(int $until): static
     {
+        if (!$this->isValidTimestamp($until)) {
+            throw new \RuntimeException("The provided until filter is not a valid timestamp");
+        }
         $this->until = $until;
         return $this;
     }
diff --git a/src/Message/RequestMessage.php b/src/Message/RequestMessage.php
index a5d48fa..25b174f 100644
--- a/src/Message/RequestMessage.php
+++ b/src/Message/RequestMessage.php
@@ -37,9 +37,7 @@ public function __construct(string $subscriptionId, array $filters)
     {
         $this->subscriptionId = $subscriptionId;
         $this->setType(MessageTypeEnum::REQUEST);
-        foreach ($filters as $filter) {
-            $this->filters[] = $filter->toArray();
-        }
+        $this->processFilters($filters);
     }
 
     /**
@@ -63,4 +61,24 @@ public function generate(): string
         $requestArray = array_merge([$this->type, $this->subscriptionId], $this->filters);
         return json_encode($requestArray, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
     }
+
+    /**
+     * @param array $filters
+     *   Process filters for the request message.
+     * @return void
+     */
+    private function processFilters(array $filters): void
+    {
+        /** @var Filter\Filter $filter */
+        foreach ($filters as $filter) {
+            // Process tag values from $filter->tags.
+            if (isset($filter->tags)) {
+                foreach ($filter->tags as $key => $tag) {
+                    $filter->{$key} = [$tag];
+                }
+                unset($filter->tags);
+            }
+            $this->filters[] = $filter->toArray();
+        }
+    }
 }
diff --git a/src/Relay/Relay.php b/src/Relay/Relay.php
index d915e7d..e8ee74a 100644
--- a/src/Relay/Relay.php
+++ b/src/Relay/Relay.php
@@ -97,6 +97,7 @@ private function setPayload(string $payload): void
      */
     public function send(): RelayResponse
     {
+        // TODO: deprecate this and replace with $request->send($relay, $message) logic.
         $this->validateUrl();
 
         try {
diff --git a/src/Relay/RelaySet.php b/src/Relay/RelaySet.php
index 7fce751..43f1d19 100644
--- a/src/Relay/RelaySet.php
+++ b/src/Relay/RelaySet.php
@@ -114,6 +114,7 @@ public function isConnected(): bool
      */
     public function send(): array
     {
+        // TODO: deprecate this and replace with $request->send($relaySet, $message) logic.
         try {
             // Send message to each relay defined in this set.
             /** @var Relay $relay */
diff --git a/src/Request/Request.php b/src/Request/Request.php
index 737cbee..b7a3afd 100644
--- a/src/Request/Request.php
+++ b/src/Request/Request.php
@@ -6,6 +6,7 @@
 
 use swentel\nostr\Event\Event;
 use swentel\nostr\Message\AuthMessage;
+use swentel\nostr\MessageInterface;
 use swentel\nostr\Nip42\AuthEvent;
 use swentel\nostr\Relay\Relay;
 use swentel\nostr\Relay\RelaySet;
@@ -44,7 +45,7 @@ class Request implements RequestInterface
      * Constructor for the Request class.
      * Initializes the url and payload properties based on the provided websocket and message.
      */
-    public function __construct(Relay|RelaySet $relay, $message)
+    public function __construct(Relay|RelaySet $relay, MessageInterface $message)
     {
         if ($relay instanceof RelaySet) {
             $this->relays = $relay;
@@ -105,6 +106,7 @@ private function getResponseFromRelay(Relay $relay): array | RelayResponse
         $client->setTimeout(60);
         $client->text($this->payload);
 
+        // The Nostr subscription lifecycle within a websocket connection lifecycle.
         while ($response = $client->receive()) {
             if ($response === null) {
                 $response = [
@@ -119,19 +121,41 @@ private function getResponseFromRelay(Relay $relay): array | RelayResponse
             } elseif ($response instanceof Text) {
                 $relayResponse = RelayResponse::create(json_decode($response->getContent()));
                 $this->responses[] = $relayResponse;
+                // NIP-01 - Response OK from the relay.
+                if ($relayResponse->type === 'OK' && $relayResponse->status === false) {
+                    // Something went wrong, see message from the relay why.
+                    $client->disconnect();
+                    throw new \Exception($relayResponse->message);
+                }
+                if ($relayResponse->type === 'OK' && $relayResponse->status === true) {
+                    if (isset($relayResponse->eventId) && $relayResponse->eventId !== '') {
+                        // Event is transmitted to the relay.
+                        // TODO: send closeMessage to relay.
+                        $client->disconnect();
+                        break;
+                    }
+                }
+                // NIP-01 - Response EVENT from the relay.
+                if ($relayResponse->type === 'EVENT') {
+                    // Do nothing.
+                }
+                // NIP-01 - Response EOSE from the relay.
                 if ($relayResponse->type === 'EOSE') {
+                    // We should send closeMessage to the relay here.
                     $client->disconnect();
                     break;
                 }
                 if ($relayResponse->type === 'OK' && $relayResponse->status === false) {
+                    // We should send closeMessage to the relay here.
                     $client->disconnect();
                     throw new \Exception($relayResponse->message);
                 }
-                // NIP-42
+                // NIP-42 - Response AUTH from the relay.
                 if ($relayResponse->type === 'AUTH') {
                     // Save challenge string in session.
                     $_SESSION['challenge'] = $relayResponse->message;
                 }
+                // NIP-01 - Response CLOSED from the relay.
                 if ($relayResponse->type === 'CLOSED') {
                     // NIP-42
                     // We do need to broadcast a signed event verification here to the relay.
@@ -167,7 +191,9 @@ private function getResponseFromRelay(Relay $relay): array | RelayResponse
                             /** @var RelayResponse $response */
                             $response = RelayResponse::create(json_decode($message->getContent()));
                             $this->responses[] = $response;
+                            $client->stop();
                             if ($response->type === 'EOSE') {
+                                // We should send closeMessage to the relay here.
                                 $client->disconnect();
                             }
                         })->start();
@@ -179,10 +205,14 @@ private function getResponseFromRelay(Relay $relay): array | RelayResponse
                         $client->disconnect();
                         throw new \Exception($relayResponse->message);
                     }
+                    $client->disconnect();
+                    break;
                 }
             }
         }
-        $client->disconnect();
+        if ($client->isConnected()) {
+            $client->disconnect();
+        }
         $client->close();
         return $this->responses;
     }