diff --git a/packages/Lvl0/FediDiscover/src/Actions/PollFediverseAction.php b/packages/Lvl0/FediDiscover/src/Actions/PollFediverseAction.php
new file mode 100644
index 0000000..3200b87
--- /dev/null
+++ b/packages/Lvl0/FediDiscover/src/Actions/PollFediverseAction.php
@@ -0,0 +1,55 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lvl0\FediDiscover\Actions;
+
+use Lvl0\FediDiscover\Clients\FediverseClient;
+use Lvl0\FediDiscover\Clients\FediversePost;
+use Lvl0\FediDiscover\Events\UrlDiscovered;
+use Lvl0\FediDiscover\Models\Instance;
+
+class PollFediverseAction
+{
+    public function __construct(private FediverseClient $client) {}
+
+    public function execute(Instance $instance): void
+    {
+        $posts = collect($this->client->fetchPostsSince($instance, $instance->last_seen_id));
+
+        $posts->each(function (FediversePost $post) use ($instance) {
+            $this->processLinks($post, $instance);
+        });
+
+        if ($posts->isNotEmpty()) {
+            $instance->last_seen_id = $posts->first()->cursorId;
+        }
+
+        $instance->last_polled_at = now();
+        $instance->save();
+    }
+
+    private function processLinks(FediversePost $post, Instance $instance): void
+    {
+        if ($post->body === null) {
+            return;
+        }
+
+        $linksFound = preg_match_all('~https?://[^\s<>"\'()\[\]]+~', $post->body, $matches);
+
+        if ($linksFound === 0) {
+            return;
+        }
+
+        $urls = collect($matches[0])
+            ->map(fn (string $u) => rtrim($u, '.,;:!?'))
+            ->filter(fn (string $u) => filter_var($u, FILTER_VALIDATE_URL) !== false)
+            ->filter(fn (string $u) => parse_url($u, PHP_URL_HOST) !== parse_url($instance->url, PHP_URL_HOST))
+            ->unique()
+            ->each(fn (string $url) => UrlDiscovered::dispatch(
+                url: $url,
+                postUrl: $post->selfUrl,
+                postBody: $post->body,
+            ));
+    }
+}
diff --git a/packages/Lvl0/FediDiscover/src/Clients/FediverseClient.php b/packages/Lvl0/FediDiscover/src/Clients/FediverseClient.php
new file mode 100644
index 0000000..c69049d
--- /dev/null
+++ b/packages/Lvl0/FediDiscover/src/Clients/FediverseClient.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lvl0\FediDiscover\Clients;
+
+use Lvl0\FediDiscover\Models\Instance;
+
+interface FediverseClient
+{
+    public function fetchPostsSince(Instance $instance, ?string $lastSeenId): array;
+}
diff --git a/packages/Lvl0/FediDiscover/src/Clients/FediversePost.php b/packages/Lvl0/FediDiscover/src/Clients/FediversePost.php
new file mode 100644
index 0000000..fa1c87e
--- /dev/null
+++ b/packages/Lvl0/FediDiscover/src/Clients/FediversePost.php
@@ -0,0 +1,14 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lvl0\FediDiscover\Clients;
+
+class FediversePost
+{
+    public function __construct(
+        public string $cursorId,
+        public string $selfUrl,
+        public ?string $body
+    ) {}
+}
diff --git a/packages/Lvl0/FediDiscover/src/Events/UrlDiscovered.php b/packages/Lvl0/FediDiscover/src/Events/UrlDiscovered.php
index b63eb1e..024cb35 100644
--- a/packages/Lvl0/FediDiscover/src/Events/UrlDiscovered.php
+++ b/packages/Lvl0/FediDiscover/src/Events/UrlDiscovered.php
@@ -13,8 +13,8 @@ class UrlDiscovered
 
     public function __construct(
         public string $url,
-        public ?string $postUrl,
-        public ?string $postBody
+        public ?string $postUrl = null,
+        public ?string $postBody = null
     ) {}
 
     public function broadcastOn(): array
diff --git a/packages/Lvl0/FediDiscover/src/Models/Instance.php b/packages/Lvl0/FediDiscover/src/Models/Instance.php
index da751f9..cabee28 100644
--- a/packages/Lvl0/FediDiscover/src/Models/Instance.php
+++ b/packages/Lvl0/FediDiscover/src/Models/Instance.php
@@ -19,7 +19,7 @@
  * @property bool $enabled
  * @property int $interval_seconds
  * @property array<string, mixed> $extras
- * @property int $last_seen_id
+ * @property string|null $last_seen_id
  * @property Carbon|null $last_polled_at
  * @property Carbon $created_at
  * @property Carbon $updated_at
diff --git a/packages/Lvl0/FediDiscover/tests/Feature/PollFediverseActionTest.php b/packages/Lvl0/FediDiscover/tests/Feature/PollFediverseActionTest.php
new file mode 100644
index 0000000..48abc09
--- /dev/null
+++ b/packages/Lvl0/FediDiscover/tests/Feature/PollFediverseActionTest.php
@@ -0,0 +1,223 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lvl0\FediDiscover\Tests\Feature;
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Event;
+use Lvl0\FediDiscover\Actions\PollFediverseAction;
+use Lvl0\FediDiscover\Clients\FediverseClient;
+use Lvl0\FediDiscover\Clients\FediversePost;
+use Lvl0\FediDiscover\Config\InstanceType;
+use Lvl0\FediDiscover\Events\UrlDiscovered;
+use Lvl0\FediDiscover\Models\Instance;
+use Mockery;
+use Tests\TestCase;
+
+class PollFediverseActionTest extends TestCase
+{
+    use RefreshDatabase;
+
+    public function test_it_fires_one_event_per_extracted_url(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'See https://example.com/one and https://other.example/two'),
+        ]);
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://example.com/one');
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://other.example/two');
+        Event::assertDispatchedTimes(UrlDiscovered::class, 2);
+    }
+
+    public function test_it_extracts_urls_from_html_anchor_tags(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', '<p>Check <a href="https://example.com/article">this</a>!</p>'),
+        ]);
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://example.com/article');
+        Event::assertDispatchedTimes(UrlDiscovered::class, 1);
+    }
+
+    public function test_it_extracts_urls_from_markdown_links(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll(
+            posts: [new FediversePost('1', 'https://lemmy.world/post/42', 'A [great article](https://example.com/article) about trees.')],
+            instanceUrl: 'https://lemmy.world',
+        );
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://example.com/article');
+        Event::assertDispatchedTimes(UrlDiscovered::class, 1);
+    }
+
+    public function test_it_strips_trailing_punctuation_from_urls(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'Check https://example.com/article, it is great. Also https://other.example/page.'),
+        ]);
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://example.com/article');
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://other.example/page');
+    }
+
+    public function test_it_deduplicates_urls_within_a_single_post(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'Here is https://example.com/article and again https://example.com/article'),
+        ]);
+
+        Event::assertDispatchedTimes(UrlDiscovered::class, 1);
+    }
+
+    public function test_it_filters_urls_on_the_polling_instance_host(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'See https://mastodon.social/@bob/42 and https://example.com/article'),
+        ]);
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->url === 'https://example.com/article');
+        Event::assertDispatchedTimes(UrlDiscovered::class, 1);
+    }
+
+    public function test_it_ignores_posts_with_a_null_body(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', null),
+        ]);
+
+        Event::assertNotDispatched(UrlDiscovered::class);
+    }
+
+    public function test_it_ignores_non_http_schemes(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'Email mailto:alice@example.com or try ftp://files.example.com/x'),
+        ]);
+
+        Event::assertNotDispatched(UrlDiscovered::class);
+    }
+
+    public function test_it_passes_post_self_url_and_body_through_to_the_event(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $body = 'Here is https://example.com/article with surrounding context.';
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', $body),
+        ]);
+
+        Event::assertDispatched(UrlDiscovered::class, fn (UrlDiscovered $e) => $e->postUrl === 'https://mastodon.social/@alice/1' && $e->postBody === $body
+        );
+    }
+
+    public function test_it_processes_multiple_posts(): void
+    {
+        Event::fake([UrlDiscovered::class]);
+
+        $this->poll([
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'See https://example.com/one'),
+            new FediversePost('2', 'https://mastodon.social/@bob/2', 'Also https://example.com/two'),
+        ]);
+
+        Event::assertDispatchedTimes(UrlDiscovered::class, 2);
+    }
+
+    public function test_it_updates_last_seen_id_to_the_first_posts_cursor(): void
+    {
+        $instance = $this->makeInstance();
+
+        // Clients return newest-first; the action treats posts[0]
+        // as the new high-water mark without inspecting cursor values.
+        $this->pollInstance($instance, [
+            new FediversePost('newest-cursor', 'https://mastodon.social/@alice/3', 'x'),
+            new FediversePost('middle-cursor', 'https://mastodon.social/@bob/2', 'y'),
+            new FediversePost('oldest-cursor', 'https://mastodon.social/@carol/1', 'z'),
+        ]);
+
+        $this->assertSame('newest-cursor', $instance->fresh()->last_seen_id);
+    }
+
+    public function test_it_updates_last_polled_at(): void
+    {
+        $instance = $this->makeInstance();
+        $this->assertNull($instance->last_polled_at);
+
+        $this->pollInstance($instance, [
+            new FediversePost('1', 'https://mastodon.social/@alice/1', 'x'),
+        ]);
+
+        $this->assertNotNull($instance->fresh()->last_polled_at);
+    }
+
+    public function test_it_passes_the_existing_last_seen_id_to_the_client(): void
+    {
+        $instance = $this->makeInstance(['last_seen_id' => '999']);
+
+        $client = Mockery::mock(FediverseClient::class);
+        $client->shouldReceive('fetchPostsSince')
+            ->once()
+            ->with($instance, $instance->last_seen_id)
+            ->andReturn([]);
+
+        (new PollFediverseAction($client))->execute($instance);
+    }
+
+    public function test_it_leaves_last_seen_id_unchanged_when_no_posts_are_returned(): void
+    {
+        $instance = $this->makeInstance(['last_seen_id' => '500']);
+
+        $this->pollInstance($instance, []);
+
+        $this->assertSame('500', $instance->fresh()->last_seen_id);
+    }
+
+    /**
+     * @param  array<FediversePost>  $posts
+     */
+    private function poll(array $posts, string $instanceUrl = 'https://mastodon.social'): void
+    {
+        $this->pollInstance($this->makeInstance(['url' => $instanceUrl]), $posts);
+    }
+
+    /**
+     * @param  array<FediversePost>  $posts
+     */
+    private function pollInstance(Instance $instance, array $posts): void
+    {
+        $client = Mockery::mock(FediverseClient::class);
+        $client->shouldReceive('fetchPostsSince')->andReturn($posts);
+
+        (new PollFediverseAction($client))->execute($instance);
+    }
+
+    /**
+     * @param  array<string, mixed>  $overrides
+     */
+    private function makeInstance(array $overrides = []): Instance
+    {
+        return Instance::create(array_merge([
+            'type' => InstanceType::Mastodon,
+            'url' => 'https://mastodon.social',
+            'enabled' => true,
+            'interval_seconds' => 600,
+        ], $overrides));
+    }
+}