diff --git a/src/Endpoint.php b/src/Endpoint.php
new file mode 100644
index 0000000..0686690
--- /dev/null
+++ b/src/Endpoint.php
@@ -0,0 +1,9 @@
+<?php declare(strict_types=1);
+
+namespace Lewisdale\Webmentions;
+
+use Lewisdale\Webmentions\Gateways\WebmentionGatewayInterface;
+
+class Endpoint {
+    private readonly WebmentionGatewayInterface $gateway;
+}
\ No newline at end of file
diff --git a/src/Gateways/SqliteGateway.php b/src/Gateways/SqliteGateway.php
new file mode 100644
index 0000000..96a8838
--- /dev/null
+++ b/src/Gateways/SqliteGateway.php
@@ -0,0 +1,85 @@
+<?php declare(strict_types=1);
+
+namespace Lewisdale\Webmentions\Gateways;
+
+use Exception;
+use Lewisdale\Webmentions\Models\Webmention;
+use PDO;
+
+class SqliteGateway extends WebmentionGatewayInterface {
+    private readonly PDO $connection;
+
+    function __construct(string $name)
+    {
+        $this->connection = new PDO("sqlite:$name");
+        $this->up();
+    }
+
+    protected function up() : void
+    {
+        // Create Webmention table
+        $sql = <<<SQL
+        CREATE TABLE IF NOT EXISTS webmentions (
+            id INTEGER PRIMARY KEY,
+            target TEXT NOT NULL,
+            source TEXT NOT NULL,
+            content TEXT,
+            author TEXT
+        );
+        SQL;
+
+        $this->connection->exec($sql);
+    }
+
+    public function get(int $id): ?Webmention
+    {
+        $sql = "SELECT * FROM webmentions;";
+        $statement = $this->connection->query($sql);
+
+        if ($statement == false) {
+            return null;
+        }
+
+        $row = $statement->fetch(PDO::FETCH_ASSOC);
+
+        if ($row) {
+            return new Webmention(
+                $row["id"],
+                $row["target"],
+                $row["source"],
+                $row["content"],
+                $row["author"]
+            );
+        }
+
+        return null;
+    }
+
+    public function getByPost(string $post): array
+    {
+        return [];
+    }
+
+    public function save(Webmention $webmention): ?int
+    {
+        $sql = <<< SQL
+        INSERT INTO webmentions
+            (id, target, source, content, author)
+        VALUES
+            (:id, :target, :source, :content, :author);
+        SQL;
+
+        $statement = $this->connection->prepare($sql);
+        $success = $statement->execute((array) $webmention);
+        $statement->closeCursor();
+    
+        return $success ? (int) $this->connection->lastInsertId() : null;
+    }
+
+    public function delete(Webmention $webmention): void
+    {
+        throw new Exception("Method " . SqliteGateway::class . "::delete not implemented");
+
+    }
+}
+?>
\ No newline at end of file
diff --git a/src/Gateways/WebmentionGatewayInterface.php b/src/Gateways/WebmentionGatewayInterface.php
new file mode 100644
index 0000000..9d996a5
--- /dev/null
+++ b/src/Gateways/WebmentionGatewayInterface.php
@@ -0,0 +1,15 @@
+<?php declare(strict_types=1);
+
+namespace Lewisdale\Webmentions\Gateways;
+
+use Lewisdale\Webmentions\Models\Webmention;
+
+abstract class WebmentionGatewayInterface {
+    abstract protected function up() : void;
+    abstract public function getByPost(string $post) : array;
+    abstract public function save(Webmention $webmention) : ?int;
+    abstract public function delete(Webmention $webmention) : void;
+    abstract public function get(int $id) : ?Webmention;
+}
+
+?>
\ No newline at end of file
diff --git a/src/Models/Webmention.php b/src/Models/Webmention.php
new file mode 100644
index 0000000..7e49dc0
--- /dev/null
+++ b/src/Models/Webmention.php
@@ -0,0 +1,19 @@
+<?php declare(strict_types=1);
+
+namespace Lewisdale\Webmentions\Models;
+
+class Webmention {
+    function __construct(
+        public ?int $id,
+        public string $target, // The target post
+        public string $source,
+        public ?string $content,
+        public ?string $author, // TODO: Should be reference to another model
+    )
+    {}
+
+    public function __toString() {
+        return "Webmention (id: {$this->id}, target: {$this->target}, source: {$this->source}, content: {$this->content}, author: {$this->author})";
+    }
+}
+?>
diff --git a/src/Webmention.php b/src/Webmention.php
index 078550a..9372fc3 100644
--- a/src/Webmention.php
+++ b/src/Webmention.php
@@ -2,6 +2,7 @@
 
 namespace Lewisdale\Webmentions;
 
+use Lewisdale\Webmentions\Gateways\WebmentionGatewayInterface;
 use Symfony\Component\DomCrawler\Crawler;
 use Symfony\Component\HttpClient\HttpClient;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
diff --git a/tests/Gateways/SqliteGatewayTest.php b/tests/Gateways/SqliteGatewayTest.php
new file mode 100644
index 0000000..181685f
--- /dev/null
+++ b/tests/Gateways/SqliteGatewayTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+error_reporting(E_ALL); ini_set('display_errors',1);
+
+
+use Lewisdale\Webmentions\Gateways\SqliteGateway;
+use Lewisdale\Webmentions\Models\Webmention;
+use PHPUnit\Framework\TestCase;
+
+class SqliteGatewayTest extends TestCase
+{
+    public function testCanInsertAWebmention()
+    {
+        $gateway = new SqliteGateway(":memory:");
+
+        $webmention = new Webmention(
+            null,
+            "https://lewisdale.dev/post/a-post",
+            "https://a-source.url",
+            "No content",
+            "Some Author Name"
+        );
+
+        $webmention->id = $gateway->save($webmention);
+        $this->assertNotNull($webmention->id);
+    }
+
+    public function testCanRetrieveAWebmention()
+    {
+        $gateway = new SqliteGateway(":memory:");
+
+        $webmention = new Webmention(
+            null,
+            "https://lewisdale.dev/post/a-post",
+            "https://a-source.url",
+            "No content",
+            "Some Author Name"
+        );
+
+        $webmention->id = $gateway->save($webmention);
+
+        $retrieved = $gateway->get($webmention->id);
+
+        $this->assertEquals($webmention, $retrieved, ((string) $webmention). " " . ((string) $retrieved));
+    }
+}