diff --git a/src/ConnectionConfig.php b/src/ConnectionConfig.php
new file mode 100644
index 0000000..da3810c
--- /dev/null
+++ b/src/ConnectionConfig.php
@@ -0,0 +1,7 @@
+<?php
+
+namespace Amp\Sql;
+
+interface ConnectionConfig {
+    public function connectionString(): string;
+}
diff --git a/src/Connector.php b/src/Connector.php
new file mode 100644
index 0000000..5014dfe
--- /dev/null
+++ b/src/Connector.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Amp\Sql;
+
+use Amp\Promise;
+
+interface Connector {
+    /**
+     * @param ConnectionConfig $config
+     *
+     * @return Promise<Connection>
+     */
+    public function connect(ConnectionConfig $config): Promise;
+}