diff --git a/src/identity/application/port/output/db/errors.rs b/src/identity/application/port/output/db/errors.rs
new file mode 100644
index 0000000..09a9874
--- /dev/null
+++ b/src/identity/application/port/output/db/errors.rs
@@ -0,0 +1,14 @@
+// SPDX-FileCopyrightText: 2024 Aravinth Manivannan <realaravinth@batsense.net>
+//
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use derive_more::Display;
+use serde::{Deserialize, Serialize};
+
+pub type OutDBPortResult<V> = Result<V, OutDBPortError>;
+
+#[derive(Debug, Display, Clone, Serialize, Deserialize, PartialEq, Eq, PartialOrd, Ord)]
+pub enum OutDBPortError {
+    InternalError,
+    VerificationOTPSecretExists,
+}
diff --git a/src/identity/application/port/output/db/mod.rs b/src/identity/application/port/output/db/mod.rs
new file mode 100644
index 0000000..b3e3eeb
--- /dev/null
+++ b/src/identity/application/port/output/db/mod.rs
@@ -0,0 +1,10 @@
+// SPDX-FileCopyrightText: 2024 Aravinth Manivannan <realaravinth@batsense.net>
+//
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+pub mod create_verification_secret;
+pub mod email_exists;
+pub mod errors;
+pub mod username_exists;
+//pub mod get_verification_secret;
+//pub mod delete_verification_secret;
diff --git a/src/identity/application/port/output/db/username_exists.rs b/src/identity/application/port/output/db/username_exists.rs
new file mode 100644
index 0000000..2bcacbc
--- /dev/null
+++ b/src/identity/application/port/output/db/username_exists.rs
@@ -0,0 +1,42 @@
+// SPDX-FileCopyrightText: 2024 Aravinth Manivannan <realaravinth@batsense.net>
+//
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+use mockall::predicate::*;
+use mockall::*;
+
+use super::errors::*;
+#[cfg(test)]
+#[allow(unused_imports)]
+pub use tests::*;
+
+#[automock]
+#[async_trait::async_trait]
+pub trait UsernameExistsOutDBPort: Send + Sync {
+    async fn username_exists(&self, username: &str) -> OutDBPortResult<bool>;
+}
+
+pub type UsernameExistsOutDBPortObj = std::sync::Arc<dyn UsernameExistsOutDBPort>;
+
+#[cfg(test)]
+pub mod tests {
+    use super::*;
+
+    use std::sync::Arc;
+
+    pub fn mock_username_exists_db_port(
+        times: Option<usize>,
+        returning: bool,
+    ) -> UsernameExistsOutDBPortObj {
+        let mut m = MockUsernameExistsOutDBPort::new();
+        if let Some(times) = times {
+            m.expect_username_exists()
+                .times(times)
+                .returning(move |_| Ok(returning));
+        } else {
+            m.expect_username_exists().returning(move |_| Ok(returning));
+        }
+
+        Arc::new(m)
+    }
+}