diff --git a/backend/src/services/scheduler.rs b/backend/src/services/scheduler.rs
index 0983d3a..74e1b6c 100644
--- a/backend/src/services/scheduler.rs
+++ b/backend/src/services/scheduler.rs
@@ -90,3 +90,14 @@ pub async fn run_scheduled_jobs(state: &AppState) {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn current_day_code_returns_valid_code() {
+        let code = current_day_code();
+        assert!(["mon", "tue", "wed", "thu", "fri", "sat", "sun"].contains(&code));
+    }
+}
diff --git a/backend/tests/api_schedules_test.rs b/backend/tests/api_schedules_test.rs
index 44aa9a2..37f7bde 100644
--- a/backend/tests/api_schedules_test.rs
+++ b/backend/tests/api_schedules_test.rs
@@ -12,6 +12,7 @@
 mod common;
 
 use axum::http::StatusCode;
+use ai_synth_backend::db;
 
 fn require_test_db() -> bool {
     std::env::var("TEST_DATABASE_URL").is_ok()
@@ -400,3 +401,217 @@ async fn schedule_requires_theme_ownership() {
         "User B should get 404 when attempting to PUT schedule on User A's theme"
     );
 }
+
+// ═══════════════════════════════════════════════════════════════════════════
+// find_due_schedules — DB query logic
+// ═══════════════════════════════════════════════════════════════════════════
+
+/// Return (day_code, time_utc) for the current UTC moment.
+fn today_day_and_time() -> (String, String) {
+    use chrono::Datelike;
+    let now = chrono::Utc::now();
+    let day_code = match now.weekday() {
+        chrono::Weekday::Mon => "mon",
+        chrono::Weekday::Tue => "tue",
+        chrono::Weekday::Wed => "wed",
+        chrono::Weekday::Thu => "thu",
+        chrono::Weekday::Fri => "fri",
+        chrono::Weekday::Sat => "sat",
+        chrono::Weekday::Sun => "sun",
+    };
+    let time = now.format("%H:%M").to_string();
+    (day_code.to_string(), time)
+}
+
+/// Return the day code for the day *after* the current UTC day (wraps around).
+fn tomorrow_day_code() -> String {
+    use chrono::Datelike;
+    let tomorrow = chrono::Utc::now() + chrono::Duration::days(1);
+    match tomorrow.weekday() {
+        chrono::Weekday::Mon => "mon".to_string(),
+        chrono::Weekday::Tue => "tue".to_string(),
+        chrono::Weekday::Wed => "wed".to_string(),
+        chrono::Weekday::Thu => "thu".to_string(),
+        chrono::Weekday::Fri => "fri".to_string(),
+        chrono::Weekday::Sat => "sat".to_string(),
+        chrono::Weekday::Sun => "sun".to_string(),
+    }
+}
+
+#[tokio::test]
+async fn find_due_schedules_returns_matching_schedule() {
+    if !require_test_db() {
+        eprintln!("SKIPPED: TEST_DATABASE_URL not set");
+        return;
+    }
+
+    let app = common::TestApp::new().await;
+    let (_user_id, session) = app
+        .create_authenticated_user("find-due-match@example.com")
+        .await;
+
+    let theme_id = create_theme(&app, &session).await;
+
+    // Use today's day code and "00:00" so the schedule is always already due.
+    let (day_code, _) = today_day_and_time();
+    let body = serde_json::json!({
+        "enabled": true,
+        "days": [day_code],
+        "time_utc": "00:00",
+        "emails": []
+    });
+    let (status, _) = app
+        .put_with_session(
+            &format!("/api/v1/themes/{}/schedule", theme_id),
+            &body,
+            &session,
+        )
+        .await;
+    assert_eq!(status, StatusCode::OK);
+
+    let (day_code, current_time) = today_day_and_time();
+    let due = db::schedules::find_due_schedules(&app.pool, &day_code, &current_time)
+        .await
+        .expect("find_due_schedules should not fail");
+
+    let theme_uuid: uuid::Uuid = theme_id.parse().unwrap();
+    assert!(
+        due.iter().any(|s| s.theme_id == theme_uuid),
+        "Expected the schedule for theme {} to be returned as due, got: {:?}",
+        theme_id,
+        due.iter().map(|s| s.theme_id).collect::<Vec<_>>()
+    );
+}
+
+#[tokio::test]
+async fn find_due_schedules_skips_disabled_schedule() {
+    if !require_test_db() {
+        eprintln!("SKIPPED: TEST_DATABASE_URL not set");
+        return;
+    }
+
+    let app = common::TestApp::new().await;
+    let (_user_id, session) = app
+        .create_authenticated_user("find-due-disabled@example.com")
+        .await;
+
+    let theme_id = create_theme(&app, &session).await;
+
+    let (day_code, _) = today_day_and_time();
+    let body = serde_json::json!({
+        "enabled": false,
+        "days": [day_code],
+        "time_utc": "00:00",
+        "emails": []
+    });
+    let (status, _) = app
+        .put_with_session(
+            &format!("/api/v1/themes/{}/schedule", theme_id),
+            &body,
+            &session,
+        )
+        .await;
+    assert_eq!(status, StatusCode::OK);
+
+    let (day_code, current_time) = today_day_and_time();
+    let due = db::schedules::find_due_schedules(&app.pool, &day_code, &current_time)
+        .await
+        .expect("find_due_schedules should not fail");
+
+    let theme_uuid: uuid::Uuid = theme_id.parse().unwrap();
+    assert!(
+        !due.iter().any(|s| s.theme_id == theme_uuid),
+        "Disabled schedule should not appear in due list"
+    );
+}
+
+#[tokio::test]
+async fn find_due_schedules_skips_already_run_today() {
+    if !require_test_db() {
+        eprintln!("SKIPPED: TEST_DATABASE_URL not set");
+        return;
+    }
+
+    let app = common::TestApp::new().await;
+    let (_user_id, session) = app
+        .create_authenticated_user("find-due-already-run@example.com")
+        .await;
+
+    let theme_id = create_theme(&app, &session).await;
+
+    let (day_code, _) = today_day_and_time();
+    let body = serde_json::json!({
+        "enabled": true,
+        "days": [day_code],
+        "time_utc": "00:00",
+        "emails": []
+    });
+    let (status, resp) = app
+        .put_with_session(
+            &format!("/api/v1/themes/{}/schedule", theme_id),
+            &body,
+            &session,
+        )
+        .await;
+    assert_eq!(status, StatusCode::OK);
+
+    // Mark the schedule as already run
+    let schedule_id: uuid::Uuid = resp["id"].as_str().unwrap().parse().unwrap();
+    db::schedules::mark_run(&app.pool, schedule_id)
+        .await
+        .expect("mark_run should not fail");
+
+    let (day_code, current_time) = today_day_and_time();
+    let due = db::schedules::find_due_schedules(&app.pool, &day_code, &current_time)
+        .await
+        .expect("find_due_schedules should not fail");
+
+    let theme_uuid: uuid::Uuid = theme_id.parse().unwrap();
+    assert!(
+        !due.iter().any(|s| s.theme_id == theme_uuid),
+        "Already-run schedule should not appear in due list"
+    );
+}
+
+#[tokio::test]
+async fn find_due_schedules_skips_wrong_day() {
+    if !require_test_db() {
+        eprintln!("SKIPPED: TEST_DATABASE_URL not set");
+        return;
+    }
+
+    let app = common::TestApp::new().await;
+    let (_user_id, session) = app
+        .create_authenticated_user("find-due-wrong-day@example.com")
+        .await;
+
+    let theme_id = create_theme(&app, &session).await;
+
+    // Schedule for tomorrow only, so it must not be due today.
+    let wrong_day = tomorrow_day_code();
+    let body = serde_json::json!({
+        "enabled": true,
+        "days": [wrong_day],
+        "time_utc": "00:00",
+        "emails": []
+    });
+    let (status, _) = app
+        .put_with_session(
+            &format!("/api/v1/themes/{}/schedule", theme_id),
+            &body,
+            &session,
+        )
+        .await;
+    assert_eq!(status, StatusCode::OK);
+
+    let (day_code, current_time) = today_day_and_time();
+    let due = db::schedules::find_due_schedules(&app.pool, &day_code, &current_time)
+        .await
+        .expect("find_due_schedules should not fail");
+
+    let theme_uuid: uuid::Uuid = theme_id.parse().unwrap();
+    assert!(
+        !due.iter().any(|s| s.theme_id == theme_uuid),
+        "Schedule for a different day should not appear in due list"
+    );
+}