diff --git a/src/controllers/openid_controller.rs b/src/controllers/openid_controller.rs
index 4c0d4af..edaa063 100644
--- a/src/controllers/openid_controller.rs
+++ b/src/controllers/openid_controller.rs
@@ -16,7 +16,7 @@ use crate::constants::*;
 use crate::controllers::base_controller::{build_fatal_error_page, redirect_user};
 use crate::data::action_logger::{Action, ActionLogger};
 use crate::data::app_config::AppConfig;
-use crate::data::client::{ClientID, ClientManager};
+use crate::data::client::{AuthenticationFlow, ClientID, ClientManager};
 use crate::data::code_challenge::CodeChallenge;
 use crate::data::current_user::CurrentUser;
 use crate::data::id_token::IdToken;
@@ -162,14 +162,6 @@ pub async fn authorize(
         return error_redirect(&query, "invalid_request", "openid scope missing!");
     }
 
-    if !query.response_type.eq("code") {
-        return error_redirect(
-            &query,
-            "invalid_request",
-            "Only code response type is supported!",
-        );
-    }
-
     if query.state.as_ref().map(String::is_empty).unwrap_or(false) {
         return error_redirect(&query, "invalid_request", "State is specified but empty!");
     }
@@ -201,45 +193,69 @@ pub async fn authorize(
         );
     }
 
-    // Save all authentication information in memory
-    let session = Session {
-        session_id: SessionID(rand_str(OPEN_ID_SESSION_LEN)),
-        client: client.id.clone(),
-        user: user.uid.clone(),
-        auth_time: SessionIdentity(Some(&id)).auth_time(),
-        redirect_uri,
-        authorization_code: rand_str(OPEN_ID_AUTHORIZATION_CODE_LEN),
-        authorization_code_expire_at: time() + OPEN_ID_AUTHORIZATION_CODE_TIMEOUT,
-        access_token: None,
-        access_token_expire_at: time() + OPEN_ID_ACCESS_TOKEN_TIMEOUT,
-        refresh_token: "".to_string(),
-        refresh_token_expire_at: 0,
-        nonce: query.0.nonce,
-        code_challenge,
-    };
-    sessions
-        .send(openid_sessions_actor::PushNewSession(session.clone()))
-        .await
-        .unwrap();
+    // Check that requested authorization flow is supported
+    if query.response_type != "code" && query.response_type != "id_token" {
+        return error_redirect(&query, "invalid_request", "Unsupported authorization flow!");
+    }
 
-    log::trace!("New OpenID session: {:#?}", session);
-    logger.log(Action::NewOpenIDSession { client: &client });
+    match (client.auth_flow(), query.response_type.as_str()) {
+        (AuthenticationFlow::AuthorizationCode, "code") => {
+            // Save all authentication information in memory
+            let session = Session {
+                session_id: SessionID(rand_str(OPEN_ID_SESSION_LEN)),
+                client: client.id.clone(),
+                user: user.uid.clone(),
+                auth_time: SessionIdentity(Some(&id)).auth_time(),
+                redirect_uri,
+                authorization_code: rand_str(OPEN_ID_AUTHORIZATION_CODE_LEN),
+                authorization_code_expire_at: time() + OPEN_ID_AUTHORIZATION_CODE_TIMEOUT,
+                access_token: None,
+                access_token_expire_at: time() + OPEN_ID_ACCESS_TOKEN_TIMEOUT,
+                refresh_token: "".to_string(),
+                refresh_token_expire_at: 0,
+                nonce: query.0.nonce,
+                code_challenge,
+            };
+            sessions
+                .send(openid_sessions_actor::PushNewSession(session.clone()))
+                .await
+                .unwrap();
 
-    HttpResponse::Found()
-        .append_header((
-            "Location",
-            format!(
-                "{}?{}session_state={}&code={}",
-                session.redirect_uri,
-                match &query.0.state {
-                    Some(state) => format!("state={}&", urlencoding::encode(state)),
-                    None => "".to_string(),
-                },
-                urlencoding::encode(&session.session_id.0),
-                urlencoding::encode(&session.authorization_code)
-            ),
-        ))
-        .finish()
+            log::trace!("New OpenID session: {:#?}", session);
+            logger.log(Action::NewOpenIDSession { client: &client });
+
+            HttpResponse::Found()
+                .append_header((
+                    "Location",
+                    format!(
+                        "{}?{}session_state={}&code={}",
+                        session.redirect_uri,
+                        match &query.0.state {
+                            Some(state) => format!("state={}&", urlencoding::encode(state)),
+                            None => "".to_string(),
+                        },
+                        urlencoding::encode(&session.session_id.0),
+                        urlencoding::encode(&session.authorization_code)
+                    ),
+                ))
+                .finish()
+        }
+
+        //(AuthenticationFlow::Implicit, "id_token") => {}
+        (flow, code) => {
+            log::warn!(
+                "For client {:?}, configured with flow {:?}, made request with code {}",
+                client.id,
+                flow,
+                code
+            );
+            error_redirect(
+                &query,
+                "invalid_request",
+                "Requested authentication flow is unsupported / not configured for this client!",
+            )
+        }
+    }
 }
 
 #[derive(serde::Serialize)]
diff --git a/src/data/client.rs b/src/data/client.rs
index daf72bd..fdc2538 100644
--- a/src/data/client.rs
+++ b/src/data/client.rs
@@ -4,6 +4,7 @@ use crate::utils::string_utils::apply_env_vars;
 #[derive(Clone, Debug, serde::Serialize, serde::Deserialize, Eq, PartialEq)]
 pub struct ClientID(pub String);
 
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum AuthenticationFlow {
     AuthorizationCode,
     Implicit,