diff --git a/crates/cli/src/commands/manage.rs b/crates/cli/src/commands/manage.rs
index c608db83..2f3e8852 100644
--- a/crates/cli/src/commands/manage.rs
+++ b/crates/cli/src/commands/manage.rs
@@ -21,7 +21,7 @@ use mas_storage::{
     oauth2::OAuth2ClientRepository,
     upstream_oauth2::UpstreamOAuthProviderRepository,
     user::{UserEmailRepository, UserPasswordRepository, UserRepository},
-    Clock, Repository,
+    Repository, SystemClock,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::scope::Scope;
@@ -188,7 +188,7 @@ impl Options {
     #[allow(clippy::too_many_lines)]
     pub async fn run(&self, root: &super::Options) -> anyhow::Result<()> {
         use Subcommand as SC;
-        let clock = Clock::default();
+        let clock = SystemClock::default();
         // XXX: we should disallow SeedableRng::from_entropy
         let mut rng = rand_chacha::ChaChaRng::from_entropy();
 
diff --git a/crates/cli/src/commands/templates.rs b/crates/cli/src/commands/templates.rs
index a3a1bf9c..6f09b751 100644
--- a/crates/cli/src/commands/templates.rs
+++ b/crates/cli/src/commands/templates.rs
@@ -14,7 +14,7 @@
 
 use camino::Utf8PathBuf;
 use clap::Parser;
-use mas_storage::Clock;
+use mas_storage::{Clock, SystemClock};
 use mas_templates::Templates;
 use rand::SeedableRng;
 use tracing::info_span;
@@ -41,7 +41,7 @@ impl Options {
             SC::Check { path } => {
                 let _span = info_span!("cli.templates.check").entered();
 
-                let clock = Clock::default();
+                let clock = SystemClock::default();
                 // XXX: we should disallow SeedableRng::from_entropy
                 let mut rng = rand_chacha::ChaChaRng::from_entropy();
                 let url_builder = mas_router::UrlBuilder::new("https://example.com/".parse()?);
diff --git a/crates/handlers/src/compat/login.rs b/crates/handlers/src/compat/login.rs
index bfd36d8a..9b0a0792 100644
--- a/crates/handlers/src/compat/login.rs
+++ b/crates/handlers/src/compat/login.rs
@@ -22,7 +22,7 @@ use mas_storage::{
         CompatSsoLoginRepository,
     },
     user::{UserPasswordRepository, UserRepository},
-    Clock, Repository,
+    Clock, Repository, SystemClock,
 };
 use mas_storage_pg::PgRepository;
 use serde::{Deserialize, Serialize};
@@ -254,7 +254,7 @@ pub(crate) async fn post(
 
 async fn token_login(
     repo: &mut PgRepository,
-    clock: &Clock,
+    clock: &SystemClock,
     token: &str,
 ) -> Result<(CompatSession, User), RouteError> {
     let login = repo
diff --git a/crates/handlers/src/compat/login_sso_complete.rs b/crates/handlers/src/compat/login_sso_complete.rs
index 1fea922e..631d1126 100644
--- a/crates/handlers/src/compat/login_sso_complete.rs
+++ b/crates/handlers/src/compat/login_sso_complete.rs
@@ -31,7 +31,7 @@ use mas_keystore::Encrypter;
 use mas_router::{CompatLoginSsoAction, PostAuthAction, Route};
 use mas_storage::{
     compat::{CompatSessionRepository, CompatSsoLoginRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{CompatSsoContext, ErrorContext, TemplateContext, Templates};
diff --git a/crates/handlers/src/compat/logout.rs b/crates/handlers/src/compat/logout.rs
index 21229fe7..310fef2e 100644
--- a/crates/handlers/src/compat/logout.rs
+++ b/crates/handlers/src/compat/logout.rs
@@ -18,7 +18,7 @@ use hyper::StatusCode;
 use mas_data_model::TokenType;
 use mas_storage::{
     compat::{CompatAccessTokenRepository, CompatSessionRepository},
-    Clock, Repository,
+    Clock, Repository, SystemClock,
 };
 use mas_storage_pg::PgRepository;
 use sqlx::PgPool;
@@ -72,7 +72,7 @@ pub(crate) async fn post(
     State(pool): State<PgPool>,
     maybe_authorization: Option<TypedHeader<Authorization<Bearer>>>,
 ) -> Result<impl IntoResponse, RouteError> {
-    let clock = Clock::default();
+    let clock = SystemClock::default();
     let mut repo = PgRepository::from_pool(&pool).await?;
 
     let TypedHeader(authorization) = maybe_authorization.ok_or(RouteError::MissingAuthorization)?;
diff --git a/crates/handlers/src/compat/refresh.rs b/crates/handlers/src/compat/refresh.rs
index e1601395..8b47a81f 100644
--- a/crates/handlers/src/compat/refresh.rs
+++ b/crates/handlers/src/compat/refresh.rs
@@ -18,7 +18,7 @@ use hyper::StatusCode;
 use mas_data_model::{TokenFormatError, TokenType};
 use mas_storage::{
     compat::{CompatAccessTokenRepository, CompatRefreshTokenRepository, CompatSessionRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use serde::{Deserialize, Serialize};
diff --git a/crates/handlers/src/lib.rs b/crates/handlers/src/lib.rs
index 501f3176..0360e741 100644
--- a/crates/handlers/src/lib.rs
+++ b/crates/handlers/src/lib.rs
@@ -409,8 +409,8 @@ async fn test_state(pool: PgPool) -> Result<AppState, anyhow::Error> {
 }
 
 // XXX: that should be moved somewhere else
-fn clock_and_rng() -> (mas_storage::Clock, rand_chacha::ChaChaRng) {
-    let clock = mas_storage::Clock::default();
+fn clock_and_rng() -> (mas_storage::SystemClock, rand_chacha::ChaChaRng) {
+    let clock = mas_storage::SystemClock::default();
 
     // This rng is used to source the local rng
     #[allow(clippy::disallowed_methods)]
diff --git a/crates/handlers/src/oauth2/consent.rs b/crates/handlers/src/oauth2/consent.rs
index b0f752f7..8fe4d2ac 100644
--- a/crates/handlers/src/oauth2/consent.rs
+++ b/crates/handlers/src/oauth2/consent.rs
@@ -30,7 +30,7 @@ use mas_policy::PolicyFactory;
 use mas_router::{PostAuthAction, Route};
 use mas_storage::{
     oauth2::{OAuth2AuthorizationGrantRepository, OAuth2ClientRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{ConsentContext, PolicyViolationContext, TemplateContext, Templates};
diff --git a/crates/handlers/src/oauth2/introspection.rs b/crates/handlers/src/oauth2/introspection.rs
index e8f9941f..245f2125 100644
--- a/crates/handlers/src/oauth2/introspection.rs
+++ b/crates/handlers/src/oauth2/introspection.rs
@@ -25,7 +25,7 @@ use mas_storage::{
     compat::{CompatAccessTokenRepository, CompatRefreshTokenRepository, CompatSessionRepository},
     oauth2::{OAuth2AccessTokenRepository, OAuth2RefreshTokenRepository, OAuth2SessionRepository},
     user::{BrowserSessionRepository, UserRepository},
-    Clock, Repository,
+    Clock, Repository, SystemClock,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::{
@@ -130,7 +130,7 @@ pub(crate) async fn post(
     State(encrypter): State<Encrypter>,
     client_authorization: ClientAuthorization<IntrospectionRequest>,
 ) -> Result<impl IntoResponse, RouteError> {
-    let clock = Clock::default();
+    let clock = SystemClock::default();
     let mut repo = PgRepository::from_pool(&pool).await?;
 
     let client = client_authorization
diff --git a/crates/handlers/src/oauth2/token.rs b/crates/handlers/src/oauth2/token.rs
index 67ecb498..de0118f4 100644
--- a/crates/handlers/src/oauth2/token.rs
+++ b/crates/handlers/src/oauth2/token.rs
@@ -37,7 +37,7 @@ use mas_storage::{
         OAuth2RefreshTokenRepository, OAuth2SessionRepository,
     },
     user::BrowserSessionRepository,
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::{
diff --git a/crates/handlers/src/oauth2/userinfo.rs b/crates/handlers/src/oauth2/userinfo.rs
index 2f560037..39bc7587 100644
--- a/crates/handlers/src/oauth2/userinfo.rs
+++ b/crates/handlers/src/oauth2/userinfo.rs
@@ -31,7 +31,7 @@ use mas_router::UrlBuilder;
 use mas_storage::{
     oauth2::OAuth2ClientRepository,
     user::{BrowserSessionRepository, UserEmailRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::scope;
diff --git a/crates/handlers/src/upstream_oauth2/authorize.rs b/crates/handlers/src/upstream_oauth2/authorize.rs
index fcf5a7d1..565acea8 100644
--- a/crates/handlers/src/upstream_oauth2/authorize.rs
+++ b/crates/handlers/src/upstream_oauth2/authorize.rs
@@ -24,7 +24,7 @@ use mas_oidc_client::requests::authorization_code::AuthorizationRequestData;
 use mas_router::UrlBuilder;
 use mas_storage::{
     upstream_oauth2::{UpstreamOAuthProviderRepository, UpstreamOAuthSessionRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use sqlx::PgPool;
diff --git a/crates/handlers/src/upstream_oauth2/callback.rs b/crates/handlers/src/upstream_oauth2/callback.rs
index d243666d..ffde4ef3 100644
--- a/crates/handlers/src/upstream_oauth2/callback.rs
+++ b/crates/handlers/src/upstream_oauth2/callback.rs
@@ -30,7 +30,7 @@ use mas_storage::{
         UpstreamOAuthLinkRepository, UpstreamOAuthProviderRepository,
         UpstreamOAuthSessionRepository,
     },
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use oauth2_types::errors::ClientErrorCode;
diff --git a/crates/handlers/src/upstream_oauth2/link.rs b/crates/handlers/src/upstream_oauth2/link.rs
index 8709ff21..c0408770 100644
--- a/crates/handlers/src/upstream_oauth2/link.rs
+++ b/crates/handlers/src/upstream_oauth2/link.rs
@@ -27,7 +27,7 @@ use mas_keystore::Encrypter;
 use mas_storage::{
     upstream_oauth2::{UpstreamOAuthLinkRepository, UpstreamOAuthSessionRepository},
     user::{BrowserSessionRepository, UserRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{
diff --git a/crates/handlers/src/views/account/emails/add.rs b/crates/handlers/src/views/account/emails/add.rs
index e99c8e4d..4c11a485 100644
--- a/crates/handlers/src/views/account/emails/add.rs
+++ b/crates/handlers/src/views/account/emails/add.rs
@@ -24,7 +24,7 @@ use mas_axum_utils::{
 use mas_email::Mailer;
 use mas_keystore::Encrypter;
 use mas_router::Route;
-use mas_storage::{user::UserEmailRepository, Repository};
+use mas_storage::{user::UserEmailRepository, Clock, Repository};
 use mas_storage_pg::PgRepository;
 use mas_templates::{EmailAddContext, TemplateContext, Templates};
 use serde::Deserialize;
diff --git a/crates/handlers/src/views/account/emails/mod.rs b/crates/handlers/src/views/account/emails/mod.rs
index 4d70ab33..f1b7c733 100644
--- a/crates/handlers/src/views/account/emails/mod.rs
+++ b/crates/handlers/src/views/account/emails/mod.rs
@@ -71,7 +71,7 @@ pub(crate) async fn get(
 
 async fn render(
     rng: impl Rng + Send,
-    clock: &Clock,
+    clock: &impl Clock,
     templates: Templates,
     session: BrowserSession,
     cookie_jar: PrivateCookieJar<Encrypter>,
@@ -94,7 +94,7 @@ async fn start_email_verification(
     mailer: &Mailer,
     repo: &mut impl Repository,
     mut rng: impl Rng + Send,
-    clock: &Clock,
+    clock: &impl Clock,
     user: &User,
     user_email: UserEmail,
 ) -> anyhow::Result<()> {
diff --git a/crates/handlers/src/views/account/emails/verify.rs b/crates/handlers/src/views/account/emails/verify.rs
index 2b398b42..f37b15e4 100644
--- a/crates/handlers/src/views/account/emails/verify.rs
+++ b/crates/handlers/src/views/account/emails/verify.rs
@@ -24,7 +24,7 @@ use mas_axum_utils::{
 };
 use mas_keystore::Encrypter;
 use mas_router::Route;
-use mas_storage::{user::UserEmailRepository, Clock, Repository};
+use mas_storage::{user::UserEmailRepository, Clock, Repository, SystemClock};
 use mas_storage_pg::PgRepository;
 use mas_templates::{EmailVerificationPageContext, TemplateContext, Templates};
 use serde::Deserialize;
@@ -89,7 +89,7 @@ pub(crate) async fn post(
     Path(id): Path<Ulid>,
     Form(form): Form<ProtectedForm<CodeForm>>,
 ) -> Result<Response, FancyError> {
-    let clock = Clock::default();
+    let clock = SystemClock::default();
     let mut repo = PgRepository::from_pool(&pool).await?;
 
     let form = cookie_jar.verify_form(clock.now(), form)?;
diff --git a/crates/handlers/src/views/account/mod.rs b/crates/handlers/src/views/account/mod.rs
index 8d2eb3e2..29aaeda3 100644
--- a/crates/handlers/src/views/account/mod.rs
+++ b/crates/handlers/src/views/account/mod.rs
@@ -25,7 +25,7 @@ use mas_keystore::Encrypter;
 use mas_router::Route;
 use mas_storage::{
     user::{BrowserSessionRepository, UserEmailRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{AccountContext, TemplateContext, Templates};
diff --git a/crates/handlers/src/views/account/password.rs b/crates/handlers/src/views/account/password.rs
index 089093f6..1624f6f6 100644
--- a/crates/handlers/src/views/account/password.rs
+++ b/crates/handlers/src/views/account/password.rs
@@ -67,7 +67,7 @@ pub(crate) async fn get(
 
 async fn render(
     rng: impl Rng + Send,
-    clock: &Clock,
+    clock: &impl Clock,
     templates: Templates,
     session: BrowserSession,
     cookie_jar: PrivateCookieJar<Encrypter>,
diff --git a/crates/handlers/src/views/index.rs b/crates/handlers/src/views/index.rs
index cab7c743..2298e83e 100644
--- a/crates/handlers/src/views/index.rs
+++ b/crates/handlers/src/views/index.rs
@@ -20,6 +20,7 @@ use axum_extra::extract::PrivateCookieJar;
 use mas_axum_utils::{csrf::CsrfExt, FancyError, SessionInfoExt};
 use mas_keystore::Encrypter;
 use mas_router::UrlBuilder;
+use mas_storage::Clock;
 use mas_storage_pg::PgRepository;
 use mas_templates::{IndexContext, TemplateContext, Templates};
 use sqlx::PgPool;
diff --git a/crates/handlers/src/views/login.rs b/crates/handlers/src/views/login.rs
index 87ba9e84..10295dbc 100644
--- a/crates/handlers/src/views/login.rs
+++ b/crates/handlers/src/views/login.rs
@@ -167,7 +167,7 @@ async fn login(
     password_manager: PasswordManager,
     repo: &mut impl Repository,
     mut rng: impl Rng + CryptoRng + Send,
-    clock: &Clock,
+    clock: &impl Clock,
     username: &str,
     password: &str,
 ) -> Result<BrowserSession, FormError> {
diff --git a/crates/handlers/src/views/logout.rs b/crates/handlers/src/views/logout.rs
index 373264d0..781780ca 100644
--- a/crates/handlers/src/views/logout.rs
+++ b/crates/handlers/src/views/logout.rs
@@ -23,7 +23,7 @@ use mas_axum_utils::{
 };
 use mas_keystore::Encrypter;
 use mas_router::{PostAuthAction, Route};
-use mas_storage::{user::BrowserSessionRepository, Clock, Repository};
+use mas_storage::{user::BrowserSessionRepository, Clock, Repository, SystemClock};
 use mas_storage_pg::PgRepository;
 use sqlx::PgPool;
 
@@ -32,7 +32,7 @@ pub(crate) async fn post(
     cookie_jar: PrivateCookieJar<Encrypter>,
     Form(form): Form<ProtectedForm<Option<PostAuthAction>>>,
 ) -> Result<impl IntoResponse, FancyError> {
-    let clock = Clock::default();
+    let clock = SystemClock::default();
     let mut repo = PgRepository::from_pool(&pool).await?;
 
     let form = cookie_jar.verify_form(clock.now(), form)?;
diff --git a/crates/handlers/src/views/reauth.rs b/crates/handlers/src/views/reauth.rs
index 49249f3c..571d2e17 100644
--- a/crates/handlers/src/views/reauth.rs
+++ b/crates/handlers/src/views/reauth.rs
@@ -26,7 +26,7 @@ use mas_keystore::Encrypter;
 use mas_router::Route;
 use mas_storage::{
     user::{BrowserSessionRepository, UserPasswordRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{ReauthContext, TemplateContext, Templates};
diff --git a/crates/handlers/src/views/register.rs b/crates/handlers/src/views/register.rs
index 58db6ec1..3e2d87a9 100644
--- a/crates/handlers/src/views/register.rs
+++ b/crates/handlers/src/views/register.rs
@@ -33,7 +33,7 @@ use mas_policy::PolicyFactory;
 use mas_router::Route;
 use mas_storage::{
     user::{BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository},
-    Repository,
+    Clock, Repository,
 };
 use mas_storage_pg::PgRepository;
 use mas_templates::{
diff --git a/crates/storage-pg/src/compat/access_token.rs b/crates/storage-pg/src/compat/access_token.rs
index 5f73ed9e..822c3a8a 100644
--- a/crates/storage-pg/src/compat/access_token.rs
+++ b/crates/storage-pg/src/compat/access_token.rs
@@ -143,7 +143,7 @@ impl<'c> CompatAccessTokenRepository for PgCompatAccessTokenRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: &CompatSession,
         token: String,
         expires_after: Option<Duration>,
@@ -191,7 +191,7 @@ impl<'c> CompatAccessTokenRepository for PgCompatAccessTokenRepository<'c> {
     )]
     async fn expire(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         mut compat_access_token: CompatAccessToken,
     ) -> Result<CompatAccessToken, Self::Error> {
         let expires_at = clock.now();
diff --git a/crates/storage-pg/src/compat/mod.rs b/crates/storage-pg/src/compat/mod.rs
index 732ce3aa..dd68e4d5 100644
--- a/crates/storage-pg/src/compat/mod.rs
+++ b/crates/storage-pg/src/compat/mod.rs
@@ -27,6 +27,7 @@ mod tests {
     use chrono::Duration;
     use mas_data_model::Device;
     use mas_storage::{
+        clock::MockClock,
         compat::{
             CompatAccessTokenRepository, CompatRefreshTokenRepository, CompatSessionRepository,
         },
@@ -44,7 +45,7 @@ mod tests {
         const FIRST_TOKEN: &str = "first_access_token";
         const SECOND_TOKEN: &str = "second_access_token";
         let mut rng = ChaChaRng::seed_from_u64(42);
-        let clock = Clock::mock();
+        let clock = MockClock::default();
         let mut repo = PgRepository::from_pool(&pool).await.unwrap();
 
         // Create a user
@@ -101,7 +102,7 @@ mod tests {
         const FIRST_TOKEN: &str = "first_access_token";
         const SECOND_TOKEN: &str = "second_access_token";
         let mut rng = ChaChaRng::seed_from_u64(42);
-        let clock = Clock::mock();
+        let clock = MockClock::default();
         let mut repo = PgRepository::from_pool(&pool).await.unwrap();
 
         // Create a user
@@ -221,7 +222,7 @@ mod tests {
         const ACCESS_TOKEN: &str = "access_token";
         const REFRESH_TOKEN: &str = "refresh_token";
         let mut rng = ChaChaRng::seed_from_u64(42);
-        let clock = Clock::mock();
+        let clock = MockClock::default();
         let mut repo = PgRepository::from_pool(&pool).await.unwrap();
 
         // Create a user
diff --git a/crates/storage-pg/src/compat/refresh_token.rs b/crates/storage-pg/src/compat/refresh_token.rs
index 314e8147..991e1438 100644
--- a/crates/storage-pg/src/compat/refresh_token.rs
+++ b/crates/storage-pg/src/compat/refresh_token.rs
@@ -154,7 +154,7 @@ impl<'c> CompatRefreshTokenRepository for PgCompatRefreshTokenRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: &CompatSession,
         compat_access_token: &CompatAccessToken,
         token: String,
@@ -202,7 +202,7 @@ impl<'c> CompatRefreshTokenRepository for PgCompatRefreshTokenRepository<'c> {
     )]
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_refresh_token: CompatRefreshToken,
     ) -> Result<CompatRefreshToken, Self::Error> {
         let consumed_at = clock.now();
diff --git a/crates/storage-pg/src/compat/session.rs b/crates/storage-pg/src/compat/session.rs
index a6e65f9a..16208b4f 100644
--- a/crates/storage-pg/src/compat/session.rs
+++ b/crates/storage-pg/src/compat/session.rs
@@ -122,7 +122,7 @@ impl<'c> CompatSessionRepository for PgCompatSessionRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         device: Device,
     ) -> Result<CompatSession, Self::Error> {
@@ -166,7 +166,7 @@ impl<'c> CompatSessionRepository for PgCompatSessionRepository<'c> {
     )]
     async fn finish(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: CompatSession,
     ) -> Result<CompatSession, Self::Error> {
         let finished_at = clock.now();
diff --git a/crates/storage-pg/src/compat/sso_login.rs b/crates/storage-pg/src/compat/sso_login.rs
index a2eeb926..1b8e0225 100644
--- a/crates/storage-pg/src/compat/sso_login.rs
+++ b/crates/storage-pg/src/compat/sso_login.rs
@@ -177,7 +177,7 @@ impl<'c> CompatSsoLoginRepository for PgCompatSsoLoginRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         login_token: String,
         redirect_uri: Url,
     ) -> Result<CompatSsoLogin, Self::Error> {
@@ -223,7 +223,7 @@ impl<'c> CompatSsoLoginRepository for PgCompatSsoLoginRepository<'c> {
     )]
     async fn fulfill(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_sso_login: CompatSsoLogin,
         compat_session: &CompatSession,
     ) -> Result<CompatSsoLogin, Self::Error> {
@@ -265,7 +265,7 @@ impl<'c> CompatSsoLoginRepository for PgCompatSsoLoginRepository<'c> {
     )]
     async fn exchange(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_sso_login: CompatSsoLogin,
     ) -> Result<CompatSsoLogin, Self::Error> {
         let exchanged_at = clock.now();
diff --git a/crates/storage-pg/src/oauth2/access_token.rs b/crates/storage-pg/src/oauth2/access_token.rs
index 33d95242..ecd5798b 100644
--- a/crates/storage-pg/src/oauth2/access_token.rs
+++ b/crates/storage-pg/src/oauth2/access_token.rs
@@ -142,7 +142,7 @@ impl<'c> OAuth2AccessTokenRepository for PgOAuth2AccessTokenRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         access_token: String,
         expires_after: Duration,
@@ -182,7 +182,7 @@ impl<'c> OAuth2AccessTokenRepository for PgOAuth2AccessTokenRepository<'c> {
 
     async fn revoke(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         access_token: AccessToken,
     ) -> Result<AccessToken, Self::Error> {
         let revoked_at = clock.now();
@@ -205,7 +205,7 @@ impl<'c> OAuth2AccessTokenRepository for PgOAuth2AccessTokenRepository<'c> {
             .map_err(DatabaseError::to_invalid_operation)
     }
 
-    async fn cleanup_expired(&mut self, clock: &Clock) -> Result<usize, Self::Error> {
+    async fn cleanup_expired(&mut self, clock: &dyn Clock) -> Result<usize, Self::Error> {
         // Cleanup token which expired more than 15 minutes ago
         let threshold = clock.now() - Duration::minutes(15);
         let res = sqlx::query!(
diff --git a/crates/storage-pg/src/oauth2/authorization_grant.rs b/crates/storage-pg/src/oauth2/authorization_grant.rs
index 027111a7..92116a62 100644
--- a/crates/storage-pg/src/oauth2/authorization_grant.rs
+++ b/crates/storage-pg/src/oauth2/authorization_grant.rs
@@ -211,7 +211,7 @@ impl<'c> OAuth2AuthorizationGrantRepository for PgOAuth2AuthorizationGrantReposi
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         client: &Client,
         redirect_uri: Url,
         scope: Scope,
@@ -410,7 +410,7 @@ impl<'c> OAuth2AuthorizationGrantRepository for PgOAuth2AuthorizationGrantReposi
     )]
     async fn fulfill(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         grant: AuthorizationGrant,
     ) -> Result<AuthorizationGrant, Self::Error> {
@@ -451,7 +451,7 @@ impl<'c> OAuth2AuthorizationGrantRepository for PgOAuth2AuthorizationGrantReposi
     )]
     async fn exchange(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         grant: AuthorizationGrant,
     ) -> Result<AuthorizationGrant, Self::Error> {
         let exchanged_at = clock.now();
diff --git a/crates/storage-pg/src/oauth2/client.rs b/crates/storage-pg/src/oauth2/client.rs
index 4430c669..1b8a99f9 100644
--- a/crates/storage-pg/src/oauth2/client.rs
+++ b/crates/storage-pg/src/oauth2/client.rs
@@ -378,7 +378,7 @@ impl<'c> OAuth2ClientRepository for PgOAuth2ClientRepository<'c> {
     async fn add(
         &mut self,
         mut rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         redirect_uris: Vec<Url>,
         encrypted_client_secret: Option<String>,
         grant_types: Vec<GrantType>,
@@ -535,7 +535,7 @@ impl<'c> OAuth2ClientRepository for PgOAuth2ClientRepository<'c> {
     async fn add_from_config(
         &mut self,
         mut rng: impl Rng + Send,
-        clock: &Clock,
+        clock: &dyn Clock,
         client_id: Ulid,
         client_auth_method: OAuthClientAuthenticationMethod,
         encrypted_client_secret: Option<String>,
@@ -707,7 +707,7 @@ impl<'c> OAuth2ClientRepository for PgOAuth2ClientRepository<'c> {
     async fn give_consent_for_user(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         client: &Client,
         user: &User,
         scope: &Scope,
diff --git a/crates/storage-pg/src/oauth2/refresh_token.rs b/crates/storage-pg/src/oauth2/refresh_token.rs
index 47281d93..ba2fa533 100644
--- a/crates/storage-pg/src/oauth2/refresh_token.rs
+++ b/crates/storage-pg/src/oauth2/refresh_token.rs
@@ -150,7 +150,7 @@ impl<'c> OAuth2RefreshTokenRepository for PgOAuth2RefreshTokenRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         access_token: &AccessToken,
         refresh_token: String,
@@ -199,7 +199,7 @@ impl<'c> OAuth2RefreshTokenRepository for PgOAuth2RefreshTokenRepository<'c> {
     )]
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         refresh_token: RefreshToken,
     ) -> Result<RefreshToken, Self::Error> {
         let consumed_at = clock.now();
diff --git a/crates/storage-pg/src/oauth2/session.rs b/crates/storage-pg/src/oauth2/session.rs
index 96f798e6..f1c41279 100644
--- a/crates/storage-pg/src/oauth2/session.rs
+++ b/crates/storage-pg/src/oauth2/session.rs
@@ -131,7 +131,7 @@ impl<'c> OAuth2SessionRepository for PgOAuth2SessionRepository<'c> {
     async fn create_from_grant(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         grant: &AuthorizationGrant,
         user_session: &BrowserSession,
     ) -> Result<Session, Self::Error> {
@@ -182,7 +182,7 @@ impl<'c> OAuth2SessionRepository for PgOAuth2SessionRepository<'c> {
         ),
         err,
     )]
-    async fn finish(&mut self, clock: &Clock, session: Session) -> Result<Session, Self::Error> {
+    async fn finish(&mut self, clock: &dyn Clock, session: Session) -> Result<Session, Self::Error> {
         let finished_at = clock.now();
         let res = sqlx::query!(
             r#"
diff --git a/crates/storage-pg/src/upstream_oauth2/link.rs b/crates/storage-pg/src/upstream_oauth2/link.rs
index 4087e2c7..c38b344b 100644
--- a/crates/storage-pg/src/upstream_oauth2/link.rs
+++ b/crates/storage-pg/src/upstream_oauth2/link.rs
@@ -149,7 +149,7 @@ impl<'c> UpstreamOAuthLinkRepository for PgUpstreamOAuthLinkRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_provider: &UpstreamOAuthProvider,
         subject: String,
     ) -> Result<UpstreamOAuthLink, Self::Error> {
diff --git a/crates/storage-pg/src/upstream_oauth2/mod.rs b/crates/storage-pg/src/upstream_oauth2/mod.rs
index e77daba2..af631f15 100644
--- a/crates/storage-pg/src/upstream_oauth2/mod.rs
+++ b/crates/storage-pg/src/upstream_oauth2/mod.rs
@@ -25,12 +25,13 @@ pub use self::{
 mod tests {
     use chrono::Duration;
     use mas_storage::{
+        clock::MockClock,
         upstream_oauth2::{
             UpstreamOAuthLinkRepository, UpstreamOAuthProviderRepository,
             UpstreamOAuthSessionRepository,
         },
         user::UserRepository,
-        Clock, Pagination, Repository,
+        Pagination, Repository,
     };
     use oauth2_types::scope::{Scope, OPENID};
     use rand::SeedableRng;
@@ -41,7 +42,7 @@ mod tests {
     #[sqlx::test(migrator = "crate::MIGRATOR")]
     async fn test_repository(pool: PgPool) {
         let mut rng = rand_chacha::ChaChaRng::seed_from_u64(42);
-        let clock = Clock::mock();
+        let clock = MockClock::default();
         let mut repo = PgRepository::from_pool(&pool).await.unwrap();
 
         // The provider list should be empty at the start
@@ -183,7 +184,7 @@ mod tests {
         let scope = Scope::from_iter([OPENID]);
 
         let mut rng = rand_chacha::ChaChaRng::seed_from_u64(42);
-        let clock = Clock::mock();
+        let clock = MockClock::default();
         let mut repo = PgRepository::from_pool(&pool).await.unwrap();
 
         let mut ids = Vec::with_capacity(20);
diff --git a/crates/storage-pg/src/upstream_oauth2/provider.rs b/crates/storage-pg/src/upstream_oauth2/provider.rs
index 480249ee..dc1b0c85 100644
--- a/crates/storage-pg/src/upstream_oauth2/provider.rs
+++ b/crates/storage-pg/src/upstream_oauth2/provider.rs
@@ -149,7 +149,7 @@ impl<'c> UpstreamOAuthProviderRepository for PgUpstreamOAuthProviderRepository<'
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         issuer: String,
         scope: Scope,
         token_endpoint_auth_method: OAuthClientAuthenticationMethod,
diff --git a/crates/storage-pg/src/upstream_oauth2/session.rs b/crates/storage-pg/src/upstream_oauth2/session.rs
index 699a463f..3cdef0c7 100644
--- a/crates/storage-pg/src/upstream_oauth2/session.rs
+++ b/crates/storage-pg/src/upstream_oauth2/session.rs
@@ -156,7 +156,7 @@ impl<'c> UpstreamOAuthSessionRepository for PgUpstreamOAuthSessionRepository<'c>
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_provider: &UpstreamOAuthProvider,
         state_str: String,
         code_challenge_verifier: Option<String>,
@@ -217,7 +217,7 @@ impl<'c> UpstreamOAuthSessionRepository for PgUpstreamOAuthSessionRepository<'c>
     )]
     async fn complete_with_link(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_authorization_session: UpstreamOAuthAuthorizationSession,
         upstream_oauth_link: &UpstreamOAuthLink,
         id_token: Option<String>,
@@ -260,7 +260,7 @@ impl<'c> UpstreamOAuthSessionRepository for PgUpstreamOAuthSessionRepository<'c>
     )]
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_authorization_session: UpstreamOAuthAuthorizationSession,
     ) -> Result<UpstreamOAuthAuthorizationSession, Self::Error> {
         let consumed_at = clock.now();
diff --git a/crates/storage-pg/src/user/email.rs b/crates/storage-pg/src/user/email.rs
index 936b0649..b9d732de 100644
--- a/crates/storage-pg/src/user/email.rs
+++ b/crates/storage-pg/src/user/email.rs
@@ -68,7 +68,7 @@ struct UserEmailConfirmationCodeLookup {
 }
 
 impl UserEmailConfirmationCodeLookup {
-    fn into_verification(self, clock: &Clock) -> UserEmailVerification {
+    fn into_verification(self, clock: &dyn Clock) -> UserEmailVerification {
         let now = clock.now();
         let state = if let Some(when) = self.consumed_at {
             UserEmailVerificationState::AlreadyUsed { when }
@@ -301,7 +301,7 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         email: String,
     ) -> Result<UserEmail, Self::Error> {
@@ -378,7 +378,7 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
 
     async fn mark_as_verified(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         mut user_email: UserEmail,
     ) -> Result<UserEmail, Self::Error> {
         let confirmed_at = clock.now();
@@ -430,7 +430,7 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
     async fn add_verification_code(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user_email: &UserEmail,
         max_age: chrono::Duration,
         code: String,
@@ -479,7 +479,7 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
     )]
     async fn find_verification_code(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         user_email: &UserEmail,
         code: &str,
     ) -> Result<Option<UserEmailVerification>, Self::Error> {
@@ -521,7 +521,7 @@ impl<'c> UserEmailRepository for PgUserEmailRepository<'c> {
     )]
     async fn consume_verification_code(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         mut user_email_verification: UserEmailVerification,
     ) -> Result<UserEmailVerification, Self::Error> {
         if !matches!(
diff --git a/crates/storage-pg/src/user/mod.rs b/crates/storage-pg/src/user/mod.rs
index d7320261..8ec6170f 100644
--- a/crates/storage-pg/src/user/mod.rs
+++ b/crates/storage-pg/src/user/mod.rs
@@ -148,7 +148,7 @@ impl<'c> UserRepository for PgUserRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         username: String,
     ) -> Result<User, Self::Error> {
         let created_at = clock.now();
diff --git a/crates/storage-pg/src/user/password.rs b/crates/storage-pg/src/user/password.rs
index 997b1227..696b30e7 100644
--- a/crates/storage-pg/src/user/password.rs
+++ b/crates/storage-pg/src/user/password.rs
@@ -115,7 +115,7 @@ impl<'c> UserPasswordRepository for PgUserPasswordRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         version: u16,
         hashed_password: String,
diff --git a/crates/storage-pg/src/user/session.rs b/crates/storage-pg/src/user/session.rs
index d216c067..e5616fff 100644
--- a/crates/storage-pg/src/user/session.rs
+++ b/crates/storage-pg/src/user/session.rs
@@ -142,7 +142,7 @@ impl<'c> BrowserSessionRepository for PgBrowserSessionRepository<'c> {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
     ) -> Result<BrowserSession, Self::Error> {
         let created_at = clock.now();
@@ -185,7 +185,7 @@ impl<'c> BrowserSessionRepository for PgBrowserSessionRepository<'c> {
     )]
     async fn finish(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         mut user_session: BrowserSession,
     ) -> Result<BrowserSession, Self::Error> {
         let finished_at = clock.now();
@@ -297,7 +297,7 @@ impl<'c> BrowserSessionRepository for PgBrowserSessionRepository<'c> {
     async fn authenticate_with_password(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         mut user_session: BrowserSession,
         user_password: &Password,
     ) -> Result<BrowserSession, Self::Error> {
@@ -342,7 +342,7 @@ impl<'c> BrowserSessionRepository for PgBrowserSessionRepository<'c> {
     async fn authenticate_with_upstream(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         mut user_session: BrowserSession,
         upstream_oauth_link: &UpstreamOAuthLink,
     ) -> Result<BrowserSession, Self::Error> {
diff --git a/crates/storage-pg/src/user/tests.rs b/crates/storage-pg/src/user/tests.rs
index f0a071b0..097bca74 100644
--- a/crates/storage-pg/src/user/tests.rs
+++ b/crates/storage-pg/src/user/tests.rs
@@ -14,8 +14,9 @@
 
 use chrono::Duration;
 use mas_storage::{
+    clock::MockClock,
     user::{BrowserSessionRepository, UserEmailRepository, UserPasswordRepository, UserRepository},
-    Clock, Repository,
+    Repository,
 };
 use rand::SeedableRng;
 use rand_chacha::ChaChaRng;
@@ -30,7 +31,7 @@ async fn test_user_repo(pool: PgPool) {
 
     let mut repo = PgRepository::from_pool(&pool).await.unwrap();
     let mut rng = ChaChaRng::seed_from_u64(42);
-    let clock = Clock::mock();
+    let clock = MockClock::default();
 
     // Initially, the user shouldn't exist
     assert!(!repo.user().exists(USERNAME).await.unwrap());
@@ -78,7 +79,7 @@ async fn test_user_email_repo(pool: PgPool) {
 
     let mut repo = PgRepository::from_pool(&pool).await.unwrap();
     let mut rng = ChaChaRng::seed_from_u64(42);
-    let clock = Clock::mock();
+    let clock = MockClock::default();
 
     let user = repo
         .user()
@@ -89,7 +90,7 @@ async fn test_user_email_repo(pool: PgPool) {
     // The user email should not exist yet
     assert!(repo
         .user_email()
-        .find(&user, EMAIL)
+        .find(&user, &EMAIL)
         .await
         .unwrap()
         .is_none());
@@ -110,7 +111,7 @@ async fn test_user_email_repo(pool: PgPool) {
 
     assert!(repo
         .user_email()
-        .find(&user, EMAIL)
+        .find(&user, &EMAIL)
         .await
         .unwrap()
         .is_some());
@@ -180,7 +181,7 @@ async fn test_user_email_repo(pool: PgPool) {
     // Reload the user_email
     let user_email = repo
         .user_email()
-        .find(&user, EMAIL)
+        .find(&user, &EMAIL)
         .await
         .unwrap()
         .expect("user email was not found");
@@ -260,7 +261,7 @@ async fn test_user_password_repo(pool: PgPool) {
 
     let mut repo = PgRepository::from_pool(&pool).await.unwrap();
     let mut rng = ChaChaRng::seed_from_u64(42);
-    let clock = Clock::mock();
+    let clock = MockClock::default();
 
     let user = repo
         .user()
@@ -340,7 +341,7 @@ async fn test_user_session(pool: PgPool) {
 
     let mut repo = PgRepository::from_pool(&pool).await.unwrap();
     let mut rng = ChaChaRng::seed_from_u64(42);
-    let clock = Clock::mock();
+    let clock = MockClock::default();
 
     let user = repo
         .user()
diff --git a/crates/storage/src/clock.rs b/crates/storage/src/clock.rs
new file mode 100644
index 00000000..54ca3b4f
--- /dev/null
+++ b/crates/storage/src/clock.rs
@@ -0,0 +1,129 @@
+// Copyright 2023 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! A [`Clock`] is a way to get the current date and time.
+//!
+//! This module defines two implemetation of the [`Clock`] trait:
+//! [`SystemClock`] which uses the system time, and a [`MockClock`], which can
+//! be used and freely manipulated in tests.
+
+use std::sync::atomic::AtomicI64;
+
+use chrono::{DateTime, TimeZone, Utc};
+
+/// Represents a clock which can give the current date and time
+pub trait Clock: Sync {
+    /// Get the current date and time
+    fn now(&self) -> DateTime<Utc>;
+}
+
+/// A clock which uses the system time
+#[derive(Clone, Default)]
+pub struct SystemClock {
+    _private: (),
+}
+
+impl Clock for SystemClock {
+    fn now(&self) -> DateTime<Utc> {
+        // This is the clock used elsewhere, it's fine to call Utc::now here
+        #[allow(clippy::disallowed_methods)]
+        Utc::now()
+    }
+}
+
+/// A fake clock, which uses a fixed timestamp, and can be advanced with the
+/// [`MockClock::advance`] method.
+///
+/// ```rust
+/// use mas_storage::clock::{Clock, MockClock};
+/// use chrono::Duration;
+///
+/// let clock = MockClock::default();
+/// let t1 = clock.now();
+/// let t2 = clock.now();
+/// assert_eq!(t1, t2);
+///
+/// clock.advance(Duration::seconds(10));
+/// let t3 = clock.now();
+/// assert_eq!(t2 + Duration::seconds(10), t3);
+/// ```
+pub struct MockClock {
+    timestamp: AtomicI64,
+}
+
+impl Default for MockClock {
+    fn default() -> Self {
+        let datetime = Utc.with_ymd_and_hms(2022, 1, 16, 14, 40, 0).unwrap();
+        Self::new(datetime)
+    }
+}
+
+impl MockClock {
+    /// Create a new clock which starts at the given datetime
+    #[must_use]
+    pub fn new(datetime: DateTime<Utc>) -> Self {
+        let timestamp = AtomicI64::new(datetime.timestamp());
+        Self { timestamp }
+    }
+
+    /// Move the clock forward by the given amount of time
+    pub fn advance(&self, duration: chrono::Duration) {
+        self.timestamp
+            .fetch_add(duration.num_seconds(), std::sync::atomic::Ordering::Relaxed);
+    }
+}
+
+impl Clock for MockClock {
+    fn now(&self) -> DateTime<Utc> {
+        let timestamp = self.timestamp.load(std::sync::atomic::Ordering::Relaxed);
+        chrono::TimeZone::timestamp_opt(&Utc, timestamp, 0).unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use chrono::Duration;
+
+    use super::*;
+
+    #[test]
+    fn test_mocked_clock() {
+        let clock = MockClock::default();
+
+        // Time should be frozen, and give out the same timestamp on each call
+        let first = clock.now();
+        std::thread::sleep(std::time::Duration::from_millis(10));
+        let second = clock.now();
+
+        assert_eq!(first, second);
+
+        // Clock can be advanced by a fixed duration
+        clock.advance(Duration::seconds(10));
+        let third = clock.now();
+        assert_eq!(first + Duration::seconds(10), third);
+    }
+
+    #[test]
+    fn test_real_clock() {
+        let clock = SystemClock::default();
+
+        // Time should not be frozen
+        let first = clock.now();
+        std::thread::sleep(std::time::Duration::from_millis(10));
+        let second = clock.now();
+
+        assert_ne!(first, second);
+        assert!(first < second);
+    }
+}
diff --git a/crates/storage/src/compat/access_token.rs b/crates/storage/src/compat/access_token.rs
index 46ff6e3f..e135be39 100644
--- a/crates/storage/src/compat/access_token.rs
+++ b/crates/storage/src/compat/access_token.rs
@@ -37,7 +37,7 @@ pub trait CompatAccessTokenRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: &CompatSession,
         token: String,
         expires_after: Option<Duration>,
@@ -46,7 +46,7 @@ pub trait CompatAccessTokenRepository: Send + Sync {
     /// Set the expiration time of the compat access token to now
     async fn expire(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_access_token: CompatAccessToken,
     ) -> Result<CompatAccessToken, Self::Error>;
 }
diff --git a/crates/storage/src/compat/refresh_token.rs b/crates/storage/src/compat/refresh_token.rs
index 7a1057ff..f8e8dfaa 100644
--- a/crates/storage/src/compat/refresh_token.rs
+++ b/crates/storage/src/compat/refresh_token.rs
@@ -36,7 +36,7 @@ pub trait CompatRefreshTokenRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: &CompatSession,
         compat_access_token: &CompatAccessToken,
         token: String,
@@ -45,7 +45,7 @@ pub trait CompatRefreshTokenRepository: Send + Sync {
     /// Consume a compat refresh token
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_refresh_token: CompatRefreshToken,
     ) -> Result<CompatRefreshToken, Self::Error>;
 }
diff --git a/crates/storage/src/compat/session.rs b/crates/storage/src/compat/session.rs
index 34bc6838..fa5cbd6e 100644
--- a/crates/storage/src/compat/session.rs
+++ b/crates/storage/src/compat/session.rs
@@ -30,7 +30,7 @@ pub trait CompatSessionRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         device: Device,
     ) -> Result<CompatSession, Self::Error>;
@@ -38,7 +38,7 @@ pub trait CompatSessionRepository: Send + Sync {
     /// End a compat session
     async fn finish(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_session: CompatSession,
     ) -> Result<CompatSession, Self::Error>;
 }
diff --git a/crates/storage/src/compat/sso_login.rs b/crates/storage/src/compat/sso_login.rs
index 348e0ac5..6ee3270a 100644
--- a/crates/storage/src/compat/sso_login.rs
+++ b/crates/storage/src/compat/sso_login.rs
@@ -37,7 +37,7 @@ pub trait CompatSsoLoginRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         login_token: String,
         redirect_uri: Url,
     ) -> Result<CompatSsoLogin, Self::Error>;
@@ -45,7 +45,7 @@ pub trait CompatSsoLoginRepository: Send + Sync {
     /// Fulfill a compat SSO login by providing a compat session
     async fn fulfill(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_sso_login: CompatSsoLogin,
         compat_session: &CompatSession,
     ) -> Result<CompatSsoLogin, Self::Error>;
@@ -53,7 +53,7 @@ pub trait CompatSsoLoginRepository: Send + Sync {
     /// Mark a compat SSO login as exchanged
     async fn exchange(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         compat_sso_login: CompatSsoLogin,
     ) -> Result<CompatSsoLogin, Self::Error>;
 
diff --git a/crates/storage/src/lib.rs b/crates/storage/src/lib.rs
index a65c806c..2a83b55e 100644
--- a/crates/storage/src/lib.rs
+++ b/crates/storage/src/lib.rs
@@ -28,92 +28,7 @@
     clippy::module_name_repetitions
 )]
 
-use chrono::{DateTime, Utc};
-
-#[derive(Debug, Clone, Default)]
-pub struct Clock {
-    _private: (),
-
-    // #[cfg(test)]
-    mock: Option<std::sync::Arc<std::sync::atomic::AtomicI64>>,
-}
-
-impl Clock {
-    #[must_use]
-    pub fn now(&self) -> DateTime<Utc> {
-        // #[cfg(test)]
-        if let Some(timestamp) = &self.mock {
-            let timestamp = timestamp.load(std::sync::atomic::Ordering::Relaxed);
-            return chrono::TimeZone::timestamp_opt(&Utc, timestamp, 0).unwrap();
-        }
-
-        // This is the clock used elsewhere, it's fine to call Utc::now here
-        #[allow(clippy::disallowed_methods)]
-        Utc::now()
-    }
-
-    // #[cfg(test)]
-    #[must_use]
-    pub fn mock() -> Self {
-        use std::sync::{atomic::AtomicI64, Arc};
-
-        use chrono::TimeZone;
-
-        let datetime = Utc.with_ymd_and_hms(2022, 1, 16, 14, 40, 0).unwrap();
-        let timestamp = datetime.timestamp();
-
-        Self {
-            mock: Some(Arc::new(AtomicI64::new(timestamp))),
-            _private: (),
-        }
-    }
-
-    // #[cfg(test)]
-    pub fn advance(&self, duration: chrono::Duration) {
-        let timestamp = self
-            .mock
-            .as_ref()
-            .expect("Clock::advance should only be called on mocked clocks in tests");
-        timestamp.fetch_add(duration.num_seconds(), std::sync::atomic::Ordering::Relaxed);
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use chrono::Duration;
-
-    use super::*;
-
-    #[test]
-    fn test_mocked_clock() {
-        let clock = Clock::mock();
-
-        // Time should be frozen, and give out the same timestamp on each call
-        let first = clock.now();
-        std::thread::sleep(std::time::Duration::from_millis(10));
-        let second = clock.now();
-
-        assert_eq!(first, second);
-
-        // Clock can be advanced by a fixed duration
-        clock.advance(Duration::seconds(10));
-        let third = clock.now();
-        assert_eq!(first + Duration::seconds(10), third);
-    }
-
-    #[test]
-    fn test_real_clock() {
-        let clock = Clock::default();
-
-        // Time should not be frozen
-        let first = clock.now();
-        std::thread::sleep(std::time::Duration::from_millis(10));
-        let second = clock.now();
-
-        assert_ne!(first, second);
-        assert!(first < second);
-    }
-}
+pub mod clock;
 
 pub mod compat;
 pub mod oauth2;
@@ -123,6 +38,7 @@ pub mod upstream_oauth2;
 pub mod user;
 
 pub use self::{
+    clock::{Clock, SystemClock},
     pagination::{Page, Pagination},
     repository::Repository,
 };
diff --git a/crates/storage/src/oauth2/access_token.rs b/crates/storage/src/oauth2/access_token.rs
index a0406e44..4bbcf885 100644
--- a/crates/storage/src/oauth2/access_token.rs
+++ b/crates/storage/src/oauth2/access_token.rs
@@ -37,7 +37,7 @@ pub trait OAuth2AccessTokenRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         access_token: String,
         expires_after: Duration,
@@ -46,10 +46,10 @@ pub trait OAuth2AccessTokenRepository: Send + Sync {
     /// Revoke an access token
     async fn revoke(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         access_token: AccessToken,
     ) -> Result<AccessToken, Self::Error>;
 
     /// Cleanup expired access tokens
-    async fn cleanup_expired(&mut self, clock: &Clock) -> Result<usize, Self::Error>;
+    async fn cleanup_expired(&mut self, clock: &dyn Clock) -> Result<usize, Self::Error>;
 }
diff --git a/crates/storage/src/oauth2/authorization_grant.rs b/crates/storage/src/oauth2/authorization_grant.rs
index ce1a716f..96403f12 100644
--- a/crates/storage/src/oauth2/authorization_grant.rs
+++ b/crates/storage/src/oauth2/authorization_grant.rs
@@ -31,7 +31,7 @@ pub trait OAuth2AuthorizationGrantRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         client: &Client,
         redirect_uri: Url,
         scope: Scope,
@@ -51,14 +51,14 @@ pub trait OAuth2AuthorizationGrantRepository: Send + Sync {
 
     async fn fulfill(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         authorization_grant: AuthorizationGrant,
     ) -> Result<AuthorizationGrant, Self::Error>;
 
     async fn exchange(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         authorization_grant: AuthorizationGrant,
     ) -> Result<AuthorizationGrant, Self::Error>;
 
diff --git a/crates/storage/src/oauth2/client.rs b/crates/storage/src/oauth2/client.rs
index 093369a4..30f37bc6 100644
--- a/crates/storage/src/oauth2/client.rs
+++ b/crates/storage/src/oauth2/client.rs
@@ -45,7 +45,7 @@ pub trait OAuth2ClientRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         redirect_uris: Vec<Url>,
         encrypted_client_secret: Option<String>,
         grant_types: Vec<GrantType>,
@@ -68,7 +68,7 @@ pub trait OAuth2ClientRepository: Send + Sync {
     async fn add_from_config(
         &mut self,
         mut rng: impl Rng + Send,
-        clock: &Clock,
+        clock: &dyn Clock,
         client_id: Ulid,
         client_auth_method: OAuthClientAuthenticationMethod,
         encrypted_client_secret: Option<String>,
@@ -86,7 +86,7 @@ pub trait OAuth2ClientRepository: Send + Sync {
     async fn give_consent_for_user(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         client: &Client,
         user: &User,
         scope: &Scope,
diff --git a/crates/storage/src/oauth2/refresh_token.rs b/crates/storage/src/oauth2/refresh_token.rs
index 1e23634a..88bb26fb 100644
--- a/crates/storage/src/oauth2/refresh_token.rs
+++ b/crates/storage/src/oauth2/refresh_token.rs
@@ -36,7 +36,7 @@ pub trait OAuth2RefreshTokenRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         session: &Session,
         access_token: &AccessToken,
         refresh_token: String,
@@ -45,7 +45,7 @@ pub trait OAuth2RefreshTokenRepository: Send + Sync {
     /// Consume a refresh token
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         refresh_token: RefreshToken,
     ) -> Result<RefreshToken, Self::Error>;
 }
diff --git a/crates/storage/src/oauth2/session.rs b/crates/storage/src/oauth2/session.rs
index 5e6498d8..944c7784 100644
--- a/crates/storage/src/oauth2/session.rs
+++ b/crates/storage/src/oauth2/session.rs
@@ -28,12 +28,12 @@ pub trait OAuth2SessionRepository: Send + Sync {
     async fn create_from_grant(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         grant: &AuthorizationGrant,
         user_session: &BrowserSession,
     ) -> Result<Session, Self::Error>;
 
-    async fn finish(&mut self, clock: &Clock, session: Session) -> Result<Session, Self::Error>;
+    async fn finish(&mut self, clock: &dyn Clock, session: Session) -> Result<Session, Self::Error>;
 
     async fn list_paginated(
         &mut self,
diff --git a/crates/storage/src/upstream_oauth2/link.rs b/crates/storage/src/upstream_oauth2/link.rs
index bc20c6ea..474c21d9 100644
--- a/crates/storage/src/upstream_oauth2/link.rs
+++ b/crates/storage/src/upstream_oauth2/link.rs
@@ -37,7 +37,7 @@ pub trait UpstreamOAuthLinkRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_provider: &UpstreamOAuthProvider,
         subject: String,
     ) -> Result<UpstreamOAuthLink, Self::Error>;
diff --git a/crates/storage/src/upstream_oauth2/provider.rs b/crates/storage/src/upstream_oauth2/provider.rs
index 4be8f127..10a03e2b 100644
--- a/crates/storage/src/upstream_oauth2/provider.rs
+++ b/crates/storage/src/upstream_oauth2/provider.rs
@@ -33,7 +33,7 @@ pub trait UpstreamOAuthProviderRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         issuer: String,
         scope: Scope,
         token_endpoint_auth_method: OAuthClientAuthenticationMethod,
diff --git a/crates/storage/src/upstream_oauth2/session.rs b/crates/storage/src/upstream_oauth2/session.rs
index 4d41a8ec..e1b6abc1 100644
--- a/crates/storage/src/upstream_oauth2/session.rs
+++ b/crates/storage/src/upstream_oauth2/session.rs
@@ -33,7 +33,7 @@ pub trait UpstreamOAuthSessionRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_provider: &UpstreamOAuthProvider,
         state: String,
         code_challenge_verifier: Option<String>,
@@ -43,7 +43,7 @@ pub trait UpstreamOAuthSessionRepository: Send + Sync {
     /// Mark a session as completed and associate the given link
     async fn complete_with_link(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_authorization_session: UpstreamOAuthAuthorizationSession,
         upstream_oauth_link: &UpstreamOAuthLink,
         id_token: Option<String>,
@@ -52,7 +52,7 @@ pub trait UpstreamOAuthSessionRepository: Send + Sync {
     /// Mark a session as consumed
     async fn consume(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         upstream_oauth_authorization_session: UpstreamOAuthAuthorizationSession,
     ) -> Result<UpstreamOAuthAuthorizationSession, Self::Error>;
 }
diff --git a/crates/storage/src/user/email.rs b/crates/storage/src/user/email.rs
index 41a7d293..4b8f846d 100644
--- a/crates/storage/src/user/email.rs
+++ b/crates/storage/src/user/email.rs
@@ -38,7 +38,7 @@ pub trait UserEmailRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         email: String,
     ) -> Result<UserEmail, Self::Error>;
@@ -46,7 +46,7 @@ pub trait UserEmailRepository: Send + Sync {
 
     async fn mark_as_verified(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         user_email: UserEmail,
     ) -> Result<UserEmail, Self::Error>;
 
@@ -55,7 +55,7 @@ pub trait UserEmailRepository: Send + Sync {
     async fn add_verification_code(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user_email: &UserEmail,
         max_age: chrono::Duration,
         code: String,
@@ -63,14 +63,14 @@ pub trait UserEmailRepository: Send + Sync {
 
     async fn find_verification_code(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         user_email: &UserEmail,
         code: &str,
     ) -> Result<Option<UserEmailVerification>, Self::Error>;
 
     async fn consume_verification_code(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         verification: UserEmailVerification,
     ) -> Result<UserEmailVerification, Self::Error>;
 }
diff --git a/crates/storage/src/user/mod.rs b/crates/storage/src/user/mod.rs
index 23c2f6d1..8e046a9d 100644
--- a/crates/storage/src/user/mod.rs
+++ b/crates/storage/src/user/mod.rs
@@ -36,7 +36,7 @@ pub trait UserRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         username: String,
     ) -> Result<User, Self::Error>;
     async fn exists(&mut self, username: &str) -> Result<bool, Self::Error>;
diff --git a/crates/storage/src/user/password.rs b/crates/storage/src/user/password.rs
index 2d2d2534..306f7d93 100644
--- a/crates/storage/src/user/password.rs
+++ b/crates/storage/src/user/password.rs
@@ -26,7 +26,7 @@ pub trait UserPasswordRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
         version: u16,
         hashed_password: String,
diff --git a/crates/storage/src/user/session.rs b/crates/storage/src/user/session.rs
index 2e55f40c..5499f45a 100644
--- a/crates/storage/src/user/session.rs
+++ b/crates/storage/src/user/session.rs
@@ -27,12 +27,12 @@ pub trait BrowserSessionRepository: Send + Sync {
     async fn add(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user: &User,
     ) -> Result<BrowserSession, Self::Error>;
     async fn finish(
         &mut self,
-        clock: &Clock,
+        clock: &dyn Clock,
         user_session: BrowserSession,
     ) -> Result<BrowserSession, Self::Error>;
     async fn list_active_paginated(
@@ -45,7 +45,7 @@ pub trait BrowserSessionRepository: Send + Sync {
     async fn authenticate_with_password(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user_session: BrowserSession,
         user_password: &Password,
     ) -> Result<BrowserSession, Self::Error>;
@@ -53,7 +53,7 @@ pub trait BrowserSessionRepository: Send + Sync {
     async fn authenticate_with_upstream(
         &mut self,
         rng: &mut (dyn RngCore + Send),
-        clock: &Clock,
+        clock: &dyn Clock,
         user_session: BrowserSession,
         upstream_oauth_link: &UpstreamOAuthLink,
     ) -> Result<BrowserSession, Self::Error>;
diff --git a/crates/tasks/src/database.rs b/crates/tasks/src/database.rs
index 66068860..9e31880c 100644
--- a/crates/tasks/src/database.rs
+++ b/crates/tasks/src/database.rs
@@ -14,7 +14,7 @@
 
 //! Database-related tasks
 
-use mas_storage::{oauth2::OAuth2AccessTokenRepository, Clock, Repository};
+use mas_storage::{oauth2::OAuth2AccessTokenRepository, Repository, SystemClock};
 use mas_storage_pg::PgRepository;
 use sqlx::{Pool, Postgres};
 use tracing::{debug, error, info};
@@ -22,7 +22,7 @@ use tracing::{debug, error, info};
 use super::Task;
 
 #[derive(Clone)]
-struct CleanupExpired(Pool<Postgres>, Clock);
+struct CleanupExpired(Pool<Postgres>, SystemClock);
 
 impl std::fmt::Debug for CleanupExpired {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -57,5 +57,5 @@ impl Task for CleanupExpired {
 #[must_use]
 pub fn cleanup_expired(pool: &Pool<Postgres>) -> impl Task + Clone {
     // XXX: the clock should come from somewhere else
-    CleanupExpired(pool.clone(), Clock::default())
+    CleanupExpired(pool.clone(), SystemClock::default())
 }